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Un nuevo genero para Habrothrix angustidens y Akodon serrensis (Rodentia, Cricetidae): de nuevo palentologia y neontologia se encuentran en el legado de Lund.

A NEW GENUS FOR Habrothrix angustidens AND Akodon serrensis (RODENTIA, CRICETIDAE): AGAIN PALEONTOLOGY MEETS NEONTOLOGY IN THE LEGACY OF LUND

INTRODUCTION

During the last 2 decades, several species of sigmodontine rodents named by Winge (1887) based on material from the rich paleontological deposits of Lagoa Santa area (Minas Gerais, Brazil) were recognized as senior synonyms of living entities (e.g., Voss, 1993; Voss and Carleton, 1993; Musser et al., 1998; Pardinas and Teta, 2011, 2013). These findings, partly based on earlier observations (e.g., Avila-Pires, 1960; Massoia and Fornes, 1965; Hershkovitz, 1966) helped identify redundancies in sigmodontine classification. In addition, these studies provided new data for understanding the tempo and mode of evolution of this rodent group and its past diversity (Voss, 1988; Voss and Myers, 1991). In fact, of 25 species recorded by Winge (1887) in Quaternary deposits (summarized in Voss and Myers, 1991:table 4), only Habrothrix angustidens, Habrothrix clivigenis, Oxymycterus cosmodus, Oxymycterus talpinus, and Calomys anoblepas, still remain as presumptively extinct forms (Pardinas and Teta, 2013).

During the course of our studies of the collections of Lund housed in the Danish city of Copenhagen, once again paleontology meets neontology. Habrothrix angustidens Winge, 1887, a putative fossil species recorded from the area of Lagoa Santa, Minas Gerais, Brazil, appears morphologically undistinguishable from Akodon serrensis Thomas, 1902, a living form from the Atlantic Forest of Argentina and Brazil. The present paper documents this synonymy--first found and generously communicated to us by Robert Voss--and proposes a new genus for both forms. The need for a new genus was uncovered by the phylogenetic analyses of D'Elia (2003) and D'Elia et al. (2003), who employed mitochondrial and nuclear DNA sequences and broad taxonomic coverage and recovered A. serrensis as sister to Thaptomys and not as part of the genus Akodon. That hypothesis is here morphologically and karyologically supported and expanded through descriptions and comparisons against related genera that conform the Akodon Division (sensu D'Elia, 2003) of the tribe Akodontini (see also D'Elia and Pardinas, 2015).

MATERIALS AND METHODS

In this report we studied fossil and recent specimens (see Appendix 1) housed at the following institutions: American Museum of Natural History, New York, USA (AMNH); The Natural History Museum, London, UK (BMNH); Centro Nacional Patagonico, Puerto Madryn, Argentina (CNP); Field Museum of Natural History, Chicago, USA (FMNH); Coleccion Nacional de Mastozoologia, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia," Buenos Aires, Argentina (MACN); Museu Nacional, Rio de Janeiro, Brazil (MN); Museu de Zoologia, Departamento de Biologia Animal, Universidade Federal de Vinosa, Vinosa, Minas Gerais, Brazil (MZUFV); Universitets Zoologisk Museum, Copenhagen, Denmark (ZMK); and voucher specimens CIT and BIO that will be deposited at Museu de Zoologia, Universidade de Sao Paulo, Sao Paulo, Brazil. Fossil specimens are represented by craniodental fragments; recent specimens are preserved as dry skins, skulls, skeletons and individuals stored in fluid. Most of the studied material came from several localities in southeastern Brazil, while a few are from Misiones Province in northeastern Argentina (see an annotated gazetteer of recording localities in Supplementary Material S1).

Anatomical descriptions and terminology follow Reig (1977), Carleton (1980), Voss (1988), and Carleton and Musser (1989). Standard external measurements (length of head and body; length of tail; length of hind foot with and without claw; length of ear from notch; all in millimeters) and weight (in grams) were transcribed from the specimen labels or museum catalogs as originally recorded by collectors. Craniodental dimensions were taken using a digital caliper and recorded to the nearest 0.01 mm and follow definitions provided by Weksler and Geise (1996) and Voss et al. (2002). They were, arranged in alphabetical order: breadth across M1s, breadth across occipital condyles, breadth of braincase, breadth of incisive foramina, breadth of M1, breadth of rostrum, breadth of zygomatic plate, condylo-incisive length, depth of incisor, height of skull, height of mandible, least interorbital breadth, length of bulla, length of diastema, length of incisive foramina, length of mandible, length of orbital fossa, length of palatal bridge, length of rostrum, length of maxillary molar row, and zygomatic breadth. Measured specimens were sorted into age categories following toothwear classes defined for Zygodontomys by Voss (1991). Because our aim is to provide a general characterization of a new genus, we adopt a univariate statistics approach based on mean values for large samples of adult individuals (toothwear classes 3-5).

Karyotypes from selected specimens (see Appendix 1) were prepared in the field. Chromosomes at metaphases were obtained via in vitro culture (culture of bone marrow grown in Dulbecco's MEM with 10% fetal bovine serum and colchicine [10.sup.-6] M), following incubation in KCl 0.075M solution at 37[grados]C by 40 minutes, centrifuged, fixed in Carnoy solution (methanol: acetic acid, 3:1), dropped onto clean slides and air-dried (Geise, 2014). Conventional coloration with Giemsa 5% was used to observe diploid (2n) and fundamental (FN, excluding sexual chromosomes) numbers and chromosome morphology variation; 50 metaphases of each specimen were analyzed with a Nikon Eclipse 50i photomicroscope under 1000 x magnification. Karyotypes were compared with literature reports. For intergeneric chromosomal comparisons, Deltamys sp. (CIT 944, male, Esmeralda, Rio Grande do Sul, Brazil), Necromys lasiurus (CIT 952, male, Rio Formoso, Pernambuco, Brazil), Thalpomys lasiotis (BIO 288, male, Brasilia, Distrito Federal, Brazil), and Thaptomys nigrita (CIT 331, male, Iguape, Sao Paulo, Brazil), metaphases were also obtained from fibroblast cell cultures derived from ear biopsies grown in Dulbecco's modified Eagle's medium supplemented with 20% fetal calf serum. For all species, GTG-banding was based on routine cytogenetic procedures, and FISH with whole chromosome probes was conducted following Ventura et al. (2009) using the Akodon paranaensis chromosome set as paints. FISH with telomeric probes was also performed only on T. lasiotis using Telomere PNA FISH Kit/FITC (K 5325-Dako) following the manufacturers' protocol for the purpose of cytogenetic comparisons. After FISH, the slides were counterstained with DAPI diluted in Vecta-shield (Vector) and analyzed using a fluorescence microscope (Zeiss Axiophot) equipped with software for image capture (MetaSystems).

RESULTS AND DISCUSSION

Taxonomic history

Habrothrix angustidens was described by Winge (1887:28-29) based on fossil remains recovered by the Danish naturalist Peter Lund in Lagoa Santa cave deposits in the first half of the XIX century. Winge (1887) also recognized or named 5 other forms in Habrothrix. One of these, H. clivigenis was referred to Akodon by Trouessart (1898) and remains a putative fossil form. The other 4, H. cursor, H. orycter, H. lasiotis, and H. lasiurus are now allocated, respectively, to the recent genera Akodon, Thaptomys, Thalpomys, and Necromys. Interestingly, all these genera belong to the tribe Akodontini. This highlights the accurate systematic perception of Winge, despite working mostly with fragmentary fossil material representing a large number of taxonomic groups.

Winge (1887:28) emphasized the similarities between H. angustidens with H. cursor but also was impressed by the absence of a capsular projection of the incisors and the smaller size of the former. He specifically highlighted the peculiar condition of the dentition of H. angustidens, and most remarkably, mentioned the difficulty of distinguishing the enamel from the dentine on the occlusal surfaces. Winge (1887:pl. II, figure 9) illustrated 2 remains belonging to H. angustidens, both from Lapa da Serra das Abelhas; an anterior skull fragment and a right mandible. Shortly after, Trouessart (1898:536) listed H. angustidens under Akodon; this action must be viewed as a taxonomic act without major implications because this author transferred to this genus all the Habrothrix species of Winge plus a wide array of sigmodontine forms.

In 1902 Oldfield Thomas received from Brazil a large mammal collection made by Alphonse Robert in the Serra do Mar of the Brazilian state of Parana. Thomas (1902:61) recognized one sigmodontine as new and described it as Akodon serrensis with type locality at "Roca Nova ... at an altitude of about 1000 meters" (Thomas, 1902:59). Thomas also received in the same collection specimens of A. cursor, and he directly compared both species. Akodon serrensis was characterized basically on coloration traits and said to be intermediate in size between A. azarae (= "arenicola" in the original work) and A. cursor. Thomas (1902:61) also noted "molars very large in proportion, as large as those of the much bigger species A. cursor; " however, he did not make any mention about their morphology.

Miranda Ribeiro (1905:188) added a new name to the nominal forms allied to A. serrensis. Based on a single female from Retiro de Ramos (also known as Retiro do Ramos), Rio de Janeiro, Brazil, he erected [Hesperomys] (A.) serrensis var. leucogula, a subspecies characterized by a more olive dorsal coloration, a yellowish-ochraceous belly, and a narrow pure white band in the lower part between the chin and the anterior limbs.

The XXth century passed without major systematic or nomenclatural modifications. While H. angustidens was basically forgotten, A. serrensis--including H. (A.) serrensis leucogula--was maintained under Akodon from the time of the catalog of Gyldenstolpe (1932) up to the more recent treatments (e.g., Musser and Carleton, 2005; Patton et al., 2015). Hershkovitz (1990a:14) ranked leucogula as a valid and different species from serrensis, including both forms in an informal group that he named Akodon mollis size class. Other researchers addressed morphological and chromosomal considerations of A. serrensis populations, especially in southern Brazil. In part, these studies were triggered by a misunderstanding involving several species of the A. cursor group (sensu Smith and Patton, 2007) and A. serrensis. This contorted history, which started when Liascovich and Reig (1989) erroneously referred one Argentinean Akodon specimen to A. serrensis and reported for it a diploid complement of 44, was fully resolved by Christoff et al. (2000; see also Pardinas et al., 2003; Gonsalves et al., 2007). It is of interest to transcribe a paragraph of Liascovich and Reig (1989:394) in order to reflect the understanding of A. serrensis at that time: "Akodon serrensis is similar to A. cursor in size and color pattern, and the two species are difficult to distinguish based on external characters. Fresh skins of A. serrensis have a conspicuously more ochraceous venter, especially evident in the anal region; however, even this distinction must be confirmed by examination of a large series of specimens. The skulls of both species also are similar in having long, narrow rostra, moderately inflated frontal regions, short zygomatic plates, a reduced interparietal, and elongated palatal foramina that reaches the level of the protocone of M1. The main differences between the two species are: the nasals are longer and project farther behind the maxillo-frontal suture in A. cursor; the zygomatic plate is much deeper in A. serrensis; the palate is shorter in A. cursor, its posterior border terminating anterior to the level of the alveoli of M3; the molars are narrow, elongated, and larger in A. serrensis; and the mandible in A. cursor is slender and elongated with a more posteriorly projecting condylar process and a more inflated capsular projection (root of incisor)." It is difficult to know how influential it was that one of the specimens used by Liascovich and Reig (1989) was, in reality, an Akodon paranaensis (see Pardinas et al., 2003; Gonsalves et al., 2007). Despite having the holotype of A. serrensis in hand, these authorities failed to distinguish these species. This necessitates that we call attention to the similarity of A. serrensis and other species of the cursor group of Akodon (e.g., cursor, montensis, paranaensis).

However, a new scenario emerged from molecular studies. D'Elia et al. (2003:358) explicitly called attention to the generic position of A. serrensis as follows: "A novel finding of our study with respect to akodontine systematics is the placement of Akodon serrensis well outside the Akodon clade ... A. serrensis appears as sister to the monotypic genus Thaptomys, and this clade is sister to the genus Necromys ... The phylogenetic position of Akodon serrensis is surprising because to the best of our knowledge nobody has cast doubt upon the inclusion of A. serrensis within the genus Akodon ... We will not make any taxonomic judgment about this topology until further studies ... are carried out. However, a combined analysis of nuclear and mitochondrial DNA sequences points in the same direction" In fact, D'Elia (2003:319) revisited this topic in a combined cytb and IRBP analysis "Ten extra steps are needed to force A. serrensis within the Akodon clade. Akodon serrensis appears to be sister to the monotypic genus Thaptomys (node 18), although this relationship is weakly supported (JK<50%, BS = 1). This clade is sister to the clade Thalpomys-Necromys. Further studies, including morphological comparisons and the sequencing of additional specimens, are needed to determine if A. serrensis should be placed on its own genus or in Thaptomys" Despite the relevance, these findings were basically ignored in the chromosomal research developed with Akodon species in southeastern Brazil (e.g., Ventura et al., 2006; Hass et al., 2008; Bonvicino, 2011). More recently, analyzing cytb over a taxonomically diverse sample of Akodon, Smith and Patton (2007:848) corroborated the separate position of serrensis although they highlighted its alternative relationship to Akodon + Deltamys rather than Thaptomys.

The taxonomic hypothesis that H. angustidens and A. serrensis were congeners was achieved by R. Voss after a restudy of the type material of both forms. According to him "The type series of Habrothrix angustidens consists of subfossil cranial fragments and disassociated hemimandibles from several caves in the vicinity of Lagoa Santa ... All of this material qualifies as syntypes because Winge did not designate a holotype ... Altogether, this material ... preserves the entire upper and lower dentition, the left zygomatic plate, diastema, palate, interorbital region, and mandibles. We compared this material side-by-side with a complete topotypical cranium of Akodon serrensis (ZMUC 1257) and found these two taxa to be phenotypically indistinguishable. In addition to qualitative resemblances, the few measurements that we were able to take from the lectotype of angustidens all fall within the range of variation seen in the topotypic series of serrensis. The only possible taxonomic conclusion is that angustidens and serrensis are synonyms" (R. Voss, in litt. November 4, 2008; Supplementary Material S2).

SYSTEMATICS

Family Cricetidae Fischer, 1817

Subfamily Sigmodontinae Wagner, 1843

Tribe Akodontini Vorontsov, 1959

Castoria, gen. nov.

Figs. 2-5; Tables 1-3

Synonymy.--

Habrothrix sensu Winge (1887:28), part, not Habrothrix Wagner, 1843

Akodon sensu Thomas (1902:61), part, not Akodon Meyen, 1833

Hesperomys sensu Miranda Ribeiro (1905:188), part, not Hesperomys Waterhouse, 1839

Type species.--Habrothrix angustidens Winge, 1887.

Etymology.--In homage to Castor Cartelle, a contemporany paleontologist (born in Ourense, Spain in 1938) studying Quaternary Brazilian mammalian fauna who effectively resurrected in Brazil the genius and figure of Peter W. Lund (see Cartelle, 2002). Continuous efforts of Cartelle over the last 4 decades have enlarged our knowledge of biotic evolution in tropical areas through the excavation, cleaning, sorting, and study of a huge quantity of osteological material recovered from karstic caves in northeastern Brazil.

Geographic distribution.--Known from southeastern Brazil and the northeastern tip of Argentina, roughly between 20[grados] to 30[grados]S and mostly restricted to an elevational range above 800 m (Fig. 1; Supplementary Material S1).

Chronological distribution.--Late Pleistocene? -Recent. Fossils were found in 5 cave deposits Lapa do Capao Secco, da Cerca Grande, a chamber near Escrivania, Quebra Chavelha, and Serra das Abelhas- in the area of Lagoa Santa, Minas Gerais, Brazil (Winge, 1887). Absolute radiometric dates performed on fossils and breccias excavated by Lund from Lagoa Santa indicate an array of ages covering at least the last 0.5 MA (e.g., Auler et al., 2006).

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Contents.--Tentatively, the genus is considered to be composed by one species, Castoria angustidens (Winge, 1887), nov. comb. Neither morphology nor metrics (Table 1) allow us to distinguish, at the specific level, the anterior skull portion that represents H. angustidens from those of living populations traditionally ascribed to A. serrensis. In fact, an exploratory multivariate analysis based on principal components placed the lectotype of H. angustidens within the morphospace of recent Brazilian specimens of A. serrensis (Supplementary Material S3). Minor differences between the fossil H. angustidens fragment--particularly the narrow condition of the molar toothrow--and recent A. serrensis individuals are here attributed to age variation. Given the broad geographic range of this genus and modest morphometric segregation (results not shown; see also Kosloski, 1997), the variation of Castoria is a topic that deserves further study. The names serrensis Thomas, 1902 and leucogula Miranda Ribeiro, 1905 are available.

[FIGURE 3 OMITTED]

Morphological diagnosis.--Rodents of the subfamily Sigmodontinae (sensu Reig, 1980) with the following combination of characters: small-medium size (head-and-body length ~ 95 mm; condylo-incisive length ~ 25 mm); tail shorter than head-and-body (~ 85% of head-and-body length); manual and pedal digits with short claws covered by long and sparse ungual tufts; pelage soft and long; skull robust with pointed rostrum, broad and somewhat flat interorbital region with frontal borders moderately divergent backwards, and enlarged braincase without patent crests; broad, anteriorly rounded, and slanting zygomatic plate; zygomatic arches with their lower border parallel with respect to the alveolar plane; long incisive foramina, anteriorly constricted, with expanded palatal process of premaxillary; short, broad, and flat bony palate; broad mesopterygoid fossa with anterior margin rounded; alisphenoid strut present; tegmen tympani overlapping squamosal with the participation of a distinct posterior suspensory process of the latter bone; carotid arterial circulation pattern primitive; bullae short and rounded; upper incisors opisthodont; molars noticeable large in relation to the cranium proportions, terraced, enlarged, and moderately hypsodont; main molar cusps arranged in opposite pairs; M1 without anteromedian flexus with large procingulum and marked trilophodont pattern; M3 with cylindrical outline; m1 with anteromedian flexid weakly present and procingulum anterior-posteriorly compressed; m1-2 with small ectolophids present and mesolophids probably fussed to metaconids; length of m2 slightly shorter than those of m1; length of m3 subequal than those of m2; lower incisor alveolus without distinct capsular process on lateral dentary surface; gall bladder present; stomach unilocular and hemiglandular; diploid number (2n) = 46 and fundamental number (FN) = 46.

Morphological description.--The following description is based on representative samples from localities in Minas Gerais and Rio de Janeiro states in Brazil and 2 individuals from Argentina. It aims to provide a general characterization of the genus. Additional morphological details and measurements can be found in Hershkovitz (1998:215-218).

[FIGURE 4 OMITTED]

Castoria includes small-medium sized sigmodontine rodents (Tables 1 and 2) characterized by a darker general coloration above and below, short mystacial vibrissae, short claws, and a moderately long tail although shorter than the combined length of head and body. The dorsal and ventral colors are subtly delimited with weak countershading (Supplementary Material S4). The skins exhibit thick, soft fur (guard hairs ~ 9 to 12 mm); the cuticle pattern of guard hairs was described as narrow and leaf-shaped; medullar pattern of these same hairs were a mixture of alveolar and striped types, with three to four layers of cells of irregular shape (Silveira et al., 2013). The dorsal fur is dark yellowish- to orangish-brown; the ventral surface is washed with bright buff or tawny over dark-gray hair bases. The eyes are small. The mystacial vibrissae are short, not extending posteriorly much beyond the base of the pinnae; genal vibrissae are present. The ears are medium in size, rounded, and internally and externally covered by brown hairs. The tail is dark brown, unicolored, and sparsely haired, covered by sets of 3 somewhat hispid hairs per scale, each dorsal hair covering 2-3 scale-rows; apical tuft absent. The manus and pes in Castoria are covered with short hairs, with their basal portion brown and apical portion whitish. The claws, basally open on the pes, are inconspicuous and dorsally covered by several whitish or darker ungual hairs slightly surpassing their apices. The plantar surface is naked, pigmented, and slightly squamated (sensu Pacheco, 2003). The pes has 6 pads, 4 interdigital and 2 plantar, the thenar and hypothenar; the thenar pad is enlarged and narrow; the hypothenar pad is subequal in size to the 1st interdigital pad; dIII and dIV are the largest, subequal in size and showing a slightly syndactylous condition (Fig. 2).

[FIGURE 5 OMITTED]

The skull in dorsal view is characterized by a flat, broad appearance with a pointed rostral region and a rounded braincase (Fig. 3). The nasals are pointed and usually slightly projecting beyond the anterior margin of the premaxillary (Fig. 4A). The rostrum is flanked by shallow but distinct zygomatic notches (Fig. 4B); the frontal sinuses are inflated and the interorbital region is broad, with rounded supraorbital margins in young and adult specimens (older animals develop small, sharp, convergent postorbital edges). The zygomatic arches are delicate, widest across the squamosal roots; they converge anteriorly and their midportions run parallel to the alveolar plane; the jugal is well developed (Fig. 4C). The braincase is large, smooth, and globose; the lambdoid crests are developed only in older individuals. The interparietal varies in size and form, being typically rhomboidal and compressed. The zygomatic plate in lateral view has a straight anterior margin that aligns vertically or slopes slightly backward; the origin of the superficial masseter is marked by a scar (not a tubercle) that is just below and slightly behind the anteroventral margin of the zygomatic plate. The foramina of the carotid circulation consist of pattern 1 (sensu Voss, 1988); a thick alisphenoid strut is present, and the subsquamosal fenestra is large (Figs. 4G and 4H). The incisive foramina are long (extending between the M1 anterocones) and characterized by a constricted anterior portion (at or near the premaxillary-maxillary sutures) and a markedly inflated premaxillary process (Fig. 4E); the palate is broad and uncomplicated by keels or deep lateral grooves; and the mesopterygoid fossa extends anteriorly to or between the M3s (Fig. 4F). There are no large posterolateral palatal pits, just tiny foramina flanking the mesopterygoid fossa. The mesopterygoid roof is perforated by very narrow but long sphenopalatine vacuities (Fig. 4F). The auditory bullae are small and flask-shaped, with broad bony Eustachian tubes.

The mandible is relatively robust, moderately low and elongated; the lower border of the ramus bends upward and backward behind the level of the m2 and descends again behind the m3. The mental foramen opens on the dorsolateral surface of the diastema. The alveolus of the lower incisor is contained in a ridge, not a distinct process, on the lateral surface of the mandible behind the base of the coronoid process. The angular process is pointed and bent upwards (Fig. 4I).

The upper incisors are opisthodont in orientation, with yellow-orange enamel bands, straight or very slightly inclined in frontal view and sharp, not inclined medially in ventral view (cf. Voss, 1988:376-377). The exterior edge of the upper incisors shows a thick enamel band; the dentine lake is straight (sensu Steppan, 1995:figure 10). The molars are very narrow in proportion to their length, with a marked unilateral tubercular hypsodonty (sensu Hershkovitz, 1962:89; Fig. 4D). They are also characterized by the opposite pattern of the main cusps, strongly bi-level (subadults) to terraced (adults) coronal surface (sensu Hershkovitz, 1962:86), simplification, and a tendency to retain little occlusal detail even in young animals; the cusps and lophs wear rapidly away, exposing large dentine basins (Fig. 5). The latter feature, shared with other akodontines (e.g., Akodon, Oxymycterus), makes it necessary to study a series of individuals of different ages in order to adequately assess dental variation. The upper molar tooth-rows are parallel or slightly convergent backwards in adult and old-adult specimens. The M1 is typically composed by 3 subequal "lobules" characterized by central basins and abrupt posterior walls inclined backwards. The procingulum lacks any trace of an anteromedian flexus and shows a well-developed surface occlusal area. The paracone "lobule" is the largest because it likely involves the mesoloph plus the paralophule; a trace of the latter is present as an acute posterior edge. The proto- and hypoflexus are subequals and scarcely developed, while para- and metaflexus are moderately directed backwards, with their internal margins reaching the middle line of the molar; the mures flanked by these flexus are particularly enlarged, lingually disposed, and longitudinally oriented. No evidence of a free posteroloph was detected in any studied specimen. The M2 shows a tetralophodont pattern with anteroloph and posteroloph obsolescent in young individuals to bilophodont in adults. The metacone "lobule" is smaller than the paracone one. The M3 is certainly complex in juveniles, with an internal enamel ring of equivocal identity (mesofossette?) and reduced hypoflexus and posterior lobe. In subadult to adult individuals, M3 acquires a cylindrical outline without internal accidents. We documented a deformation of the occlusal figure of the upper molars by the differential wear of labial and lingual sides as a consequence of age; whereas the labial portion is partially eroded to the coronal base, the lingual remains with persistent striae and thicker enamel. Lower molars are characterized by occlusal simplicity in subadult and adult individuals, a compressed procingulum mostly fused with the remainder portion of the m1, and a large m3 subequal to or even exceeding the m2 in length.

On the basis of 9 individuals, Castoria has 13 thoracic ribs, 13 thoracic vertebrae, 6 lumbar vertebrae, and 29-30 caudal vertebrae. The sacrum involves 3 subequal and squared sacral vertebrae. The neural spine of the axis is enlarged anteriorly-posteriorly and is fan-shaped. The neural spine of the 2nd thoracic vertebra is enlarged, twice or more as long as nearby spines. The caudal vertebrae lack hemal arches but hemal processes are present starting between the 3rd and 4th caudal vertebrae, becoming most pronounced between the 5th and 6th, and then decreasing in size. Gross stomach morphology in Castoria conforms with the unilocular-hemiglandular type (sensu Carleton, 1973:figure 2), a widespread condition in sigmodontine rodents. The bordering fold bisects the stomach on a line from the incisura angularis to a point opposite it on the greater curvature (Supplementary Material S5). Animals from Rio de Janeiro, Sao Paulo, and Misiones indicate that a gall bladder is present (cf. Geise et al., 2004; this paper).

Cytogenetics.--The specimens of Castoria angustidens cytogenetically analyzed (Appendix 1) presented the same karyotype, with 2n = 46 and FN = 46 (Supplementary Material S6); the autosomes comprising 21 acrocentric pairs and 1 small metacentric pair (the smallest of the complement). The X chromosome is a medium-sized acrocentric, and the Y one of the smallest of the complement, also acrocentric. This karyotype was previously recorded for specimens collected in states of Rio de Janeiro (Geise et al., 1998; Olifiers et al., 2007), Parana (Barros-Battesti et al., 1998; Hass et al., 2008), Santa Catarina (Testoni et al., 2012), Minas Gerais (Moreira et al., 2009), and Espirito Santo (Bonvicino et al., 2002). Cytogenetic information is lacking for Argentinean populations; the animal referred to A. serrensis by Liascovich and Reig (1989) and characterized as having 2n = 44 (FN = 44) was correctly reidentified as Akodon paranaensis by Christoff et al. (2000).

Phylogeny.--Phylogenetic analyses of combined molecular markers (e.g., D'Elia, 2003; D'Elia et al., 2003; Smith and Patton, 2007) showed that Castoria belongs to the Akodon Division of the tribe Akodontini, a well-supported clade composed by the recent genera Akodon, Deltamys, Necromys, Podoxymys, Thalpomys, and Thaptomys (D'Elia, 2003; Leite et al., 2015). Within the Akodon Division, its position varies depending upon the molecular markers used, taxonomic sampling, and the type of analysis conducted. In fact, in those studies with moderate taxonomic coverage (e.g., excluding Vilela et al., 2014), Castoria was recovered as sister to a clade including Akodon + Deltamys (Smith and Patton, 2007; Ventura et al., 2013; Abreu et al., 2014; Pardinas et al., 2014b), but elsewhere, it appears as sister to Thaptomys (e.g. D'Elia, 2003; D'Elia et al., 2003), or as sister to Deltamys (Fabre et al., 2012; Leite et al., 2015). Despite its uncertain position, no study has recovered Castoria within or as sister to the genus Akodon. This finding supports the hypothesis that this lineage deserves generic recognition.

Comparisons.--The fact that A. serrensis remained allocated as a species of Akodon for more than a century is a clear signal of the strong morphological similarity between these 2 genera. In addition, some character traits that were used as evidence of the distinctiveness of some genera of the Akodon Division, such as the morphology of the male accessory glands (see Reig, 1987), were--and remain--unknown for A. serrensis. Castoria is smaller than Akodon cursor or Akodon montensis and can be externally distinguished by its shorter manual claws and overall darker coloration. The relative size of molar toothrows, noticeably larger in Castoria than in Akodon (as Gyldenstolpe, 1932:104 highlighted), the general morphology of the interorbital region--flat and divergent posteriorly in Castoria and smooth and hourglass-shaped in Akodon, and the marked differences in the development of the premaxillary process as seen through the openings of the incisive foramina--more inflated and extended in Castoria than in Akodon, are the main cranial features separating these genera (Fig. 6). However, there are more trenchant differences between Castoria and Akodon in molar morphology. Castoria displays a conspicuous pattern of opposite main cusps in contrast to Akodon where these elements are moderately alternating; in addition, the former lacks the anteromedian flexus that typically characterizes the M1 procingulum in Akodon species (Table 3; Fig. 7). An additional important trait to distinguish Castoria from species of the cursor group of Akodon, which are sympatric with Castoria, is the morphology of the incisive foramina. In Castoria, the foramina are constricted anteriorly, anterior to the premaxillary-maxillary suture. In Akodon, the margins are not constricted, and the lateral margins of the foramina are convex and wider medially, resembling parentheses and showing no changes in curvature (Fig. 6; see also Supplementary Material S7). However, this degree of morphological differentiation is considered as interspecific variation within the genera Handleyomys (cf. Voss et al., 2002:22) and Drymoreomys (Percequillo et al., 2011:371).

Thaptomys appears as the sister taxon for Castoria in some molecule-based phylogenies (e.g., D'Elia, 2003). Both share weak pelage countershaping and inflation of the premaxillary process. However, morphological differences are strong. Castoria has a moderately long tail and rostrum, contrasting with the shorter condition of both in Thaptomys. Castoria has a well-developed upper free margin of the zygomatic plate whereas Thaptomys does not. Castoria lacks the defined capsular projection of the lower incisor root characterizing the mandible of Thaptomys. A gall bladder is present in Castoria and absent in Thaptomys. Molar morphology in Thaptomys is very similar to that in Akodon, so that Castoria differs from Thaptomys in all the respects noted earlier regarding Akodon.

[FIGURE 6 OMITTED]

Although Castoria differs in numerous aspects with respect to Deltamys, both share weak countershading, a moderately long tail, and the general "soricine" external aspect. Their skulls are easily distinguished by the pointed rostrum and broad interorbital region of Castoria versus the comparatively shortened rostrum and narrow interorbital region of Deltamys. In addition, Castoria has a broad zygomatic plate and an alisphenoid strut whereas Deltamys has a narrow plate without free upper margin and lacks the alisphenoid strut. In keeping with the molecular phylogenetic hypothesis of Smith and Patton (2007), which recovered Castoria close to Delta mys, these genera show many similarities in molar occlusal morphology (Fig. 7). In particular, both have the main cusps arranged in opposite pairs, the tendency to a trilophodont M1 in adults, and an anteriorly-posteriorly compressed procingulum that coupled with its coalescence to the metaconid produce on the m1 a nearly bilophodont pattern. The GTG-banding patterns of Castoria chromosomes allowed the identification and pairing of all homologues (Supplementary Material S6), and therefore, comparisons with the GTG-banded chromosomes of Akodon paranaensis (2n = 44 and FN = 44; reported in Ventura et al., 2009). Chromosome painting using A. paranaensis (APA) revealed that a tandem rearrangement, in which chromosome 7 of A. paranaensis is homologous to two chromosome pairs (16 and 21) of Castoria angustidens, explains their differences in 2n and FN. Meanwhile, analyzed species of Akodon share the sequences of APA 7 conserved as one chromosome (see Ventura et al., 2009). Comparisons of karyotypes among C. angustidens and other closely related akodontines (Deltamys, Necromys, Thalpomys and Thaptomys), showed that two groups besides Akodon can also be delimited with respect to APA 7. The first group unites Castoria and Thaptomys, both with homologous sequences of chromosome 7 of A. paranaensis reorganized into two acrocentric chromosomes (data not shown).

The second group comprises Deltamys sp., Necromys lasiurus and Thalpomys lasiotis, which present the 2 chromosome pairs homologous to APA 7 (as Castoria and Thaptomys), but also presents an exclusive association of chromosomes APA 7 and APA 8. Castoria presents a distinct pattern and nature of heterochromatin, distributed in large and positive pericentromeric blocks after telomeric FISH with (TTAGGG) n sequences as probes (Ventura et al., 2006, as Akodon serrensis). Thalpomys lasiotis also exhibits a pericentromeric region rich in (TTAGGG)n-like sequences (for CBG-banding patterns see Yonenaga-Yassuda et al., 1987, as Akodon reinhardti, and Andrade et al., 2004); this homoplasic feature in light of currently understood phylogenetic relationships, suggests that accumulation of the (TTAGGG) n-like repetitive sequences could lead to generic-level differentiation in the Akodontini.

[FIGURE 7 OMITTED]

Natural History.--Castoria has been recorded in at least 44 localities, almost all in the Atlantic Forest of Brazil (41) and Argentina (3), encompassing 7 ecoregions (Supplementary Material S1). Little is known about its natural history. The principal vegetation where Castoria is recorded is humid mountain forest, including those with Araucaria augustifolia (Supplementary Material S8). The elevational range for Castoria collection localities is from 300 to 2100 m (correlation between latitude and elevation was r = 0.5; Supplementary Material S9). Usually Castoria is interpreted as an element of montane fauna (Gonsalves et al., 2007; Abreu et al., 2014). Paglia et al. (2012) reported the diet of this rodent as insectivorous/omnivorous, although the basis for this assessment is unknown. Morphometric analysis of the appendicular skeleton suggests that this species uses terrestrial locomotion (Coutinho et al., 2013). Vieira and Monteiro-Filho (2003) captured this mouse exclusively on the ground. Miranda Ribeiro (1905) indicates that Castoria inhabits "galerias subterraneas," that according to Voss (1993:35) possibly correspond to "shallow tunnels under matted roots and moss" and piles of litter in thickets of Chusquea. The species was the most frequently trapped small mammal in the Parque Estadual do Desengano, a disturbed montane forest (~1000-1425 m elevation) in the northern portion of Rio de Janeiro (Modesto et al., 2008). Castoria angustidens was also the dominant species among recorded sigmodontines in an elevational transect of Parque Estadual da Serra do Brigadeiro from 1200 to 1800 m, particularly at middle to upper elevations (1450-1800 m; Moreira et al., 2009). In Parque Nacional de Itatiaia, it was trapped in montane forests and "campos de altitude" up to ~2100 m (Geise et al., 2004). Captive animals fed mainly on pulp of fruits and also on small to medium-sized seeds of a wide array of plant species from the Atlantic Forest (Vieira et al., 2003). A rich assemblage of parasites, including Acari, Anoplura, and Siphonaptera has been recorded from Brazilian individuals (Barros-Battesti et al., 1998; Linardi and Guimaraes, 2000; Moraes et al., 2003). Teixeira et al. (2014) recorded natural spillover infection between this species and the Jabora strain of hantavirus, whose primary host is Akodon montensis. According to these authors, spillover infection in secondary hosts, including C. angustidens and A. paranaensis, may play an important role in maintaining the hantavirus sylvatic cycle during periods of low prevalence in primary hosts.

Biogeography.--Castoria is distributed in southeastern Brazil, from Espirito Santo to Rio Grande do Sul, and in Misiones, northeastern Argentina. Its distributional range overlaps those of other akodontine rodents, such as Blarinomys breviceps, Brucepattersonius spp., and Thaptomys nigrita. Unlike those taxa and other Atlantic Forest sigmodontines, Castoria is much restricted to a narrow coastal fringe at relatively high elevations (500-1600 m) in well conserved forest remnants. Most of the recorded localities are located within Serra do Mar coastal forests and Araucaria Moist forests ecoregions (Olson et al., 2001; Pardinas et al., 2015). The Serra do Mar is recognized as one of the more remarkable centers of endemism in South America, with evidence from plants (especially of the families Myrtaceae, Lauraceae, Melastomataceae, and Orchidaceae), birds, butterflies, amphibians, and mammals (Da Silva, 2000a and references therein). Araucaria Moist forests spread from middle-level plateaus of ~500 m to the high slopes (1600 m) of the Serra da Mantiqueira. Among 352 plant species recorded in this region, 47 (13.3%) are endemic; this moist forest is also recognized as an important endemic bird area (Da Silva, 2000b). Castoria has been recorded from the Bahia Coastal and Interior Forests and at ecotones with the Alto Parana Atlantic forests. At a regional scale, at least other 2 genera, Delomys and Juliomys, have similar distributions, with populations mostly restricted to these same ecoregions (see Pavan and Leite, 2011; Gonqalves and Oliveira, 2014). The genera Delomys and Juliomys comprise both widely distributed species as well as more elevationally restricted taxa. This pattern highlights the importance of montane topographies in the evolution of sigmodontines of the Atlantic Forest (Gonqalves and Oliveira, 2014) and identifies this area as a major center of diversification of this subfamily (Smith and Patton, 1999).

Conservation.--C. angustidens was categorized as "Least Concern" by the IUCN. Several arguments were used to justify this placement, including its wide distribution, presumed large populations, its presence in a number of protected areas (e.g., Parque Estadual do Desengano, Parque Estadual da Serra do Brigadeiro, Parque Nacional de Itatiaia, Parque Nacional da Serra dos Orgaos, Parque Nacional da Bocaina), and because "it is unlikely to be declining at nearly the rate required to qualify for listing in a threatened category" (http://www. iucnredlist.org/details/full/756/0). However, it is likely that some populations of this species have been negatively affected by habitat destruction and forest fragmentation.

Remarks.--Our systematic hypothesis involves fossil (H. angustidens) and recent materials (A. serrensis). This kind of taxonomic work is obviously limited owing to the anatomical incompleteness and absence of genetic information for the fossils. However, as discussed several times revisiting the Lund collections (Voss, 1993; Voss and Carleton, 1993; Pardinas et al., 2008), fossils of Lagoa Santa often preserve enough information to make confident inferences regarding both genus and species (Supplementary Material S2 and S10).

Winge's description of H. angustidens was explicitly based on multiple specimens, none of which was designated as type (Winge, 1887:28-29). Therefore, all of those specimens must be considered syntypes in accordance with Article 72.1.1 of the Code (ICZN). We designate as lectotype of H. angustidens--according to Article 74.1--the cranial anterior fragment illustrated by Winge (1887:II, figure 2); this fossil was recently numbered in ZMK collections as 1/1845:13246 and is associated with Winge's handwritten label saying "Habrothrix angustidens Tegnet [figured] ?Lapa da Serra das Abelhas" (Supplementary Material S10). In addition, a photograph of this specimen was published in the catalog of Hansen (2012:58-59).

The lectotype of H. angustidens comes from "Lapa da Serra das Abelhas," and like other fossils of the same provenience (e.g., the types of H. orycter or H. clivigenis) is fragmentary and stained yellowish by superficial concretions. Several of the caves worked by Lund--including Serra das Abelhas--were destroyed by human activities over the last 170 years; however, a few, such as Cerca Grande located about 16 km NW Lagoa Santa city, where H. angustidens was also recorded, still remain. It is noteworthy that, despite extensive surveys of modern mammal fauna made by Lund around Lagoa Santa, Castoria was not detected (cf. Voss and Myers, 1991). In fact, the nearest record for the species is from Fazenda da Neblina in the Parque Estadual da Serra do Brigadeiro (Moreira et al., 2009), ca. 200 km SE of Lagoa Santa. The Lapa da Serra das Abelhas sigmodontine assemblage includes 8 taxa without recent records of occurrence near Lagoa Santa, including Castoria, Delomys, Euryoryzomys, Juliomys, Sooretamys, and Thaptomys (Winge, 1887; Pardinas and Teta, 2013). The taxonomic structure of this assemblage is characterized by elements presently restricted to Atlantic Forest in mixture with Cerrado species, a non-analogue fauna probably triggered by cooling episodes during the Late Pleistocene (Voss and Carleton, 1993; Cartelle, 1999; Pardinas and Teta, 2013).

The cursory indication by Hershkovitz (1990a:14) concerning the synonymy of A. serrensis and Akodon pervalens Thomas, 1925, a poorly known form with type locality at Carapari (Tarija, Bolivia), must be dismissed. A. pervalens--judging from examination of its holotype and paratype--looks like a true Akodon, phenotypically similar to species of the A. cursor species group as earlier suggested by Myers (1989). Although the holotype of A. pervalens is old (see Jayat et al., 2007:210) and some of its cranial and dental features (e.g., broad interorbital region, nasals tapering forward, absence of anteromedian flexus on M1) recall those of older A. serrensis, these are only general resemblances produced by aging (Supplementary Material S7).

FINAL CONSIDERATIONS

Castoria belongs to a clade of akodontine genera historically understood as a part of Akodon (cf. Reig, 1987), which has recently been reorganized into several genera (for a review, see D'Elia and Pardinas, 2015). Morphological differences among Akodon, Deltamys, Thalpomys, Thaptomys, Necromys, and Castoria, as well as more controversial forms such as Microxus, are typically subtle (Table 3). This seems to be a signature of the Akodon Division, one that prevented the recognition of these different genera for most of the XXth century.

Since the 1970s, several distinctive lineages formerly subsumed in Akodon--directly or under subgeneric combinations--have been progressively elevated to full generic rank. Paradigmatic cases were Abrothrix (now included in a different tribe) and Thaptomys, but also more recently Thalpomys and Deltamys. Reig (1987:358) anticipated these changes when he wrote "I tentatively recognize a central genus Akodon, subdivided into five subgenera ... I do not deny, however, that more detailed and comprehensive further studies could eventually elevate some of these taxa to generic level" These generic partitions within Akodon were possible because of the accumulation of morphological and karyological information and were then consolidated by DNA-based phylogenetic analyses (e.g., Hershkovitz, 1990b; Smith and Patton, 1993, 1999, 2007; Geise et al., 2001; D'Elia, 2003; D'Elia et al., 2003; Pardinas et al., 2005; Jayat et al., 2010). It is interesting to point out that at least two putative genus-rank groupings remain subsumed under Akodon despite clear morphological indications about their singularities; these are Microxus and Hypsimys (see Reig, 1987:359-360; Ventura et al., 2000:497; Voss, 2003:20-21). Perhaps their retention in Akodon is more the result of historical inertia than of unequivocal phylogenetic support (see Patton et al., 1989; Smith and Patton, 2007). An example of such progress is the recent finding that Akodon bogotensis and Akodon latebricola are neither Akodon nor Akodontini (Alvarado-Serrano and D'Elia, 2013). The naming of Neomicroxus demonstrates that the content of Akodon, as presently understood containing about 38 living species (Pardinas et al., 2015), requires detailed morphological and molecular scrutiny.

Castoria adds a new piece to Akodontini historical biogeography. In fact, the exclusion of the Abrotrichini (see Smith and Patton, 1999), the inclusion of Scapteromyini (see Smith and Patton, 1999; D'Elia et al., 2005), and the elevation to genera of several erstwhile subgenera or species (Deltamys, Gyldenstolpia; D'Elia et al., 2003; Pardinas et al., 2008) have reshaped our vision about this diverse tribe. Of the 15 genera currently recognized (see Patton et al., 2015), three are Atlantic Forest endemic, Blarinomys, Brucepattersonius, and Thaptomys. Castoria offers further evidence for a potential area of endemism in southeastern Brazil, a picture also supported by several genera of non-akodontine sigmodontine rodents (Smith and Patton, 1999; Pardinas et al., 2014a; Prado et al., 2014) and echimyid rodents (Upham and Patterson, 2015:Fig. 1).

Recibido 30 setiembre 2015. Aceptado 13 abril 2016. Editor asociado: B Patterson

ACKNOWLEDGMENTS

Robert Voss (AMNH) deserves credit for recognizing the congeneric status between H. angustidens and A. serrensis. He helped us not only by providing this information but also the original notes of his study and provided casts of H. angustidens that are now housed in CNP collections. Rob's selfless attitude is an example that better communication among researchers is possible. J. Oliveira (MN) kindly provided on long-term loan a large sample of specimens collected at key localities in Brazil. C. Galliari, J. Notarnicola, M. Lareschi, and R. Robles shared field efforts in order to obtain Argentinean material for study. A. Bezerra photographed for us the holotype of A. serrensis. M. Lareschi provided parasitological data. Valuable specimens were freely accessed thanks to the curators D. Flores (MACN), J. Patton (MVZ), and B. Patterson (FMNH); K. L. Hansen (ZMK) kindly answered our request about Lund's collections in Copenhagen. This paper was partially funded by Agencia Nacional de Promocion Cientifica y Tecnologica (PICT 2008-547 and 2014-1039 to UFJP) and Consejo Nacional de Investigaciones Cientificas y Tecnicas PIP 6179 (to UFJP), Centro Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Coordenado de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Fundado Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), World Wildlife Fund (WWF) and UERJ/ Prociencia (to LG), and Fundado de Amparo a Pesquisa do Estado de Sao Paulo, FAPESP (BP.PD 2009/54300-0 to KV). Specimens from Rio de Janeiro state were collected under collecting license of IBAMA and ICMBio (license # 598633). This contribution was originally triggered by a suggestion of G. D'Elia who, after a decade of shared efforts and contributions of phylogenetic tips, declined to be an author; this manuscript also received significant input from P. Teta, who participated in several aspects of museum study and also in the masterful production of the figures. We are deeply grateful to all these individuals and institutions. Finally, it is important to mention that the manuscript benefited from three reviews, reflecting the zeal of the editors to ensure its quality; and also, the associate editor was deeply committed to ensure the linguistic correctness employed in the text. This is GEMA's (Grupo de Estudios de Mamiferos Australes) contribution #10.

LITERATURE CITED

ABREU M, AU CHRISTOFF, VH VALIATI, and LR de OLIVEIRA. 2014. New distribution records of Serra do Mar Grass Mouse Akodon serrensis Thomas, 1902 (Mammalia: Rodentia: Sigmodontinae) in the southernmost Brazil. Check List 10:655-659.

ALVARADO-SERRANO D and G D'ELIA. 2013. A new genus for the Andean mice Akodon latebricola and A. bogotensis (Rodentia: Sigmodontinae). Journal of Mammalogy 94:995-1015.

ANDRADE AFB, CR BONVICINO, DC BRIANI, and S KASAHARA. 2004. Karyologic diversification and phylogenetic relationships of the genus Thalpomys (Rodentia, Sigmodontinae). Acta Theriologica 49:181-190.

AULER AS, LB PILO, PL SMART, X WANG, D HOFFMANN, DA RICHARDS, RL EDWARDS, WA NEVES, and H CHENG. 2006. U-series dating and taphonomy of Quaternary vertebrates from Brazilian caves. Palaeogeography, Palaeoclimatology, Palaeoecology 240:508-522.

AVILA-PIRES FD. 1960. Roedores coleccionados na regiao de Lagoa Santa, Minas Gerais, Brasil. Arquivos do Museu Nacional, Rio de Janeiro 50:25-45.

BARROS-BATTESTI DM, M ARZUA, PM LINARDI, JR BOTELHO, and IJ SBALQUEIRO. 1998. Interrelationship between ectoparasites and wild rodents from Tijucas do Sul, State of Parana, Brazil. Memorias do Instituto Oswaldo Cruz 93:719-725.

BONVICINO CR. 2011. Diversidade cariotipica em roedores Akodontini do Brasil. Boletim da Sociedade Brasileira de Mastozoologia, Rio de Janeiro 62:7-13.

BONVICINO CR, SM LINDBERGH, and LS MAROJA. 2002. Small non-flying mammals from conserved and altered areas of Atlantic Forest and Cerrado: Comments on their potential use for monitoring environment. Brazilian Journal of Biology 62:765-774.

CARLETON MD. 1973. A survey of gross stomach morphology in New World Cricetinae (Rodentia, Muroidea), with comments on functional interpretations. Miscellaneous Publications, Museum of Zoology, University of Michigan 146:1-43.

CARLETON MD. 1980. Phylogenetic relationships in neotomine-peromyscine rodents (Muroidea) and a reappraisal of the dichotomy within New World Cricetinae. Miscellaneous Publications, Museum of Zoology, University of Michigan 157:1-146.

CARLETON MD and GG MUSSER. 1989. Systematic studies of oryzomyine rodents (Muridae, Sigmodontinae): A synopsis of Microryzomys. Bulletin of the American Museum of Natural History 191:1-83.

CARTELLE C. 1999. Pleistocene mammals of the Cerrado and Caatinga of Brazil. Pp. 27-46, in: Mammals of the Neotropics. The Central Neotropics, Vol. 3 (JB Eisenberg and KH Redford, eds.). The University of Chicago Press, Chicago.

CARTELLE C. 2002. Peter W. Lund, a naturalist of several sciences. Lundiana 3:83-85.

CHRISTOFF AU, V FAGUNDES, IJ SBALQUEIRO, MS MATTEVI, and Y YONENAGA-YASSUDA. 2000. Description of a new species of Akodon (Rodentia: Sigmodontinae) from southern Brazil. Journal of Mammalogy 81:838-851.

COUTINHO LC, JA OLIVEIRA, and LM PESSOA. 2013. Morphological variation in the appendicular skeleton of Atlantic Forest sigmodontine rodents. Journal of Morphology 274:779-792.

DA SILVA JMC. 2000a. South America: Along the Atlantic coast of southeastern and southern Brazil. http:// www.worldwildlife.org/ecoregions/nt0160. Accessed on 2 June 2014.

DA SILVA JMC. 2000b. Araucaria moist forests. http:// www.worldwildlife.org/ecoregions/nt0101. Accessed on 2 June 2014.

D'ELIA G. 2003. Phylogenetics of Sigmodontinae (Rodentia, Muroidea, Cricetidae), with special reference to the Akodont group, and with additional comments on historical biogeography. Cladistics 19:307-323.

D'ELIA G and UFJ PARDINAS. 2015. Tribe Akodontini Vorontsov 1959. Pp. 140-144, in: Mammals of South America, Volume 2--Rodents (JL Patton, UFJ Pardinas, and G D'Elia, eds.). The University of Chicago Press, Chicago.

D'ELIA G, EM GONZALEZ, and UFJ PARDINAS. 2003. Phylogenetic analysis of Sigmodontinae rodents (Muroidea), with special reference to the akodont genus Deltamys. Mammalian Biology 68:351-364.

D'ELIA G, UFJ PARDINAS, and P MYERS. 2005. An introduction to the genus Bibimys (Rodentia: Sigmodontinae): Phylogenetic position and alpha taxonomy. Pp. 211-246, in: Mammalian diversification: from chromosomes to phylogeography. A celebration of the career of James Patton (EA Lacey and P Myers, eds.). University of California Press, Berkeley.

FABRE P-H, L HAUTIER, D DIMITROV, and E DOUZERY. 2012. A glimpse on the pattern of rodent diversification: A phylogenetic approach. BMC Evolutionary Biology 12:88.

GEISE L. 2014. Procedimentos geneticos iniciais na captura e preparado de mamiferos. Pp. 221-235, in: Tecnicas de estudos aplicadas aos mamiferos silvestres brasileiros (MR dos Reis, AL Peracchi, BK Rossaneis, and MN Fregonezi, org.). 2nd Edition, Technical Books Editora, Rio de Janeiro.

GEISE L, FC CANAVEZ and HNA SEUANEZ. 1998. Comparative karyology in Akodon (Rodentia, Sigmodontinae) from Southeastern Brazil. Journal of Heredity 89:158-163.

GEISE L, LG PEREIRA, DEP BOSSI, and HG BERGALLO. 2004. Pattern of elevational distribution and richness of non volant mammals in Itatiaia National Park and its surroundings, in southeastern Brazil. Brazilian Journal of Biology 64:599-612.

GEISE L, MF SMITH and JL PATTON. 2001. Diversification in the genus Akodon (Rodentia, Sigmodontinae) in southeastern South America: mtDNA sequence analysis. Journal of Mammalogy 82:92-101.

GEISE L, M WEKSLER, and CR BONVICINO. 2004. Presence or absence of gall bladder in some Akodontini rodents (Muridae, Sigmodontinae). Mammalian Biology 69:210-214.

GONQALVES PR and JA OLIVEIRA. 2014. An integrative appraisal of the diversification in the Atlantic forest genus Delomys (Rodentia: Cricetidae: Sigmodontinae) with the description of a new species. Zootaxa 3760:1-38.

GONQALVES PR, P MYERS, JF VILELA and JA OLIVEIRA. 2007. Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the campos de altitude. Miscellaneous Publications, Museum of Zoology, University of Michigan 197:1-24.

GYLDENSTOLPE N. 1932. A manual of Neotropical sigmodont rodents. Kunglia Svenska Vetenskapsakademiens Handlingar, Serie 3, 11:1-164.

HANSEN KL. 2012. E Museo Lundii--Addendum--A series of annotated catalogues based on subfossil and recent material. First Edition. Edited by the author, Copenhagen.

HASS I, IJ SBALQUEIRO, and S MULLER. 2008. Chromosomal phylogeny of four Akodontini species (Rodentia, Cricetidae) from Southern Brazil established by Zoo-FISH using Mus musculus (Muridae) painting probes. Chromosome Research 16:75-88.

HERSHKOVITZ P. 1962. Evolution of Neotropical cricetine rodents (Muridae) with special reference to the phyllotine group. Fieldiana, Zoology 46:1-524.

HERSHKOVITZ P. 1966. South American swamp and fossorial rats of the scapteromyine group (Cricetinae, Muridae) with comments on the glans penis in murid taxonomy. Zeitschrift fur Saugetierkunde 31:81-149.

HERSHKOVITZ P. 1990a. Mice of the Akodon boliviensis size class (Sigmodontinae, Cricetidae), with the description of two new species from Brazil. Fieldiana, Zoology, New Series 57:iii + 1-35.

HERSHKOVITZ P 1990b. The Brazilian rodent genus Thalpomys (Sigmodontinae, Cricetidae) with a description of a new species. Journal of Natural History 24:763-783.

HERSHKOVITZ P. 1998. Report on some sigmodontine rodents collected in southeastern Brazil with descriptions of a new genus and six new species. Bonner Zoologische Beitrage 47:193-256.

ICZN. 1999. International Code of Zoological Nomenclature, Fourth edition. International Trust for Zoological Nomenclature, London.

JAYAT P PE ORTIZ, UFJ PARDINAS, and G D'ELIA. 2007. Redescripcion y posicion filogenetica del raton selvatico Akodon sylvanus (Rodentia: Cricetidae: Sigmodontinae). Mastozoologia Neotropical 14:201-225.

JAYAT P, PE ORTIZ, J SALAZAR-BRAVO, UFJ PARDINAS, and G D'ELIA. 2010. The Akodon boliviensis species group (Rodentia: Cricetidae: Sigmodontinae) in Argentina: Species limits and distribution, with the description of a new entity. Zootaxa 2409:1-61.

KOSLOSKI MA. 1997. Morfometria craniana de uma populacao de Akodon serrensis Thomas, 1902 (Rodentia, Cricetidae) do municipio de Araucaria, Parana, Brasil. Revista Estudos de Biologia 41:61-87.

LEITE YLR, PJR KOK, and M WEKSLER. 2015. Evolutionary affinities of the 'Lost World' mouse suggest a late Pliocene connection between the Guiana and Brazilian shields. Journal of Biogeography 42:706-715.

LIASCOVICH RC and OA REIG. 1989. Low chromosomal number in Akodon cursor montensis Thomas and karyologic confirmation of A. serrensis Thomas in Misiones, Argentina. Journal of Mammalogy 70:391-395.

LINARDI PM and LR GUIMARAES. 2000. Sifonapteros do Brasil. Ed. Museu de Zoologia da Universidade de Sao Paulo, FAPESP, Sao Paulo

MASSOIA E and A FORNES. 1965. Notas sobre el genero Scapteromys (Rodentia Cricetidae). II. Fundamentos de la identidad especifica de S. principalis (Lund) y S. gnambiquarae (M. Ribeiro). Neotropica 11:1-7.

MIRANDA-RIBEIRO A. 1905. Vertebrados do Itatiaya (Peixes, Serpentes, Saurios, Aves e Mammiferos). Arquivos de Museu Nacional, Rio de Janeiro 13:163-190 + 3 plates.

MODESTO TC, FS PESSOA, MC ENRICI, N ATTIAS, T JORDAO-NOGUEIRA, LM COSTA, HG ALBUQUERQUE, and HG BERGALLO. 2008. Mamiferos do Parque Estadual do Desengano, Rio de Janeiro, Brasil. Biota Neotropica 8:153-159.

MORAES LB, DAP BOSSI, and AX LINHARES. 2003. Siphonaptera parasites of wild rodents and marsupials trapped in three mountain ranges of the Atlantic Forest in southeastern Brazil. Memorias do Instituto Oswaldo Cruz 98:1071-1076.

MOREIRA JC, EG MANDUCA, PR GONQALVES, MM MORAIS, RF PEREIRA, G LESSA, and JA DERGAM. 2009. Small mammals from Serra do Brigadeiro state park, Minas Gerais, Southeastern Brazil: Species composition and elevational distribution. Arquivos do Museu Nacional, Rio de Janeiro 67:103-118.

MUSSER GG and MD CARLETON. 2005. Superfamily Muroidea. Pp. 894-1531, in: Mammal species of the World: A taxonomic and geographic reference (DE Wilson and DM Reeder, eds.). 3rd edition, Johns Hopkins University Press, Baltimore.

MUSSER GG, MD CARLETON, EM BROTHERS and AL GARDNER. 1998. Systematic studies of oryzomyine rodents (Muridae, Sigmodontinae): Diagnoses and distributions of species formerly assigned to Oryzomys "capito" Bulletin of the American Museum of Natural History 236:1-376.

MYERS P. 1989. A preliminary revision of the varius group of Akodon (A. dayi, dolores, molinae, neocenus, simulator, toba and varius). Pp. 5-54, in: Advances in Neotropical Mammalogy (KH Redford and JF Eisenberg, eds.). Sandhill Crane Press, Inc., Gainesville.

OLIFIERS N, A CUNHA, C GRELLE, CR BONVICINO, L GEISE, L PEREIRA, M VIEIRA, P DANDREA, and R CERQUEIRA. 2007. Lista de especies de pequenos mamiferos nao-voadores do Parque Nacional da Serra dos Orgaos. Pp. 183-192, in: Ciencia e Conservado na Serra dos Orgaos (C Cronemberger and EB Viveiros de Castor, org.). Ibama, Brasilia.

OLSON DM, et al. 2001. Terrestrial ecoregions of the world: A new map of life on Earth. Bioscience 51:933-938.

PACHECO V. 2003. Phylogenetic analyses of the Thomasomyini (Muroidea: Sigmodontinae) based on morphological data. Unpublished Ph. D. dissertation, City University of New York, New York.

PAGLIA AP, et al. 2012. Lista anotada dos mamiferos do Brasil / Annotated checklist of Brazilian mammals. 2a Edicao / 2nd Edition. Occasional Papers in Conservation Biology 6:1-76.

PARDINAS UFJ and P TETA. 2011. On the taxonomic status of the Brazilian mouse Calomys anoblepas Winge, 1887 (Mammalia, Rodentia, Cricetidae). Zootaxa 2788:38-44.

PARDINAS UFJ and P TETA. 2013. Taxonomic status of Mus talpinus Lund (Rodentia: Sigmodontinae) from the Quaternary deposits of Lagoa Santa, Minas Gerais, Brazil and its paleoenvironmental meaning. Mammalia 77:347-355.

PARDINAS UFJ, G D'ELIA, and S CIRIGNOLI. 2003. The genus Akodon (Muroidea: Sigmodontinae) in Misiones, Argentina. Mammalian Biology 68:129-143.

PARDINAS UFJ, G D'ELIA, S CIRIGNOLI and P SUAREZ. 2005. A new species of Akodon (Rodentia, Cricetidae) from the northern campos grasslands of Argentina. Journal of Mammalogy 86:462-474.

PARDINAS UFJ, G D'ELIA, and P TETA. 2008 [2009]. Una introduccion a los mayores sigmodontinos vivientes: revision de Kunsia Hershkovitz, 1966 y descripcion de un nuevo genero (Rodentia: Cricetidae). Arquivos do Museu Nacional, Rio de Janeiro 66:509-594.

PARDINAS UFJ, G D'ELIA, G LESSA, M PASSAMANI, and P TETA. 2014a. Nuevos datos morfologicos y una hipotesis filogenetica para Phaenomys (Rodentia, Cricetidae). Mastozoologia Neotropical 21:251-261.

PARDINAS UFJ, G LESSA, P TETA, J SALAZAR-BRAVO, and EM CAMARA. 2014b. A new genus of sigmodontine rodent from eastern Brazil and the origin of the tribe Phyllotini. Journal of Mammalogy 95:201-215.

PARDINAS UFJ, P TETA, D ALVARADO-SERRANO, L GEISE, JP JAYAT, PE ORTIZ, PR GONQALVES, and G D'ELIA. 2015. Genus Akodon Meyen, 1833. Pp. 144-204, in: Mammals of South America, Volume 2--Rodents (JL Patton, UFJ Pardinas, and G D'Elia, eds.). The University of Chicago Press, Chicago.

PATTON JL, P MYERS, and MF SMITH. 1989. Electromorphic variation in selected South American akodontine rodents (Muridae: Sigmodontinae), with comments on systematic implications. Zeitschrift fur Saugetierkunde 54:347-359.

PATTON JL, UFJ PARDINAS, and G D'ELIA. 2015. Mammals of South America, Volume 2--Rodents. University of Chicago Press, Chicago.

PAVAN SE and YRL LEITE. 2011. Morphological diagnosis and geographic distribution of Atlantic Forest red-rumped mice of the genus Juliomys (Rodentia: Sigmodontinae). ZOOLOGIA (Curitiba) 28:663-672.

PERCEQUILLO AR, M WEKSLER, and LP COSTA. 2011. A new genus and species of rodent from the Brazilian Atlantic Forest (Rodentia: Cricetidae: Sigmodontinae: Oryzomyini), with comments on oryzomyine biogeography. Zoological Journal of the Linnean Society 161:357-390.

PRADO JR, PGG BRENNAND, LP GODOY, G LIBARDI, EF ABREU-JUNIOR, P ROTH, E CHIQUITO, and AR PERCEQUILLO. 2014. Species richness and areas of endemism of oryzomyine rodents (Cricetidae, Sigmodontinae) in South America: an ndm/vndm approach. Journal of Biogeography 42:540-551.

REIG OA. 1977. A proposed unified nomenclature for the enamelled components of the molar teeth of the Cricetidae (Rodentia). Journal of Zoology 181:227-241.

REIG OA. 1980. A new fossil genus of South American cricetid rodents allied to Wiedomys, with an assessment of the Sigmodontinae. Journal of Zoology 192:257-281.

REIG OA. 1987. An assessment of the systematics and evolution of the Akodontini, with the description of new fossil species of Akodon (Cricetidae: Sigmodontinae). Pp. 347-399, in: Studies in Neotropical mammalogy. Essays in honor of Philips Hershkovitz (BD Patterson and RM Timm, eds.). Fieldiana, Zoology, new series, 39.

SILVEIRA F, IJ SBALQUEIRO, and ELA MONTEIRO-FILHO. 2013. Identificado das especies brasileiras de Akodon (Rodentia: Cricetidae: Sigmodontinae) atraves da microestrutura dos pelos. Biota Neotropical 13:339-345.

SMITH MF and JL PATTON. 1993. The diversification of South American murid rodents: Evidence from mitochondrial DNA sequence data for the akodontine tribe. Biological Journal of the Linnean Society 50:149-177.

SMITH MF and JL PATTON. 1999. Phylogenetic relationships and the radiation of sigmodontine rodents in South America: Evidence from cytochrome b. Journal of Mammalian Evolution 6:89-128.

SMITH MF and JL PATTON. 2007. Molecular phylogenetics and diversification of South American grass mice, genus Akodon. Pp. 827-858, in: Studies in contemporary mammalian biology. Papers honoring the remarkable career of Oliver P Pearson, 1915-2003 (D Kelt, E Lessa, and J Salazar-Bravo, eds.). University of California Publications in Zoology, Berkeley.

STEPPAN SJ. 1995. Revision of the tribe Phyllotini (Rodentia: Sigmodontinae), with a phylogenetic hypothesis for the Sigmodontinae. Fieldiana, Zoology, new series 80:1-112.

TEIXEIRA BR et al. 2014. Population ecology of hantavirus rodent hosts in southern Brazil. American Journal of Tropical Medicine and Hygiene 91:249-257.

TESTONI AF, J FUMIS, SL ALTHOFF, FR TORTATO, and JJ CHEREM. 2012. Akodon serrensis Thomas, 1902 (Mammalia: Rodentia: Sigmodontinae): Records in Santa Catarina state, southern Brazil. Check List 8:1344-1346.

THOMAS O. 1902. On mammals from the Serra do Mar, Parana, collected by Mr. Alphonse Robert. Annals and Magazine of Natural History, series 7, 9:59-64.

TROUESSART EL. 1898. Catalogus mammalium tam viventium quam fossilium. Tomus 2. R. Friedlander and Sohn, Berlin.

UPHAM NS and BD PATTERSON. 2015. Evolution of caviomorph rodents: A complete phylogeny and timetree for living genera. Pp. 63-120, in: Biology of caviomorph rodents: Diversity and evolution (AI Vasallo and D Antenucci, eds.). SAREM Series A, Mammalogical Research, Volume 1, Buenos Aires.

VENTURA J, MJ LOPEZ-FUSTER, M SALAZAR, and R PEREZ-HERNANDEZ. 2000. Morphometric analysis of some Venezuelan akodontine rodents. Netherlands Journal of Zoology 50:487-501.

VENTURA K, PC O'BRIEN, Y YONENAGA-YASSUDA, and MA FERGUSON-SMITH. 2009. Chromosome homologies of the highly rearranged karyotypes of four Akodon species (Rodentia, Cricetidae) resolved by reciprocal chromosome painting: The evolution of the lowest diploid number in rodents. Chromosome Research 17:1063-1078.

VENTURA K, MJJ SILVA, V FAGUNDES, and AU CHRISTOFF. 2006. Non-telomeric sites as evidence of chromosomal rearrangement and repetitive (TTAGGG) arrays in heterochromatic and euchromatic regions in four species of Akodon (Rodentia, Muridae). Cytogenetic and Genome Research 115:169-175.

VENTURA K, MJJ SILVA, L GEISE, YRL LEITE, UFJ PARDINAS, Y YONENAGA-YASSUDA, and G D'ELIA. 2013. The phylogenetic position of the enigmatic Atlantic Forest endemic spiny-mouse Abrawayaomys (Rodentia: Sigmodontinae). Zoological Studies 52:55 doi:10.1186/1810-522X-52-55.

VIEIRA EM and ELA MONTEIRO-FILHO. 2003. Vertical stratification of small mammals in the Atlantic rain forest of south-eastern Brazil. Journal of Tropical Ecology 19:501-507.

VIEIRA EM, M PIZO, and P IZAR. 2003. Fruit and seed exploitation by small rodents of the Brazilian Atlantic forest. Mammalia 67:533-539.

VILELA JF, B MELLO, CM VOLOCH, and CG SCHRAGO. 2014. Sigmodontine rodents diversified in South America prior to the complete rise of the Panamanian Isthmus. Journal of Zoological Systematics and Evolutionary Research 52:249-256.

VOSS RS. 1988. Systematics and ecology of ichthyomyine rodents (Muroidea): patterns of morphological evolution in small adaptive radiation. Bulletin of the American Museum of Natural History 188:262-493.

VOSS RS. 1991. An introduction to the Neotropical muroid rodent genus Zygodontomys. Bulletin of the American Museum of Natural History 210:1-113.

VOSS RS. 1993. A revision of the Brazilian muroid rodent genus Delomys with remarks on "thomasomyine" characters. American Museum Novitates 3073:1-44.

VOSS RS. 2003. A new species of Thomasomys (Rodentia: Muridae) from Eastern Ecuador, with remarks on mammalian diversity and biogeography in the Cordillera Oriental. American Museum Novitates 3421:1-47.

VOSS RS and MD CARLETON. 1993. A new genus for Hesperomys molitor Winge and Holochilus magnus Hershkovitz, with comments on phylogenetic relationships and oryzomyine monophyly. American Museum Novitates 3085:1-39.

VOSS RS and P MYERS. 1991. Pseudoryzomys simplex (Rodentia: Muridae) and the significance of Lund's collections from the caves of Lagoa Santa, Brazil. Bulletin of the American Museum of Natural History 206:414-432.

VOSS RS, M GOMEZ-LAVERDE, and V PACHECO. 2002. A new genus for Aepeomys fuscatus Allen, 1912, and Oryzomys intectus Thomas, 1921: Enigmatic murid rodents from Andean cloud forests. American Museum Novitates 3373:1-42.

WEKSLER M and L GEISE. 1996. Medidas cranianas de roedores Sigmodontinae. Boletim da Sociedade Brasileira de Mastozoologia, Rio de Janeiro 30:1-2. WINGE H. 1887. Jordfundne og nulevende Gnavere (Rodentia) fra Lagoa Santa, Minas Geraes, Brasilien. E Museo Lundii 1(3):1-178 + 18 plates.

APPENDIX 1

Studied specimens belong to the following mammal collections: AMNH, American Museum of Natural History, New York, USA; BMNH, Natural History Museum, London, UK; CNP, Coleccion de Mamiferos del Centro Nacional Patagonico, Chubut, Argentina; FMNH, Field Museum of Natural History, Chicago, USA; MACN, Coleccion Nacional de Mastozoologia, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia," Buenos Aires, Argentina; MN, Museu Nacional, Rio de Janeiro, Brazil; MZUFV, Museu de Zoologia, Departamento de Biologia Animal, Universidade Federal de Vinosa, Vinosa, Minas Gerais, Brazil; ZMK, Universitets Zoologisk Museum, Copenhagen, Denmark. Symbols denote specific studies carried out on each specimen (* = measured; k = karyotyped).

Akodon montensis (n = 46): Argentina, Misiones, Balneario Municipal de Aristobulo del Valle sobre el arroyo Cuna Piru, 10 km NN W Aristobulo del Valle (CNP 1785, 1786, 1789, 1790, 1794, 1795, 1796, 1797, 1798, 1799, 1800, 1802, 1804, 1805, 1807, 1808, 1809, 1810, 1811, 1812, 1813, 1814, 1815, 1818, 1819, 1821, 1825, 1829, 1831, 1833, 1835, 1838, 1844, 1845, 1847), Reserva Privada de Usos Multiples Guarani (CNP 4243, 4244, 4245, 4247, 4248, 4249, 4250, 4251, 4252, 4253, 4254). Castoria angustidens nov. comb. (n = 123): Argentina, Misiones, Reserva Privada de Vida Silvestre Urugua-i (MACN 22246), RP 2, 6 km NE Arroyo Paraiso (CNP 449 *). Brazil, Minas Gerais, Parque Estadual da Serra do Brigadeiro, Fazenda da Neblina (MZUFV 520 *, 551 *, 1076, 1148 *, 1150 *, 1151 *, 1153 *, 1154 *, 1155 *, 1156 *, 1215 *, 1220 *, 1234, 1242, 1266 *, 1281 *, 1298 *, 1630, 1635, 1653, 1655, 2555; UFMG 1858 *, 1859 *, 1860 *, 1861 *, 1862 *), Parque Estadual da Serra do Brigadeiro, Serra das Caberas (MZUFV 1243 *, 1248 *, 1250 *, 1267 *, 1280 *, 1286 *, 1287 *, 1294 *, 1295 *), Lapa da Serra das Abelhas (ZMK 1/1845:13246 * [lectotype of H. angustidens]; CNP 4267 [lectotype: cast of upper molar row], CNP 4268 [paralectotype: cast of lower molar row]); Parana, Roca Nova (BMNH 3.7.1.66 *-3.7.1.73 *, ZMK 1257 *); Rio de Janeiro, Parque Nacional da Serra dos Orgaos, Vale das Antas (MN 69807 * (k), 69808 *, 69809 *, 69810 *, 69811 *, 69812 * k, 69813 *, 77085 *, 77099 * (k), 77100 *, 77101 *, 77102 *, 77104 *, 77105 *, 77108 *, 77111 *, 77112 *, 77113 *, 77116 *, 77117 * (k), 77119 *, 77121 *, 77122 *, 77123 *, 77078 * (k), 77079 * (k), 77081 *, 77082 *, 77084 * (k), 81130 *, 81131 *, 81133 *, 81134 *, 81135 *, 81136 *, 81137 *, 81138 *, 77086 *, 77087 * (k), 77088 *, 77090 *, 77091 *, 81144 *, 77096 *, 81147 *, 81148 *, 81150 *, 81151 *, 81152 *, 81153 *, 81154 *, 81155 *, 81156 *, 81157 *, 81158 *, 81159 *, 81160 *, 81161, 81162 *, 81163 *, 81164 *, 81165 *, 81166 *, 81168 *, 81169 *, 81170 *, 81171 *, 81172 *, 77097 * (k), 81175 *), Sitio Xitaca, Debossan, Nova Friburgo (MN 35912 *, 35920 *, 35921 *, 35923 *, 35924 *, 35926 *), Parque Nacional do Itatiaia (MN 69803 *), Retiro de Ramos (MN 2513 * [holotype of H. serrensis leucogula]), Visconde de Maua (MN 69804 *); Sao Paulo, Fazenda Intervales (FMNH 143275).

Deltamys kempi (n = 6): Argentina, Buenos Aires, La Balandra (CNP 581, 893, 3086, 3087, 4141), General Lavalle (CNP 2377).

Necromys lactens (n = 5): Argentina, Jujuy, Barcena, ca. 3 km S sobre RN 9 (CNP 1486), Abra de la Cienaga Negra (CNP 1487), San Francisco (CNP 3032, 3037, 4124).

Necromys lasiurus (n = 8): Argentina, Santiago del Estero, Estacion Experimental INTA "La Maria" (CNP 2358); Chaco, 5 km NW Puerto Las Palmas (CNP 3036, 3049); Misiones, Estancia Santa Ines (CNP 3038, 3041, 3043, 3045, 3048).

Necromys obscurus (n = 5): Argentina, Buenos Aires, Arroyo de las Brusquitas (CNP 891, 2380, 3039, 3047), Estacion Experimental INTA "Balcarce" (CNP 3053).

Thaptomys nigrita (n = 23): Argentina, Misiones, Balneario Municipal de Aristobulo del Valle sobre el arroyo Cuna Piru, 10 km NN W Aristobulo del Valle (CNP 1788, 1791, 1816, 1826, 1827, 1828, 1832, 1839, 1846, 1929, 1931), Refugio Mocona (CNP 1938, 3008, 3010, 3011), Asentamiento Aborigen Kaaguy Poty, 1 km NNW interseccion RP 7 y arroyo Cuna Piru (CNP 1979, 2370, 2371, 2372), Posada Las Malvinas (CNP 3526), Reserva Privada de Vida Silvestre Urugua-i (CNP 3875). Brazil: Minas Gerais, Parque Estadual da Serra do Brigadeiro, Fazenda da Neblina (MZUFV 1110, 1112)

SUPPLEMENTARY MATERIAL ONLINE

S1. Gazetteer of the recording localities for the genus Castoria. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup1.doc

S2. Study notes on Habrothrix angustidens and Akodon serrensis made by R. S. Voss in November, 2008. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup2.doc

S3. Principal component analysis of all age classes of Brazilian specimens of Castoria, including the lectotype of Habrothrix angustidens. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup3.doc

S4. External appereance of Castoria angustidens, nov. comb. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup4.doc

S5. Gastric morphology of Castoria angustidens, nov. comb. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup5.doc

S6. Chromosomes of Castoria angustidens, nov. comb. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup6.doc

S7. Comparison of the holotypes of Akodon pervalens and A. serrensis. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup7.doc

S8. Habitat of Castoria angustidens, nov. comb. at Itamonte, Brazil. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup8.doc

S9. Joint distribution of latitude and elevation for Castoria angustidens, nov. comb. collection localities. https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup9.doc

S10. Lectotype of Castoria angustidens, nov. comb. (ZMK 1/1845:13246). https://www.sarem.org.ar/wp-content/uploads/2016/06/SAREM_MastNeotrop_23-1_Pardinas-sup10.doc

S1.-Gazetteer of locality records for the genus Castoria.

This gazetteer summarizes geographical and ecological information about Castoria collection localities -arranged by increasing latitude- and habitats. Except where indicated, voucher specimens have been identified by direct examination and/or karyotype.

Acronyms

CJ--Field catalogue of Erika Hingst-Zaher.

CNP--Coleccion de Mamiferos, Centro Nacional Patagonico, Puerto Madryn, Chubut, Argentina.

MACN--Coleccion Nacional de Mastozoologia, Museo Argentino de Ciencias Naturales "B. Rivadavia," Buenos Aires, Argentina.

MN--Museu Nacional, Rio de Janeiro, Brazil.

MZUFV--Museu de Zoologia, Departamento de Biologia Animal, Universidade Federal de Vicosa, Vicosa, Minas Gerais, Brazil.

MZUSP--Museu de Zoologia da Universidade de Sao Paulo.

P--Field catalogue of Yves Sbalqueiro.

UFMG--Colecao de Mamiferos, Universidade Federal de Minas Gerais.

UFRGS--Colecao de Mamiferos, Universidade Federal de Rio Grande do Sul.

Localities

1. Brazil, Minas Gerais, Lagoa Santa, Lapa da Serra das Abelhas (~19[degrees]37'S, 43[degrees]53'W; exact locality coordinates unknown); Cerrado (type locality of Habrothrix angustidens, see Winge 1887).

2. Brazil, Minas Gerais, Simonesia, Mata do Sossego (20[degrees]7'S, 42[degrees]1'W, 575 m); Atlantic Forest--humid mountain forest, secondary forest (MN 35910).

3. Brazil, Espirito Santo, Ibitirama, Parque Nacional do Caparao (20[degrees]29'S, 41[degrees]43'W, 970 to 2890 m), including Pedra Rocha trapping station listed by Hershkovitz (1998) and Bonvicino et al. (2002) and Arrozal, Segredo, and Terreirao included by us (this paper); specimens housed at MN and FMNH; Atlantic Forest--mountain field, mountain scrub, humid mountain forest, secondary forest.

4. Brazil, Minas Gerais, Alto do Caparao, Parque Nacional do Caparao (20[degrees]26'10.4"S, 41[degrees]48'2.8"W, 970 to 2890 m) including Arrozal, Cachoeira Bonita, Centro de Visitantes, Pico da Bandeira, Segredo, Terreirao, Tronqueira, Vale Encantado, and Vale Verde trapping stations listed by Hershkovitz (1998) and Bonvicino et al. (2002) and Alfa, Beta, and Casa de Julio included by us (this paper); specimens housed at MN and FMNH; Atlantic Forest--mountain field, mountain scrub, humid mountain forest, secondary forest.

5. Brazil, Espirito Santo, Castelinho (20[degrees]31'S, 40[degrees]59'W, 1200 m); Atlantic Forest--humid mountain forest, secondary forest (MN 32631).

6. Brazil, Minas Gerais, Fervedouro, Parque Estadual da Serra do Brigadeiro, Fazenda da Neblina (20[degrees]40'0"S, 42[degrees]31'15"W, 1400 m); Atlantic Forest--mountain field, mountain scrub, humid mountain forest, secondary forest (MZUFV 1220).

7. Brazil, Minas Gerais, Tombos, Mata do Banco (20[degrees]56'28"S, 42[degrees]06'28"W, 467 m); Atlantic Forest--humid mountain forest (MZUFV 1900).

8. Brazil, Minas Gerais, Posses (21[degrees]41'S, 46[degrees]10'W, 1117 m); Atlantic Forest--humid mountain forest (UFMG 1855).

9. Brazil, Rio de Janeiro, Santa Maria Magdalena, Parque Estadual do Desengano (21[degrees]45'S, 41[degrees]41'W, 1425 m); Atlantic Forest--mountain field, mountain scrub, humid mountain forest (Modesto et al. 2008).

10. Brazil, Sao Paulo, Serra da Fartura, Sao Joao da Boa Vista (21[degrees]55'S, 46[degrees]43'W, 1142 m); Atlantic Forest--humid mountain forest (Moraes et al. 2003).

11. Brazil, Minas Gerais, Itamonte, Parque Nacional de Itatiaia, Brejo da Lapa (22[degrees]20'54.4"S, 44[degrees]41'38.2"W, 2100 m); Atlantic Forest--humid mountain forest with Araucaria (MN 48027).

12. Brazil, Rio de Janeiro, Visconde de Maua, Fazenda Marimbondo (22[degrees]21'38.5"S, 44[degrees]34'14.6"W, 1570 m); Atlantic Forest--humid mountain forest (MN 69804).

13. Brazil, Rio de Janeiro, Nova Friburgo, Tres Picos, Salinas (22[degrees]22'12"S, 42[degrees]30'32"W, 1380 m); Atlantic Forest--humid mountain forest (MN 80379).

14. Brazil, Rio de Janeiro, Itatiaia, Parque Nacional de Itatiaia: several localities including Abrigo Rebocas (22[degrees]23'07.5"S, 44[degrees]40'43.93"W, 2395 m; MN 69680), Piscina Maromba (22[degrees]26'S, 44[degrees]37'W, 1170 m; MN 69803), and Retiro de Ramos, 19 km from Parque Nacional de Itatiaia main house (exact locality coordinates unknown; type locality of Akodon serrensis leucogula); Atlantic Forest--humid mountain forest. The following sigmodontines also taken here: A. montensis, Akodonparanaensis, Brucepattersonius sp., Delomys altimontanus, D. dorsalis, D. sublineatus, O. nigripes, and Thaptomys nigrita.

15. Brazil, Rio de Janeiro, Nova Friburgo, Debossan, Sitio Xitaca (22[degrees]26'S, 42[degrees]32'W, 1010 m); Atlantic Forest--humid mountain forest (MN 35912). C. angustidens was obtained together with the following sigmodontines: Akodon montensis, Delomys sublineatus, Oligoryzomys nigripes, and Sooretamys angouya.

16. Brazil, Rio de Janeiro, Teresopolis, Parque Nacional da Serra dos Orgaos, Base da Pedra do Sino (22[degrees]27'34"S, 43[degrees]01'40"W, 2100 m); Atlantic Forest--Mountain field, mountain scrub, humid mountain forest (MN 69806).

17. Brazil, Rio de Janeiro, Cachoeiras de Macacu, Parque Nacional dos Tres Picos (22[degrees]27'45"S, 42[degrees]39'11"W, 1300 m); Atlantic Forest--humid mountain forest (MN 71942).

18. Brazil, Rio de Janeiro, Teresopolis, Parque Nacional da Serra dos Orgaos, Vale das Antas (22[degrees]27'50"S, 43[degrees]02'33"W, 1950 m); Atlantic Forest--Mountain field, mountain scrub (MN 69807). The following sigmodontines also taken here: Brucepattersonius sp., Delomys dorsalis, O. nigripes, Oxymycterus judex, and Thaptomys nigrita.

19. Brazil, Minas Gerais, Passa Quatro, Fazenda do Itaguare (22[degrees]28'S, 45[degrees]05'W, 1500 m) Atlantic Forest--humid mountain forest (UFMG 1854).

20. Brazil, Sao Paulo, Campos do Jordao, Parque Estadual de Campos do Jordao (22[degrees]44'22"S, 45[degrees]35'29"W, 1628 m); Atlantic Forest--humid mountain forest with Araucaria (CJ 5).

21. Brazil, Sao Paulo, Sao Jose do Barreiro, Parque Nacional da Bocaina (22[degrees]50'S, 44[degrees]41'W, 1400 m); Atlantic Forest--humid mountain forest (MN 69805).

22. Brazil, Rio de Janeiro, Paraty, Parque Nacional da Bocaina, RJ-165 road (23[degrees]11'54"S, 44[degrees]50'38"W, 1120 m); Atlantic Forest--humid mountain forest (MN 77791).

23. Brazil, Parana, Morretes, Represa de Guaricana (23[degrees]36'S, 49[degrees]04'W, 941 m) Atlantic Forest--humid mountain forest with Araucaria (MZUSP 29128).

24. Brazil, Sao Paulo, Salesopolis, Estacao Ecologica Boraceia (23[degrees]38'00"S, 45[degrees]52'00"W, 870 m); Atlantic Forest--humid mountain forest (MZUSP 9469).

25. Brazil, Sao Paulo, Sao Paulo (23[degrees]43'S, 46[degrees]43'W, 780 m); Atlantic Forest--humid mountain forest (MZUSP 6410).

26. Brazil, Sao Paulo, Paranapiacaba (23[degrees]46'41"S, 46[degrees]18'16"W, 820 m) Atlantic Forest --humid mountain forest (MZUSP 1796).

27. Brazil, Sao Paulo, Capao Bonito, Fazenda Intervales (24[degrees]20'00"S, 48[degrees]25'00"W, 700 m) Atlantic Forest--humid mountain forest (MZUSP 27226).

28. Brazil, Parana, Curitiba, Quatro Barras (25[degrees]21'56"S, 49[degrees]04'37"W, 936 m); Atlantic Forest--humid mountain forest with Araucaria (Rabelo 2007; P 828).

29. Brazil, Parana, Curitiba, Sao Jose dos Pinhais (25[degrees]26'S, 49[degrees]00'W, 1024 m); Atlantic Forest--humid mountain forest with Araucaria (Rabelo 2009).

30. Brazil, Parana, Piraquara, Roca Nova (25[degrees]26'30"S, 49[degrees]00'51"W, 905 m); Atlantic Forest--humid mountain forest (type locality of Akodon serrensis, see Thomas 1902; P 888).

31. Brazil, Parana, Piraquara, Mananciais da Serra (25[degrees]29'16.35"S, 45[degrees]58'32.2"W, 1117 m); Atlantic Forest--humid mountain forest with Araucaria (MN 78416).

32. Brazil, Parana, Sao Jose dos Pinhais, Guaricana (25[degrees]32'05"S, 49[degrees]12'23"W, 906 m); Atlantic Forest--humid mountain forest with Araucaria (P 108).

33. Brazil, Parana, Tijucas do Sul, Fazenda Panagro (25[degrees]57'14"S, 49[degrees]16'13"W, 1117 m); Atlantic Forest--originally sub-tropical forests of Auracaria augustifolia; today forests are reduced to small patches forming mosaics with agriculture and stockbreeding areas (Barros-Battesti et al. 1998; P 566).

34. Argentina, Misiones, "rio San Antonio, 32 km al norte de Bernardo de Irigoyen": from this locality [ca. 25[degrees]58'S, 53[degrees]10'W, 400 m], was collected 1 specimen by Harold Cleveland on 4 August 1971 and housed at the Coleccion de Mamiferos del IADIZA with the number M-00677 (Justo and De Santis 1977:47). This material was the base for the first reference of the species in Argentina, but subsequently criticized and discarded by Galliari et al. (1996:46), Pardinas et al. (2003:139), and Pereira et al. (2005:84) arguing measurement inconsistencies or a misidentification in favor to Thaptomys or the species of the cursor group of Akodon. Since the voucher specimen is loss from IADIZA collections (R. Ojeda, pers. comm. 2010), any inference about their identity is weak. However, is interesting to note that the information offered by Justo and De Santis (1977) regarding coloration and cranial morphology totally agrees with which is known for C. angustidens Argentinean specimens. More indeed, it was obtained in the Araucaria district, a typical habitat of this rodent in Brazil. In this context we consider here to resurrect this record as valid.

35. Argentina, Misiones, Reserva Privada de Vida Silvestre Urugua-i (25[degrees]59'S, 54[degrees]05'W; Pereira et al. 2005:83): a single specimen (MACN 22246) was recorded after an effort of 1,565 trap-nights in primary forest (ca. 300 m) belonging to the districts of "Laurel" and "Palo Rosa" (sensu Martinez-Crovetto 1963). The following sigmodontines also taken here: Akodon sp. (including A. montensis), Brucepattersonius sp., Delomys dorsalis, Nectomys squamipes, Oligoryzomys nigripes, Oxymycterus misionalis, Euryoryzomys russatus, and Sooretamys angouya.

36. Brazil, Parana, General Carneiro (26[degrees]25'S, 51[degrees]19'W, 1101 m); Atlantic Forest (Raboni et al. 2012).

37. Brazil, Santa Catarina, Reserva Biologica de Sassafras, Doutor Pedrinho (26[degrees]42'S, 49[degrees]40'W, 950 m); Atlantic Forest--"Floresta Ombofila Mista" (Testoni et al. 2012).

38. Argentina, Misiones, Provincial Route 2, 6 km NE Arroyo Paraiso (27[degrees]12'47.7"S, 54[degrees]01'59.9"W, 312 m): a single specimen (CNP 449) was obtained in secondary Atlantic Forest. The animal is an adult female and was trapped by Rosario Robles on April 24, 2007 (original number LTU 372).

39. Brazil, Santa Catarina, Rancho Queimado, Alto da Boa Vista (27[degrees]42'S, 49[degrees]09'W, 1200 m); Atlantic Forest--"Floresta Ombrofila Mista," edges of forest fragments, near high-altitude grasslands (Testoni et al. 2012).

40. Brazil, Santa Catarina, Campo Belo do Sul, Fazenda Gateados (27[degrees]58'S, 50[degrees]49'W, 1000 m); Atlantic Forest--"Floresta Ombrofila Mista" (Testoni et al. 2012).

41. Brazil, Santa Catarina, Urubici, Parque Nacional de Sao Joaquim, Fazenda Caiambora (28[degrees]01'S, 49[degrees]36'W, 1136 m); Atlantic Forest--humid mountain forest with Araucaria ((Goncalves et al. 2007).

42. Brazil, Rio Grande do Sul, Cambara do Sul, Parque Nacional da Serra Geral, Campo Limpo do Arroio do Segredo, Canion Fortaleza (29[degrees]04'17.4"S, 49[degrees]59'24.5"W, 1000 m); Atlantic Forest--humid mountain forest with Araucaria (MN 78550).

43. Brazil, Rio Grande do Sul, Sao Francisco de Paula, Centro de Pesquisas e Conservacao da Natureza Pro-Mata (29[degrees]26'53"S, 50[degrees]35'01"W, 900 m); Atlantic Forest--ecotone between "Campos de Altitude e Floresta Ombrofila Mista no Planalto das Araucarias" (UFRGS 2550-UFRGS 2558).

44. Brazil, Rio Grande do Sul, Sao Francisco de Paula, Centro de Pesquisas e Conservacao da Natureza Pro-Mata--CPCN Pro-Mata (29[degrees]29'08.9"S, 50[degrees]12'38.7"W, 600 to 900 m), Ombrophilous Mixed Forest (Araucaria Forest; Abreu et al. 2014).

Literature cited

Abreu, M., A. U. Christoff, V. H. Valiati, and L. R. de Oliveira. 2014. New distribution records of Serra do Mar Grass Mouse Akodon serrensis Thomas, 1902 (Mammalia: Rodentia: Sigmodontinae) in the southernmost Brazil. Check List 10:655-659.

Barros-Battesti, D. M., M. Arzua, P. M. Linardi, J. R. Botelho, and I. J.

Sbalqueiro. 1998. Interrelationship between ectoparasites and wild rodents from Tijucas do Sul, State of Parana, Brazil. Memorias do Instituto Oswaldo Cruz 93:719-725.

Bonvicino, C. R., S. M. Lindbergh, and L. S. Maroja. 2002. Small non-flying mammals from conserved and altered areas of Atlantic Forest and Cerrado: comments on their potential use for monitoring environment. Brazilian Journal of Biology 62:765-774.

Galliari, C., U. F. J. Pardinas, and F. J. Goin. 1996. Lista comentada de los mamiferos argentinos. Mastozoologia Neotropical 3:39-61.

Gonsalves, P. R., P. Myers, J. Vilela, J., and J. A. Oliveira. 2007. Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the campos de altitude. Miscellaneous Publications, Museum of Zoology, University of Michigan 197:1-24.

Hershkovitz P. 1998. Report on some sigmodontine rodents collected in southeastern Brazil with descriptions of a new genus and six new species. Bonner Zoologische Beitrage 47:193-256.

Justo E. and L. de Santis. 1977. Akodon serrensis serrensis Thomas en la Argentina (Rodentia, Cricetidae). Neotropica 23:47-48.

Martinez-Crovetto, R. 1963. Esquema fitogeografico de la Provincia de Misiones (Argentina). Bonplandia 1:171-223.

Modesto, T. C., F. S. Pessoa, M. C. Enrici, N. Attias, T. Jordao-Nogueira, L. M. Costa, H. G. Albuquerque, and H. G. Bergallo. 2008. Mamiferos do Parque Estadual do Desengano, Rio de Janeiro, Brasil. Biota Neotropica 8:153-159.

Moraes, L. B., D. A. P. Bossi, and A. X. Linhares. 2003. Siphonaptera parasites of wild rodents and marsupials trapped in three mountain ranges of the Atlantic Forest in Southeastern Brazil. Memorias do Instituto Oswaldo Cruz 98:1071-1076.

Pardinas U. F. J., G. D'Elia, and S. Cirignoli. 2003. The genus Akodon (Muroidea: Sigmodontinae) in Misiones, Argentina. Mammalian Biology 68:129-143.

Pereira, J., P. Teta, N. Fracassi, A. Johnson, and P. Moreyra. 2005. Sigmodontinos (Rodentia, Cricetidae) de la reserve de vida silvestre Uurugua-i (Provincia de Misiones, Argentina), Con la confirmacion de la presencia de "Akodon" serrensis en la Argentina. Mastozoologia Neotropical 12:83-89.

Rabelo, G. P. 2007. O genero Akodon (Rodentia, Cricetidae)--principais mecanismos responsaveis pela variabilidade cariotipica e sua possivel implicado na distribuido das especies ocorrentes no estado do Parana. Monografia de Bacharelado em Ciencias Biologicas, Universidade Federal do Parana, Parana, Brazil.

Raboni, S.M., A. Delfraro, L. Borba, B. R. Teixeira, V. Stella, M. R. Araujo, S. Carstensen, G. Rubio, A. Maron, E. R. S. Lemos, P. S. D'Andrea, and C. N. D. Santos. 2012. Hantavirus infection prevalence in wild rodents and human antihantavirus serological profiles from different geographic areas of south Brazil. American Journal of Tropical Medicine and Hygiene 87:371-378.

Testoni, A.F., J. Fumis, S. L. Althoff, F. R. Tortato, and J. J. Cherem. 2012. Akodon serrensis Thomas, 1902 (Mammalia: Rodentia: Sigmodontinae): Records in Santa Catarina state, southern Brazil. Check List 8:1344-1346.

Thomas, O. 1902. On mammals from the Serra do Mar, Parana, collected by Mr. Alphonse Robert. Annals and Magazine of Natural History Series 7, 9:59-64.

Winge, H. 1887. Jordfundne og nulevende Gnavere (Rodentia) fra Lagoa Santa, Minas Geraes, Brasilien. E Museo Lundii, 1(3):1-178 + 18 plates.

S2. Study notes on Habrothrix angustidens and Akodon serrensis made by R. S. Voss in November, 2008.

Notes on Akodon serrensis Thomas, 1902

I examined the type (BMNH ???) and eight topotypes (BMNH ???, ZMUC 1257) of Akodon serrensis, consisting of skins and skulls collected at Ro9a Nova, Serra do Mar, between 930 and 1150 m above sea level by A. Robert in August and September of 1901. The skins are dark yellowish- or orangish-brown dorsally, with thick, soft fur; the ventral surface is washed with bright buff or tawny over dark-gray hair bases. Tails are dark, unicolored, and sparsely haired. The eyes are small, and the mystacial vibrissae are short, not extending posteriorly much beyond the base of the pinnae. Genal vibrissae are present.

The skull in dorsal view is characterized by a long, pointed rostrum flanked by shallow zygomatic notches; the frontal sinuses are inflated and the interorbital region is broad, with rounded supraorbital margins in young specimens (older animals develop small, sharp, convergent postorbital edges). The zygomatic arches are delicate, widest across the squamosal roots, and convergent anteriorly. The braincase is large, smooth, and globose. The zygomatic plate in lateral view has a straight anterior margin that is aligned vertically or slopes slightly backward; the origin of the superficial masseter is marked by a scar (not a tubercle) that is just below and slightly behind the anteroventral margin of the zygomatic plate. The carotid circulation is primitive, an alisphenoid strut is present, and the subsquamosal fenestra is large (but smaller than the postglenoid foramen). The incisive foramina are long (extending deeply between the M1 anterocones); the palate is broad and uncomplicated by keels or deep lateral grooves; and the mesopterygoid fossa extends anteriorly to or between the M3s. There are no large posterolateral palatal pits, just tiny foramina flanking the mesopterygoid fossa.

The mesopterygoid roof is completely bony or perforated by very narrow sphenopalatine openings. The auditory bullae are small and flask-shaped with broad bony eustacian tubes.

The upper incisors are narrow and opisthodont, with yellow-orange enamel bands. The molars are very narrow in proportion to their length, and retain little occlusal detail even in young animals, the cusps and lophs wearing rapidly away to dentine. The alveolus of the lower incisor is contained in a ridge, not a distinct process, on the lateral surface of the mandible behind the base of the coronoid process.

Notes on the type series of Habrothrix angustidens Winge, 1887

The type series of Habrothrix angustidens consists of subfossil cranial fragments and disassociated hemimandibles from several caves in the vicinity of Lagoa Santa; Winge's handwritten labels suggest that all were recovered from mineral sediments, not from Recent owl pellets. The caves from which specimens were collected include those that Lund called "Lapa Serra das Abelhas", "Lapa da Escrivania", "Lapa de Cerca Grande", and "Lapa da Quebra Chavelha." All of this material qualifies as syntypes because Winge did not designate a holotype. In order to more securely fix the application of the name angustidens, we designate the large cranial fragment that Winge illustrated (op. cit. plate II, fig. 9) as the lectotype, by which action all the remaining material become paralectotypes.

Altogether, this material (lectotype plus paralectotypes) preserves the entire upper and lower dentition, the left zygomatic plate, diastema, palate, interorbital region, and mandibles. We compared this material side-by-side with a complete topotypical cranium of Akodon serrensis (ZMUC 1257) and found these two taxa to be phenotypically indistinguishable. In addition to qualitative resemblances, the few measurements that we were able to take from the lectotype of angustidens all fall within the range of variation seen in the topotypic series of serrensis:
   Length of Diastema: 6.3 mm
   Length of Molars: 4.9 mm
   Breadth of M1: 1.2 mm
   Length of Incisive Foramina: 5.9 mm
   Breadth of Rostrum: 4.4 mm
   Breadth of Palatal Bridge: 2.6 mm
   Breadth of Zygomatic Plate: 2.2 mm
   Least Interorbital Breadth: 5.2 mm
   Depth of Incisors: 1.2 mm


The only possible taxonomic conclusion is that angustidens and serrensis are synonyms.

Robert S. Voss

4 November 2008
Measurements (mm) of the type series of Akodon serrensis (a)

                                  Minimum   Maximum   Mean   N

Length of Head and Body (b)       85        105       92     8
Length of Tail (b)                70        85        78     8
Hind Foot (including claws) (c)   23        25        24     8
Ear (b)                           17        18        17     8
Condylo-incisive Length           22.5      24.8      23.7   8
Length of Diastema                6.3       7.5       6.8    9
Length of Molars                  4.8       5.2       4.9    9
Breadth of M1                     1.1       1.2       1.2    9
Length of Incisive Foramina       5.5       6.1       5.8    9
Breadth of Rostrum                4.2       4.7       4.5    9
Breadth of Palatal Bridge         2.5       3.3       2.8    9
Breadth of Zygomatic Plate        2.2       2.6       2.4    9
Least Interorbital Breadth        5.2       5.6       5.4    9
Breadth of Braincase              11.7      12.7      12.2   9
Depth of Incisor                  1.1       1.3       1.2    9
Length of Orbital Fossa           7.7       8.4       8.0    9

(a) BMNH 3.7.1.66-3.7.1.73, ZMUC 1257.
(b) Measured by collector.
(c) Measured from dry skin.


S3.-Individual specimen scores projected onto principal components I and II extracted from the analysis of log-transformed values of five cranial and two dental variables of all age classes of Castoria angustidens nov. comb. Gray circles represent recent individuals; black circle corresponds to the lectotype of Habrothrix angustidens Winge (ZMK 1/1845:13246).

[GRAPHIC OMITTED]

Loadings of five cranial and two dental variables onto the first two principal components of Castoria angustidens nov. comb.
                                     Principal components

Variables                            First   Second

Length of diastema                   0.52    -0.19
Length of incisive foramina          0.44    -0.36
Crown length of maxillary toothrow   0.22     0.38
Breadth of first upper molar         0.36    -0.21
Breadth of rostrum                   0.37     0.35
Interorbital breadth                 0.25     0.70
Breadth of zygomatic plate           0.40    -0.14


S4.-External appearance of Castoria angustidens nov. comb. based on the skin of the holotype of Akodon serrensis Thomas, 1902 (BM 3.7.1.69) in dorsal (top), ventral (middle), and left lateral (bottom) view.

[ILLUSTRATION OMITTED]

S5.-Gastric morphology of Castoria angustidens nov. comb. based on CNP 449 (Misiones, Argentina): diagram (above), field-photograph of the bisected specimen (below). Anatomical features indicated are: a, antrum; bf, bordering fold; c, corpus; e, posterior end of esophagus; ia, incisura angularis.

[ILLUSTRATION OMITTED]

[ILLUSTRATION OMITTED]

S6.-A) GTG-banding patterns of Castoria angustidens female karyotype, 2n = 46 and FN = 46. Inset, X and Y chromosomes from the male individual. B) Male C. angustidens metaphase after hybridization using double probe (Akodon paranaensis 6 and 7). Whole painted chromosomes corresponding to A. paranaensis 6 and 7 on C. angustidens metaphase are indicated on the left. The painted chromosomes of C. angustidens are indicated on the DAPI-stained metaphase on the right. Asterisks indicate the 2 chromosomes of C. angustidens painted by A. paranaensis 7. C) Male Necromys lasiurus metaphase, 2n = 34 and FN = 34 after hybridization using double probe (A. paranaensis 6 and 7). Painted segments and chromosomes corresponding to A. paranaensis genome on N. lasiurus metaphase are indicated on the left. The painted chromosome and segments of N. lasiurus are indicated on the DAPI-stained metaphase on the right. Asterisks indicate the 2 chromosomes of N. lasiurus painted by A. paranaensis 7. The identification of chromosomes was based on GTG-banding patterning. Painted segments are pink.

[ILUSTRACION OMITIR]

S7.-Ventral view of the skulls of the holotypes of Akodon pervalens Thomas, 1925 (to the left; BM 25.2.1.55; photograph thanks to British Museum of Natural History, [C] The Natural History Museum, London) and Akodon serrensis Thomas, 1902 (to the right; BM 3.7.1.69; photograph taken by A. Bezerra). Main differences are, among others, the broad rostrum (pervalens) vs. the acute rostrum (serrensis); the foraminal margins resembling parentheses (pervalens) vs. the constricted anterior portion of the incisive foramina (serrensis); the smaller braincase (pervalens) vs. the inflated and larger braincase (serrensis).

[ILLUSTRATION OMITTED]

S8.-Montane forest with Araucaria at about 2100 m, Itamonte, Brazil inhabited by Castoria angustidens nov. comb. Photograph taken by L. Geise.

[ILLUSTRATION OMITTED]

S9.-Latitude and elevation for collection localities of Castoria angustidens nov. comb. The plotted points are listed in the gazetteer (Supporting Information S1).

[GRAPHIC OMITTED]

S10.-Lectotype of Castoria angustidens nov. comb. (ZMK 1/1845:13246) from Lapa da Escrivania Nr. 5: right lateral (a), left lateral (b), ventral (c) and dorsal (d) view of the skull (scale = 5 mm) and upper and lower right toothrows (e) from epoxy casts. The figure in (f) depicts the original label handwritten by H. Winge with the indication that the skull fragment was illustrated -"tegnet" in Danish; the original illustration of Habrothrix angustidens from Winge (1887:II, fig. 2) is shown on (g).

[ILLUSTRATION OMITTED]

Ulyses F. J. Pardinas (1), Lena Geise (2), Karen Ventura (3), and Gisele Lessa (4)

(1) Instituto de Diversidad y Evolucion Austral (IDEAus, CONICET), CC 128, 9120 Puerto Madryn, Chubut, Argentina. [Correspondence: <ulyses@cenpat-conicet.gob.ar>].

(2) Laboratorio de Mastozoologia, Departamento de Zoologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, Maracana, 20550-900 Rio de Janeiro, Brazil.

(3) Departamento de Genetica e Biologia Evolutiva, Instituto de Biociencias, Universidade de Sao Paulo, Rua do Matao 277, 05508-090 Sao Paulo-SP and Instituto de Recursos Naturais, Universidade Federal de Itajuba, Avenida BPS 1303, 37500-903 Itajuba, Minas Gerais, Brazil.

(4) Museu de Zoologia, Departamento de Biologia Animal, Universidade Federal de Vinosa, 36571-000 Vinosa, Minas Gerais, Brazil.
Table 1

Selected measurements (in mm) of the lectotype of Habrothrix
angustidens (ZMK 1-1845:13246), the type series of Akodon serrensis
(BMNH 3.7.1.66-BMNH 3.7.1.73, ZMK 1257; mean, minimum--maximun and
sample size in parenthesis), and the holotype of Akodon serrensis
leucogula (MN 2513).

                              H. angustidens        A. serrensis

Length of head and body (a)         --            92, 85 - 105 (8)
Length of tail (a)                  --             78, 70 - 85 (8)
Hind foot with claws (b)            --             24, 23 - 25 (8)
Eara                                --             17, 17 - 18 (8)
Condylo-incisive length             --          23.7, 22.5 - 24.8 (8)
Length of diastema                  6.3          6.8, 6.3 - 7.5 (9)
Length of upper molars              4.9          4.9, 4.8 - 5.2 (9)
Breadth of M1                       1.2          1.2, 1.1 - 1.2 (9)
Length of incisive foramina         5.9          5.8, 5.5 - 6.1 (9)
Breadth of rostrum                  4.4          4.5, 4.2 - 4.7 (9)
Breadth of palatal bridge           2.6          2.8, 2.5 - 3.3 (9)
Breadth of zygomatic plate          2.2          2.4, 2.2 - 2.6 (9)
Least interorbital breadth          5.2          5.4, 5.2 - 5.6 (9)
Breadth of braincase                --          12.2, 11.7 - 12.7 (9)
Depth of incisor                    1.2          1.2, 1.1 - 1.3 (9)
Length of orbital fossa             --           8.0, 7.7 - 8.4 (9)

                              A. s. leucogula

Length of head and body (a)         105
Length of tail (a)                   73
Hind foot with claws (b)           24 (a)
Eara                                 --
Condylo-incisive length             25.8
Length of diastema                  7.1
Length of upper molars              4.6
Breadth of M1                       1.6
Length of incisive foramina         5.6
Breadth of rostrum                  4.6
Breadth of palatal bridge            --
Breadth of zygomatic plate          2.7
Least interorbital breadth          5.3
Breadth of braincase                11.1
Depth of incisor                     --
Length of orbital fossa             8.2

(a) Measured by collector.

(b) Measured from dry skin.

Table 2

Descriptive statistics (in mm; mean [+ or -] standard deviation,
range, and sample size in parenthesis) for 2 samples of adult
individuals of Castoria angustidens nov.comb., from Brazil (see
Supplementary Material S1 for additional data about these
localities); PE = Parque Estadual; PN = Parque Nacional.

                                    Fazenda da Neblina, PE
                                    da Serra do Brigadeiro

                                          females

Length of head and body             98.70 [+ or -] 26.90
Length of tail                      89.80 [+ or -] 23.38
Length of hind foot with claw       25.57 [+ or -] 6.31
Length of hind foot without claw    23.29 [+ or -] 5.51
Length of ear                       17.20 [+ or -] 2.58
Weight                              29.67 [+ or -] 10.42
Breadth across M1s                   5.67 [+ or -] 1.26
Breadth across occipital condyles    6.55 [+ or -] 1.01
Breadth of braincase                11.68 [+ or -] 0.58
Breadth of incisive foramina         2.13 [+ or -] 2.27
Breadth of M1                        1.25 [+ or -] 2.53
Breadth of rostrum                   5.09 [+ or -] 1.44
Breadth of zygomatic plate           2.82 [+ or -] 2.09
Condylo-incisive length             25.39 [+ or -] 4.53
Height of skull                      8.26 [+ or -] 0.54
Height of mandible                   6.28 [+ or -] 1.11
Least interorbital breadth           5.54 [+ or -] 1.30
Length of bulla                      4.77 [+ or -] 1.52
Length of diastema                   7.26 [+ or -] 0.87
Length of incisive foramina          5.96 [+ or -] 1.21
Length of mandible                  14.02 [+ or -] 1.22
Length of orbital fossa              8.52 [+ or -] 0.54
Length of palatal bridge             4.32 [+ or -] 1.66
Length of rostrum                   11.06 [+ or -] 0.60
Length of maxillary molar row        4.96 [+ or -] 1.47
Zygomatic breadth                   14.57 [+ or -] 2.14

                                    Fazenda da Neblina, PE
                                    da Serra do Brigadeiro

                                          females

Length of head and body             84.00 - 113.00 (10)
Length of tail                      83.00 - 95.00 (10)
Length of hind foot with claw        24.00 - 28.00 (7)
Length of hind foot without claw     22.00 - 25.00 (7)
Length of ear                       14.00 - 20.00 (10)
Weight                               19.00 - 38.00 (6)
Breadth across M1s                   5.36 - 5.99 (10)
Breadth across occipital condyles    6.23 - 6.82 (10)
Breadth of braincase                11.11 - 12.15 (10)
Breadth of incisive foramina         1.95 - 2.39 (10)
Breadth of M1                        1.14 - 1.37 (10)
Breadth of rostrum                   4.69 - 5.62 (10)
Breadth of zygomatic plate           2.45 - 3.30 (10)
Condylo-incisive length             23.51 - 27.24 (10)
Height of skull                      7.94 - 8.69 (10)
Height of mandible                   5.67 - 6.66 (10)
Least interorbital breadth           5.21 - 5.86 (10)
Length of bulla                      4.55 - 5.06 (10)
Length of diastema                   6.76 - 7.98 (10)
Length of incisive foramina          5.45 - 6.66 (10)
Length of mandible                  13.34 - 14.86 (10)
Length of orbital fossa              8.07 - 9.29 (10)
Length of palatal bridge             3.65 - 4.55 (10)
Length of rostrum                   10.00 - 12.13 (10)
Length of maxillary molar row        4.41 - 5.16 (10)
Zygomatic breadth                   13.60 - 15.35 (10)

                                    Fazenda da Neblina, PE
                                    da Serra do Brigadeiro

                                           males

Length of head and body             96.67 [+ or -] 27.88
Length of tail                      83.33 [+ or -] 23.15
Length of hind foot with claw       25.50 [+ or -] 7.07
Length of hind foot without claw    23.33 [+ or -] 6.26
Length of ear                       16.71 [+ or -] 3.30
Weight                              28.50 [+ or -] 9.82
Breadth across M1s                   5.58 [+ or -] 1.06
Breadth across occipital condyles    6.49 [+ or -] 0.78
Breadth of braincase                11.67 [+ or -] 1.19
Breadth of incisive foramina         2.09 [+ or -] 2.09
Breadth of M1                        1.27 [+ or -] 2.33
Breadth of rostrum                   4.99 [+ or -] 1.25
Breadth of zygomatic plate           2.56 [+ or -] 1.97
Condylo-incisive length             24.74 [+ or -] 4.83
Height of skull                      8.22 [+ or -] 0.27
Height of mandible                   6.28 [+ or -] 0.86
Least interorbital breadth           5.47 [+ or -] 1.08
Length of bulla                      4.79 [+ or -] 1.03
Length of diastema                   7.02 [+ or -] 0.67
Length of incisive foramina          5.75 [+ or -] 1.03
Length of mandible                  13.49 [+ or -] 1.45
Length of orbital fossa              8.26 [+ or -] 0.30
Length of palatal bridge             4.39 [+ or -] 1.40
Length of rostrum                   10.71 [+ or -] 0.78
Length of maxillary molar row        5.02 [+ or -] 1.21
Zygomatic breadth                   14.21 [+ or -] 1.99

                                    Fazenda da Neblina, PE
                                    da Serra do Brigadeiro

                                          males

Length of head and body             83.00 - 116.00 (9)
Length of tail                      74.00 - 95.00 (9)
Length of hind foot with claw       24.00 - 29.00 (6)
Length of hind foot without claw    22.00 - 26.00 (6)
Length of ear                       16.00 - 18.00 (7)
Weight                              21.00 - 39.00 (6)
Breadth across M1s                   5.24 - 5.97 (9)
Breadth across occipital condyles    6.16 - 6.84 (9)
Breadth of braincase                11.31 - 12.32 (8)
Breadth of incisive foramina         1.77 - 2.25 (9)
Breadth of M1                        1.12 - 1.42 (9)
Breadth of rostrum                   4.50 - 5.55 (9)
Breadth of zygomatic plate           1.76 - 2.97 (9)
Condylo-incisive length             23.28 - 26.36 (9)
Height of skull                      8.00 - 8.40 (9)
Height of mandible                   5.80 - 6.67 (9)
Least interorbital breadth           5.24 - 5.70 (9)
Length of bulla                      4.45 - 5.07 (8)
Length of diastema                   6.56 - 7.52 (9)
Length of incisive foramina          5.39 - 6.22 (9)
Length of mandible                  12.47 - 14.06 (9)
Length of orbital fossa              7.92 - 8.58 (9)
Length of palatal bridge             4.02 - 4.72 (9)
Length of rostrum                    9.54 - 11.69 (9)
Length of maxillary molar row        4.69 - 5.32 (9)
Zygomatic breadth                   13.52 - 14.69 (8)

                                    Vale das Antas, PN da
                                      Serra dos Orgaos

                                           females

Length of head and body             100.03 [+ or -] 14.09
Length of tail                       84.10 [+ or -] 12.30
Length of hind foot with claw        25.77 [+ or -] 3.30
Length of hind foot without claw     23.87 [+ or -] 3.46
Length of ear                        15.80 [+ or -] 3.90
Weight                               24.48 [+ or -] 4.13
Breadth across M1s                    5.74 [+ or -] 3.95
Breadth across occipital condyles     6.55 [+ or -] 3.81
Breadth of braincase                 11.48 [+ or -] 2.89
Breadth of incisive foramina          2.17 [+ or -] 4.61
Breadth of M1                         1.30 [+ or -] 4.77
Breadth of rostrum                    4.99 [+ or -] 4.10
Breadth of zygomatic plate            2.76 [+ or -] 4.51
Condylo-incisive length              25.46 [+ or -] 0.81
Height of skull                       8.25 [+ or -] 3.49
Height of mandible                    6.40 [+ or -] 3.59
Least interorbital breadth            5.38 [+ or -] 4.02
Length of bulla                       4.86 [+ or -] 4.12
Length of diastema                    7.39 [+ or -] 3.66
Length of incisive foramina           5.87 [+ or -] 3.93
Length of mandible                   13.85 [+ or -] 2.18
Length of orbital fossa               8.24 [+ or -] 3.49
Length of palatal bridge              4.53 [+ or -] 4.18
Length of rostrum                    11.19 [+ or -] 2.09
Length of maxillary molar row         4.99 [+ or -] 4.09
Zygomatic breadth                    14.30 [+ or -] 1.80

                                    Vale das Antas, PN da
                                      Serra dos Orgaos

                                           females

Length of head and body              84.00 - 116.00 (31)
Length of tail                       60.00 - 96.00 (29)
Length of hind foot with claw        16.00 - 31.50 (30)
Length of hind foot without claw     14.00 - 29.00 (30)
Length of ear                        11.00 - 22.00 (30)
Weight                               17.00 - 36.00 (30)
Breadth across M1s                    5.42 - 6.09 (27)
Breadth across occipital condyles     5.95 - 7.00 (27)
Breadth of braincase                 11.03 - 12.01 (27)
Breadth of incisive foramina          1.85 - 2.49 (27)
Breadth of M1                         1.18 - 1.46 (27)
Breadth of rostrum                    4.12 - 5.58 (27)
Breadth of zygomatic plate            2.28 - 3.29 (27)
Condylo-incisive length              23.47 - 27.47 (27)
Height of skull                       7.84 - 8.59 (27)
Height of mandible                    5.78 - 6.94 (25)
Least interorbital breadth            5.05 - 5.94 (27)
Length of bulla                       4.47 - 5.42 (27)
Length of diastema                    6.60 - 8.20 (27)
Length of incisive foramina           5.34 - 6.53 (27)
Length of mandible                   13.11 - 14.77 (25)
Length of orbital fossa               7.73 - 8.78 (27)
Length of palatal bridge              3.74 - 5.07 (27)
Length of rostrum                    10.23 - 12.16 (21)
Length of maxillary molar row         4.70 - 5.28 (27)
Zygomatic breadth                    13.60 - 15.06 (23)

                                    Vale das Antas, PN da
                                      Serra dos Orgaos

                                            males

Length of head and body             102.20 [+ or -] 12.20
Length of tail                       85.10 [+ or -] 10.18
Length of hind foot with claw        25.36 [+ or -] 2.60
Length of hind foot without claw     23.18 [+ or -] 3.05
Length of ear                        16.81 [+ or -] 4.42
Weight                               25.47 [+ or -] 7.54
Breadth across M1s                    5.66 [+ or -] 4.73
Breadth across occipital condyles     6.49 [+ or -] 4.49
Breadth of braincase                 11.42 [+ or -] 3.66
Breadth of incisive foramina          2.09 [+ or -] 5.32
Breadth of M1                         1.30 [+ or -] 5.45
Breadth of rostrum                    5.03 [+ or -] 4.84
Breadth of zygomatic plate            2.75 [+ or -] 5.21
Condylo-incisive length              25.47 [+ or -] 1.54
Height of skull                       8.24 [+ or -] 4.30
Height of mandible                    6.38 [+ or -] 4.40
Least interorbital breadth            5.34 [+ or -] 4.78
Length of bulla                       4.79 [+ or -] 4.88
Length of diastema                    7.39 [+ or -] 4.45
Length of incisive foramina           5.87 [+ or -] 4.70
Length of mandible                   13.90 [+ or -] 3.13
Length of orbital fossa               8.31 [+ or -] 4.29
Length of palatal bridge              4.58 [+ or -] 4.92
Length of rostrum                    10.98 [+ or -] 3.54
Length of maxillary molar row         4.98 [+ or -] 4.84
Zygomatic breadth                    14.28 [+ or -] 2.81

                                    Vale das Antas, PN da
                                      Serra dos Orgaos

                                            males

Length of head and body              87.00 - 119.00 (40)
Length of tail                       70.00 - 101.00 (39)
Length of hind foot with claw        22.00 - 28.00 (39)
Length of hind foot without claw     19.00 - 25.00 (40)
Length of ear                        11.00 - 23.00 (40)
Weight                               15.00 - 60.00 (38)
Breadth across M1s                    5.19 - 6.27 (34)
Breadth across occipital condyles     6.07 - 7.41 (33)
Breadth of braincase                 10.90 - 11.91 (33)
Breadth of incisive foramina          1.76 - 2.33 (34)
Breadth of M1                         1.14 - 1.43 (34)
Breadth of rostrum                    4.40 - 5.66 (34)
Breadth of zygomatic plate            2.40 - 3.06 (34)
Condylo-incisive length              23.26 - 26.76 (33)
Height of skull                       7.85 - 8.61 (34)
Height of mandible                    5.77 - 6.94 (32)
Least interorbital breadth            4.81 - 5.76 (34)
Length of bulla                       4.23 - 5.27 (34)
Length of diastema                    6.61 - 8.00 (34)
Length of incisive foramina           4.97 - 6.44 (34)
Length of mandible                   13.14 - 14.79 (32)
Length of orbital fossa               7.74 - 8.92 (34)
Length of palatal bridge              4.15 - 6.25 (34)
Length of rostrum                     9.17 - 11.91 (31)
Length of maxillary molar row         4.73 - 5.28 (34)
Zygomatic breadth                    13.54 - 15.18 (30)

Table 3

Morphological comparisons of selected traits among Castoria gen. nov.
and other related sigmodontines of the Akodon Division.

Characters                                     Castoria

Head and body length as % total length           ~ 85%
Countershading                                   weak
Rostrum                                     long and narrow
Interorbital region                              broad
Frontals                                    convergent with
                                             sharp margins
Free upper border of zygomatic plate              yes
Premaxillary process                     > 1/2 of the incisive
                                            foramen length
Alisphenoid strut                               present
Middle lacerate foramen                          open
Subsquamosal [ssf] / postglenoid [pgf]         ssf ~ pgf
  fenestrae size
Capsular process                                absent
Molar design main cusps                        opposite
Anteromedian flexus                             absent
Procingulum m1                                compressed
m2 / m3 in length                               m2 ~ m3
Gall bladder                                    present

Characters                                      Akodon
                                            (cursor group)

Head and body length as % total length           ~ 80%
Countershading                                 moderate
Rostrum                                     long and narrow
Interorbital region                            moderate
Frontals                                   "hourglass," with
                                            rounded margins
Free upper border of zygomatic plate              yes
Premaxillary process                     < 1/2 of the incisive
                                            foramen length
Alisphenoid strut                               present
Middle lacerate foramen                          open
Subsquamosal [ssf] / postglenoid [pgf]         ssf ~ pgf
  fenestrae size
Capsular process                                absent
Molar design main cusps                        alternate
Anteromedian flexus                             present
Procingulum m1                              not compressed
m2 / m3 in length                               m2 > m3
Gall bladder                               present or absent

Characters                                     Deltamys

Head and body length as % total length           ~ 85%
Countershading                                   weak
Rostrum                                    short and narrow
Interorbital region                             narrow
Frontals                                   "hourglass," with
                                            rounded margins
Free upper border of zygomatic plate              no
Premaxillary process                     > 1/2 of the incisive
                                            foramen length
Alisphenoid strut                               absent
Middle lacerate foramen                          close
Subsquamosal [ssf] / postglenoid [pgf]         ssf ~ pgf
  fenestrae size
Capsular process                                absent
Molar design main cusps                        opposite
Anteromedian flexus                             present
Procingulum m1                                compressed
m2 / m3 in length                               m2 > m3
Gall bladder                                    present

Characters                                       Necromys
                                            (excluding amoenus
                                                and urichi)

Head and body length as % total length           ~ 55-60%
Countershading                                   moderate
Rostrum                                       short and broad
Interorbital region                                broad
Frontals                                      convergent with
                                              beaded margins
Free upper border of zygomatic plate                yes
Premaxillary process                       < 1/2 of the incisive
                                              foramen length
Alisphenoid strut                                 present
Middle lacerate foramen                            open
Subsquamosal [ssf] / postglenoid [pgf]           ssf < pgf
  fenestrae size
Capsular process                                  present
Molar design main cusps                          opposite
Anteromedian flexus                               absent
Procingulum m1                                not compressed
m2 / m3 in length                        m2 [much greater than] m3
Gall bladder                                 present or absent

Characters                                       Thalpomys

Head and body length as % total length             ~ 60%
Countershading                                    strong
Rostrum                                       short and broad
Interorbital region                                broad
Frontals                                      convergent with
                                              ledged margins
Free upper border of zygomatic plate                yes
Premaxillary process                       < 1/2 of the incisive
                                              foramen length
Alisphenoid strut                                    ?
Middle lacerate foramen                            open
Subsquamosal [ssf] / postglenoid [pgf]           ssf ~ pgf
  fenestrae size
Capsular process                                  present
Molar design main cusps                          alternate
Anteromedian flexus                               present
Procingulum m1                                not compressed
m2 / m3 in length                        m2 [much greater than] m3
Gall bladder                                      present

Characters                                      Thaptomys

Head and body length as % total length            ~ 35%
Countershading                                     weak
Rostrum                                      short and broad
Interorbital region                               broad
Frontals                                     convergent with
                                             rounded margins
Free upper border of zygomatic plate                no
Premaxillary process                      > 1/2 of the incisive
                                              foramen length
Alisphenoid strut                                present
Middle lacerate foramen                           close
Subsquamosal [ssf] / postglenoid [pgf]   ssf [much less than] pgf
  fenestrae size
Capsular process                                 present
Molar design main cusps                         alternate
Anteromedian flexus                              present
Procingulum m1                                not compressed
m2 / m3 in length                                m2 > m3
Gall bladder                                      absent
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Article Details
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Author:Pardinas, Ulyses F.J.; Geise, Lena; Ventura, Karen; Lessa, Gisele
Publication:Mastozoologia Neotropical
Date:Jun 1, 2016
Words:18309
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