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Non-metric characters in two species of Sotalia (Gray, 1866) (Cetacea, Delphinidae)/Caracteres nao metricos nas duas especies de Sotalia (Gray, 1866).

1. Introduction

The genus Sotalia (Gray, 1866) was until recently considered monospecific, however recent molecular genetics (Cunha et al., 2005; Caballero et al., 2007), and geometric morphometric (Monteiro-Filho et al., 2002) studies revealed the existence of two species: the marine species Sotalia guianensis (P.J. van Beneden, 1864) (gray dolphin) and the riverine species Sotalia fluviatilis (Gervais, 1853) (tucuxi).

The marine species is broadly distributed along the tropical and subtropical Atlantic coast of South and Central America, having been recorded from Florianopolis, Santa Catarina, Brazil (27[degrees] 35' S and 48[degrees] 34' W) (Simoes-Lopes, 1988; Borobia, 1989) to Honduras (15[degrees] 58' N and 85[degrees] 42' W) (da Silva and Best, 1996). The riverine species is endemic to the Amazon Basin, occurring from Belem (at the mouth of the Amazon River), in Brazil, to the rivers of Peru, Colombia and Ecuador (Borobia et al., 1991, da Silva and Best, 1996).

Osteological descriptions for the genus Sotalia have been published by Miranda-Ribeiro (1936); Casinos et al. (1981); Borobia (1989); Menezes and SimoesLopes (1996); da Silva and Best (1996); Alves Junior and Monteiro-Neto (1999); Avila et al. (2002); Fettuccia and Simoes-Lopes (2004), Simoes-Lopes (2006). With the exception of Simoes-Lopes (2006), these studies were mainly based on traditional studies of morphometrics. There are no previous comparative studies using non-metric characteristics such as, for example, the comparison of forms or presence and absence of determined characters for this genus. Therefore, this study aims to compare the two species of the genus Sotalia using nonmetric characters.

2. Material and Methods

A total of 149 specimens were analysed from five distinct Brazilian states: Mammal Collection of National Institute for Amazonia Research (INPA), Manaus, Amazonas (AM); Emilio Goeldi Museum (MPEG), Belem, Para (PA); Aquatic Mammals Laboratory (LMA) of the Department of Ecology and Zoology, Federal University of Santa Catarina (UFSC), Florianopolis, Santa Catarina (SC); as well as the Osteological Archive of the Association of Research and Preservation of Aquatic Ecosystems (AQUASIS), Caucaia, Ceara (CE) (Tables 1-4). The INPA collection contains riverine specimens (S. fluviatilis) from the Amazonas State (AM), marine specimens from the coast of the Amapa (AP) and estuarine specimens (S. guianensis) from Para State (PA). The other collections only possess marine specimens from their respective localities. Forty-four specimens of S. fluviatilis and 105 specimens of S. guianensis were analyzed (AP = 24; PA = 02; CE = 41; SC = 38). The marine specimens were divided into 3 large areas: NOR (including specimens from AP and PA), for the specimens from the coast of Amapa and Para States, CE for the specimens off the Ceara coast and SC for specimens from the Santa Catarina coast.

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The skulls were compared using non-metric characters, in accordance with Perrin et al. (1982) and two newly proposed characters (Table 5; Figures 1-4). The cervical vertebrae were analyzed according to the presence or absence of cervical ribs.

In order to observe ontogenetic variation, the characters were evaluated by age classes (calf, juvenile, immature and adult) (adapted from Dawbin et al., 1970). Variations between the sexes were not analysed in this study due to the small sample size.

The terminology used for skeletal bones followed Flower (1885), Kraglievich (1937), Lessertieur and Saban (1967), Rommel (1990) and Simoes-Lopes (2006).

3. Results

Of the 22 non-metric characters analysed, only six were informative for the distinction between the two species.

3.1. Fenestrae

A high frequency of fenestrae in the occipital region was observed, near the foramen magnum in S. fluviatilis (66%; n = 44). In S. guianensis the percentage of occurrence of fenestrae varied between 31% (specimens from NOR, n = 26), 10 % (CE, n = 41) and 13% (SC, n = 39).

The number of fenestrae near the condyle was also larger in the riverine species, varying from one to four per individual. In both species, these structures were found in all age classes.

In the marine species, the specimens from CE and NOR exhibited one to three fenestrae, while those from SC exhibited only one to two. Fenestrae can occur only on one side (more common in the marine species) or on both sides of the occipital condyle (more common in the riverine species). In newborn and young specimens, other openings in the occipital region (located above the fenestrae) were observed, corresponding to the fontanelles, formed by the union of the exoccipital, parietal and supraoccipital bones (Figure 5).

[FIGURE 4 OMITTED]

In the region of occipital protuberance, in general, the occurrence of fenestrae was less frequent: 4.5% in S. fluviatilis (n = 44), 10% for S. guianensis of CE (n = 41), 5% for specimens from SC (n = 38) and no occurrence for marine specimens from NOR (n = 26). In some specimens of the two species, small fenestrae of irregular contour in the basioccipital were observed. In the marine species, such fenestrae occurred in 2% (n = 41) and 8% (n = 39) of the specimens from CE and SC, respectively. In the riverine species, these fenestrae occurred in 9% (n = 43) of the specimens. These openings were not observed in the marine specimens from NOR.

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3.2. Vomer

There was a prevalence of one form of vomer for the marine species, and another form for the riverine species (Figure 6). The wide form (wider in the posterior region) was more frequent in the riverine species, occurring in 57% (n = 37) of specimens, followed by the intermediate form (32%) and the narrow form (11%) (Figure 7). In the marine species, the narrow form was most frequent, occurring in 76% (n = 21) of the specimens from NOR and in 66% (n = 38) of the specimens from CE. The intermediate form of the vomer occurred in 9.5% (n = 21) of the specimens from NOR and in 31.5% (n = 38) of the specimens from CE. This characteristic was added later to the analysis, thus the specimens from SC were not included in the analyses. This characteristic seems to be related with individual variation and not with development.

3.3. Pterygoids

[FIGURE 8 OMITTED]

The contact, anterior and posterior, between pterygoids exhibited no variation, being separate (gap >1 mm) in 100% of specimens of both species (except for INPA specimen 130 from AP, whose pterygoides had medial contact). In riverine species it was observed that generally there was a greater distance between pterygoids in the posterior portion, forming an inverted "v". Young individuals of marine species seems to present this same greater distance in the posterior portion. This could indicate neoteny in the riverine species, but in order to be able to interpret this variation a more thorough morphometric study is needed.

3.4. Anterior lacerate foramen

The predominant form of anterior lacerate foramen was distinct in the two species (Figures 8 and 9). In S. fluviatilis, the majority of specimens (88%, n = 43) exhibited open/elongated anterior lacerate foramen. In S. guianensis, the majority of the specimens analysed exhibited foramen divided by a projection in the form of a spine: 72% (NOR, n = 25), 77.5% (CE, n = 40) and 98%, (SC, n = 38). This spine projection, which rarely develops in adults of the riverine species, seems to be associated with ontogenetic development in the marine species, leading to the assumption that it is related to neoteny. A more detailed study with a larger number of young and juveniles of both species could provide an answer to this question. In the three marine samples analysed, it was observed that some individual adults exhibited a formation of fusion points between the projection and one side of the lacerate foramen.

3.5. Hypoglossal foramen

The location of hypoglossal foramen next to the jugular notch was considerably higher in S. guianensis: 88% (NOR, n = 25), 95% (CE, n = 41) and 98% (SC, n = 39). In this species, this foramen is generally visible in the ventral view, externally displaced to the jugular notch. Conversely, in the riverine species, the majority of specimens (87%, n = 45) exhibited this foramen internally displaced to the jugular notch, not easily observed in the ventral view (Figures 10 and 11). It is worth noting, however, that variation exists in the proximity of this foramen to the jugular notch in both species, where some individuals exhibit a displaced foramen, being either separated or together with the notch. This characteristic doesn't seem to be related with development.

[FIGURE 9 OMITTED]

[FIGURE 10 OMITTED]

3.6. Cervical vertebrae

In the cervical vertebrae, projections on the seventh cervical vertebrae (Ce7) associated with the transversal canal (= vertebrarterial canals), are called pleuroapophiseal plates or cervical ribs (Figures 12). The occurrence of these structures was higher in S. fluviatilis (87%; n = 31) than in S. guianensis from CE (9%, n = 23) and from SC (19%, n = 32). Furthermore, the size of the ribs is proportionally smaller in the riverine species than in the marine species. In S. guianensis, the cervical ribs were generally observed only on one side (right or left), while in S. fluviatilis they were observed on both sides. The UFSC specimen 1117 exhibited this structure on the on the right side of the third cervical vertebra ([Ce.sub.3]). The cervical ribs were observed in all age classes.

[FIGURE 11 OMITTED]

[FIGURE 12 OMITTED]

4. Discussion

4.1. Fenestrae

The presence of fenestrae commonly observed in the occipital region, near the condyles of Sotalia fluviatilis was also recorded in juveniles and adults of Pontoporia blainvillei (Gervais and d'Orbigny, 1844) (Pinedo,1991). However, in Pontoporia, the number of fenestrae was greater than that observed for the genus Sotalia.

In the genus Sotalia, the occurrence of fenestrae next to protuberances of the occipital region was low compared with the region next to the condyles. In the basioccipital, the presence of fenestrae was less frequent in immature specimens than in mature specimens. In Pontoporia blainvillei and in Stenella the occurrence of this structure was rare and occasional, respectively (Pinedo, 1991; Perrin et al., 1982).

Considering that the fenestrae observed next to the condyles in S. fluviatilis do not have the same origin as the fontanelles present in newborn individuals, given their different location, the origin and function of these fenestrae are not clear.

4.2. Vomer

The cranial floor is not generally included in morphologic studies and revealed interesting results. SimoesLopes (2006), analysing specimens of S. guianensis in the southern region, observed that the laminar posterior process of the vomer is narrower than the lamelar pterygoid processes.

In the same study, the author found the converse in S. fluviatilis--where the vomer is broader and the lamelar pterygoid processes narrower. In the present work we verified that this characteristic described by Simoes-Lopes (2006) was present in the majority of the marine specimens analysed. However, in the samples from CE and AP, we observed that some specimens also possessed a broad vomer, similar to the riverine species, herein called the "wide form". Apparently, this characteristic can be used to distinguish the two species, but it is important to note that a small percentage of marine specimens possess a broad vomer just as some riverine specimens possess a narrow vomer. Thus, the use of this characteristic should be considered in combination to others when separating the species.

In relation to the posterior alignment of the vomer, the arrangement anterior to the lamelars pterygoid processes was observed in 100% of the cases for the marine species. In the riverine species (n = 39), 18% were observed with the posterior edge of the vomer aligned with the pterygoids, while in another 18% the posterior edge of the vomer extended beyond the pterygoides. Dawbin et al. (1970) attribute the alignment of the vomer in relation to the posterior pterygoid processes to age. For these authors, in sub-adults Peponocephala electra (Gray, 1846) the vomer extends to the level of the sutures between the pterygoides and basioccipital and in adults, the vomer extends beyond the adjacent pterygoides. This pattern was not observed in the current study, since all adults of S. guianensis were observed with the posterior suture of the vomer anterior to the pterygoides. Moreover, the variation observed in the riverine species does not appear to be related to ontogenetic development, but rather to individual variation.

4.3. Pterygoides

The pterygoides were found to be medially separated by a projection in the tip of the palatines in all specimens, corroborating the data found in the literature (van Beneden, 1875; Flower, 1885; Miranda-Ribeiro, 1936, da Silva and Best, 1994; 1996; Avila et al., 2002; SimoesLopes, 2006). The variation in the form of the posterior projection of the left pterygoide was very subtle between the two species.

4.4. Anterior lacerate foramen

The anterior lacerate foramen is formed by two foramens (the optic foramen and the orbitorotundum foramen). These two structures are divided by a "wall" (Yamagiwa, et al., 1999) here called a spike-shaped projection. In S. guianensis, the majority of the adult specimens (between 72 and 98%) exhibited this projection between the optic and the orbitorotundum foramen. On the other hand, the narrow form was only observed in adults, suggesting that with time, this spiny projection fused with one side of the lacerated foramen (as observed in some marine specimens). In S. fluviatilis, in contrast, the absence of this projection was more common (88%), and could indicate neoteny.

4.5. Hypoglossal foramen

The location of the hypoglossal foramen varied between the two species. In S. guianensis the hypoglossal foramen generally meets between the crest of the basioccipital and the paraoccipital process, more precisely in the jugular notch as it occurs in other species of marine Delphinidae, for example, Grampus griseus (Cuvier, 1812) (Yamagiwa et al., 1999) and Tursiops truncatus (Montagu, 1821) (Rommel, 1990). In contrast, the hypoglossal foramen in S. fluviatilis, in the majority of cases, was found to be internally displaced.

4.6. Cervical vertebrae

The occurrence of cervical ribs was higher (87%) in the riverine species. The presence of pleuroapophiseal plates was initially suggested for some groups of mammals, especially monotremes and marsupials (Lessertisseur and Saban, 1967). Unilateral or bilateral processes in the cervical vertebrae are common in some groups of mammals (including Homo), and the costal rudiments are associated with the vertebral or vertebrarterial foramens (Lessertisseur and Saban, 1967). These authors also mention their presence in marine mammals as Orcinus orca (Linnaeus, 1758), Tursiops truncatus and Balaenoptera sp. Such processes have been considered serially homologous to the cervical ribs, also appearing in the literature as costal plates or pleuroapophiseal plates (Flower and Lyddeker, 1891). The presence of cervical ribs is an intriguing characteristic in comparative anatomy, as these structures are typically observed in reptiles (Paula Couto, 1979; Ferigolo, 1987). In S. guianensis, these structures have already been reported in about 22.5% (n = 31) of the specimens of the southern region (Fettuccia and Simoes-Lopes, 2004). In this work, considering a larger sample, the observed frequency of cervical ribs in the specimens from SC was 19% (n = 33), and of 9% (n = 23) from CE. Cervical ribs in mammals are examples of atavism (reappearance of an extinct character, common to ancestral lineages that rarely occur in current populations). Other cases of atavism are described in the literature as the occurrence of vestigial posterior members in whales and extra-numeric teeth in bats and sea lions (Bejder and Hall, 2002; Rui and Drehmer, 2004 and Drehmer et al., 2004). According to Hall (1984), there are four basic criteria for the recognition of an atavism: 1) persistence of the characteristic in adult life; 2) absence of this characteristic in the parents or recent ancestors; 3) occurrence in one or a few individuals within a population; and 4) similarity or identity with the same character exhibited by all the members of the ancestral population. Moreover, if the incidence of the character is still relatively high in a population, it is considered a polymorphism (Hall, 1984). Thus, considering the high occurrence of cervical ribs in specimens of the riverine species, these structures do not appear to be atavistic, suggesting the need for a more detailed study with a more representative sample number for a more consistent conclusion.

Acknowledgements--The authors would like to thank Angel Enzo Crovetto, Cesar Drehmer, Fernando Rosas, Lena Geise and two anonymous referees for their helpful suggestions on improving the manuscript. We would also like to thank Nina Best for the English review. Special thanks to the Museu Paraense Emilio Goeldi (MPEG) and Associacao de Pesquisa e Preservacao de Ecossistemas Aquaticos (AQUASIS). This work was supported by grants from CNPq and IEB.

Received December 7, 2007--Accepted August 27, 2008--Distributed August 31, 2009

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Fettuccia, DC. (a)* da Silva, VMF. (a) and Simoes-Lopes, PC. (b)

(a) Laboratorio de Mamiferos Aquaticos--INPA, Av. Andre Araujo, 2936, Aleixo, CEP 69060-001, Manaus, AM, Brazil

(b) Laboratorio de Mamiferos Aquaticos--LAMAQ, Departamento de Ecologia e Zoologia, CCB, Universidade Federal de Santa Catarina--UFSC, CP 5102, CEP 88040-970, Florianopolis, SC, Brazil

* e-mail: fettuccia@hotmail.com
Table 1. List of Sotalia fluviatilis analysed from the northern region
(Amazon State, Brazil), deposited at INPA's mammals collection.
F - female, M - male, I - indeterminate gender. N = 44.

Collection
number       Sex   Age class   Locality

INPA 005     I     adult       Japura River
INPA 007     I     adult       Tefe Lake
INPA 008     I     adult       Tefe Lake
INPA 009     M     juvenile    Negro River
INPA 015     F     calf        Japura River
INPA 016     I     adult       Japura River
INPA 017     M     adult       Japura River
INPA 018     I     calf        Japura River
INPA 020     I     adult       Japura River
INPA 024     I     adult       Japura River
INPA 026     M     juvenile    Purus River
INPA 029     F     juvenile    Tefe Lake
INPA 038     F     calf        Japura River
INPA 039     M     immature    Japura River
INPA 040     F     adult       Amana Lake
INPA 041     M     adult       Negro River/Anavilhanas
INPA 043     M     juvenile    Japura River
INPA 047     M     adult       Jurua River
INPA 050     F     immature    Amana Lake
INPA 051     M     calf        Amazonas River
INPA 052     M     adult       Amazonas River
INPA 053     F     adult       Amazonas River
INPA 054     M     calf        Amazonas River
INPA 055     I     adult       Amazonas River
INPA 056     F     adult       Amazonas River
INPA 057     F     adult       Marchantaria, Solimoes River
INPA 059     M     juvenile    Marchantaria, Solimoes River
INPA 060     M     juvenile    Tefe Lake
INPA 062     F     adult       Japura River
INPA 065     M     calf        Japura River
INPA 067     I     adult       Negro River/
INPA 069     F     adult       Anavilhanas
INPA 071     F     adult       Japura River
INPA 072     I     adult       Para River
INPA 073     F     adult       Purus River
INPA 074     M     adult       Purus River
INPA 080     M     calf        Catalao, Negro River
INPA 081     M     juvenile    Cabaliana Lake, Manacapuru
INPA 082     F     calf        Tapajos River
INPA 093     M     adult       Tocantis River/Tucurui
INPA 097     F     juvenile    Negro River
INPA 113     M     adult       Solimoes River
INPA 149     I     adult       Coari Grande River
INPA 151     I     adult       Coari Grande River

Table 2. List of Sotalia guianensis analyzed from northern region
(Amapa and Para States, Brazil), deposited at INPA and MPEG mammals
collections, respectively. F - female, M - male, I - indefinite
gender. N = 26.

Collection
number       Sex   Age class   Locality

INPA 120     M     juvenile    Amazonas Estuary
INPA 121     M     juvenile    Amazonas Estuary
INPA 122     M     juvenile    Amazonas Estuary
INPA 123     M     adult       North of Amapa
INPA 124     F     juvenile    North of Amapa
INPA 125     F     juvenile    Amazonas Estuary
INPA 126     M     juvenile    North of Amapa
INPA 127     M     calf        North of Amapa
INPA 128     M     calf        North of Amapa
INPA 129     M     adult       North of Amapa
INPA 130     F     juvenile    North of Amapa
INPA 131     F     calf        Amazonas Estuary
INPA 132     F     calf        Amazonas Estuary
INPA 133     M     juvenile    North of Amapa
INPA 134     F     adult       North of Amapa
INPA 135     F     calf        North of Amapa
INPA 136     M     calf        North of Amapa
INPA 137     M     calf        North of Amapa
INPA 138     F     juvenile    North of Amapa
INPA 139     F     juvenile    North of Amapa
INPA 140     M     juvenile    North of Amapa
INPA 141     F     adult       North of Amapa
INPA 142     F     adult       North of Amapa
INPA 143     F     adult       North of Amapa
MPEG 24548   I     adult       Marajo Island
MPEG 10945   F     juvenile    Marajo Island

Table 3. List of Sotalia guianensis analysed from the
Northeast region (Ceara state, Brazil), deposited at AQUASIS's
collection. F - female, M - male, I - indeterminate gender. N = 41.

Collection
number       Sex   Age class   Locality

Aq 002       M     adult       Caucaia
Aq 004       I     juvenile    Fortaleza
Aq 012       I     adult       Fortaleza
Aq 013       M     adult       Fortaleza
Aq 023       M     adult       Caucaia
Aq 026       I     adult       Caucaia
Aq 036       F     adult       Fortaleza
Aq 038       M     adult       Caucaia
Aq 039       I     adult       Sao G. Amarante
Aq 040       I     calf        Sao G. Amarante
Aq 041       I     immature    Fortaleza
Aq 042       M     adult       Fortaleza
Aq 058       F     adult       Fortaleza
Aq 071       I     adult       Cascavel
Aq 084       M     adult       Fortaleza
Aq 132       M     juvenile    Sao G. Amarante
Aq 134       M     adult       Fortaleza
Aq 139       I     adult       Itapipoca
Aq 159       I     adult       Fortaleza
Aq 184       F     adult       Fortaleza
Aq 196       I     immature    Sao G. Amarante
Aq 210       F     adult       Paracuru
Aq 212       F     adult       Fortaleza
Aq 213       M     calf        Fortaleza
Aq 214       F     juvenile    Caucaia
Aq 215       I     adult       Sao G. Amarante
Aq 218       M     juvenile    Sao G. Amarante
Aq 222       F     adult       Fortaleza
Aq 231       M     adult       Caucaia
Aq 232       M     adult       Fortaleza
Aq 234       M     adult       Caucaia
Aq 236       I     adult       Sao G. Amarante
Aq 239       M     adult       Fortaleza
Aq 240       I     immature    Paraipaba
Aq 241       I     adult       Caucaia
Aq 247       F     adult       Fortaleza
Aq 250       M     calf        Paraipaba
Aq 251       I     adult       Traire
Aq 253       M     adult       Fortaleza
Aq 259       M     adult       Fortaleza
Aq 262       I     adult       Bitupita
-            -     -           -

Table 4. List of Sotalia guianensis analysed from the Southern
region (Santa Catarina state, Brazil), deposited at LAMAq's
collection (UFSC). F - female, M - male, I - indeterminate gender.
N = 38.

Collection
number       Sex   Age class   Locality

UFSC1010     I     juvenile    Daniela Beach
UFSC1073     I     adult       Biguacu
UFSC1079     F     adult       Beira Mar Norte
UFSC1082     I     adult       Beira Mar Norte
UFSC1083     M     adult       Beira Mar Norte
UFSC1104     F     immature    Beira Mar Norte
UFSC1108     M     adult       Beira Mar Norte
UFSC1117     I     adult       Biguacu
UFSC1130     F     adult       G. Celso Ramos
UFSC1174     M     calf        Sambaqui
UFSC1175     M     adult       Sao F. do Sul
UFSC1176     I     adult       Costeira
UFSC1178     M     juvenile    Sambaqui
UFSC1179     M     juvenile    Beira Mar Norte
UFSC1180     F     adult       Cacupe
UFSC1203     F     adult       Anhatomirim
UFSC1208     F     adult       Estreito
UFSC1218     F     adult       Curtume Beach
UFSC1219     F     adult       Costeira
UFSC1222     M     immature    Estreito
UFSC1223     M     calf        Anhatomirim Island
UFSC1226     M     adult       G. Celso Ramos
UFSC1236     F     calf        Sambaqui
UFSC1245     I     juvenile    Sao F. do Sul
UFSC1247     I     adult       Cacupe
UFSC1253     M     juvenile    Beira Mar Norte
UFSC1266     M     immature    Biguacu
UFSC1268     F     adult       Biguacu
UFSC1289     F     adult       G. Celso Ramos
UFSC1291     M     adult       G. Celso Ramos
UFSC1296     M     juvenile    Anhatomirim
UFSC1297     M     adult       G. Celso Ramos
UFSC1302     I     adult       Itapoa
UFSC1307     M     juvenile    Daniela Beach
UFSC1311     I     immature    Sao F. do Sul
UFSC1312     M     adult       Estreito
UFSC1321     F     adult       Itaguacu Beach
UFSC1327     M     calf        Beira Mar Norte

Table 5. List of non-metric characters analysed in skulls and
cervical vertebrae from specimens of the genus Sotalia. Adapted
from Perrin et al. (1982) and two new proposed characters (4a e

4g). NI: not illustrated.

Figure character and character condition

1 a. Asymmetry of position of the two anterior most large maxillary
foramina: 1- symmetrical; 2- left foramen more anteriorly placed;
right foramen more anterior.

b. Number of small foramina in the maxillary anterior to the
anterior-most of the three large foramina.

c. Number of foramina in the maxillary behind a line at the level
of the anterior edge of the external nares and perpendicular to the
long axis of the skull.

d. Contact between maxillary and occipital, at point where
occipital crest intersects margin of temporal fossa: 1- contact (or
space of <1 mm); 2- no contact.

e. Contact between premaxillary and nasal, on right side: 1-
contact (or space of <1 mm); 2- no contact.

f. Asymmetry of position of the two premaxillary foramina: 1-
symmetrical; 2- left foramen more anteriorly placed; right foramen
more anterior

g. Development of dorsal mesethmoid spine at the anterior margin of
external nares, between angles of premaxillaries: 1- elevation of
the ossified portion of the mesethmoid to, or near to the level of
the dorsal surfaces of the premaxillaries; 2- no such elevation.

2 Composition of the anteorbital process, in lateral view, of the
left side: 1- formed by lacrimal; 2- formed by lacrimal and
frontal; 3- formed lacrimal and maxillary.

3 a. Medial occipital ridge, projecting above level of the
occipital swellings at mid-height: 1- present; 2- absent, or not
projecting above swellings.

b. Accessory foramen above foramen magnum: 1- present; 2- absent.

c. Clear notch in upper margin of foramen magnum: 1- present; 2-
absent.

d. Number of fenestrations in occipital, near foramen magnum and in
exoccipital region.

e. Number of fenestrations in region of occipital swellings.

4 a. Shape of the vomer among posterior process of the pterygoids:
1- wide; 2- intermediate; 3- narrow.

b. Anterior contact between pterygoid hamuli: 1- open (gap > 1 mm);
2- closed.

b. Posterior contact between pterygoid hamuli: 1- open (gap > 1
mm); 2- closed.

d. Shape of posterior projection of left pterygoid hamulus: 1-
longer than wide (y > x); 2- wider than long, or equal (x > y).

e- Vomer's posterior alignment in relation to pterygoids's lamellar
process: 1- anterior; 2- aligned; 3- posterior.

f- Number of fenestrations in region of basoccipital.

g- Shape of the anterior lacerate foramen (right): 1- open; 2- with
projection spine form; 3- narrow.

h- Visibility, in ventro-occipital view of mesially directed
hypogossal foramen between basoccipital and exoccipital process
(jugular notch): 1- visible; 2- not visible.

NI Cervical rib: 1- present; 2- absent.
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Author:Fettuccia, D.C.; da Silva, V.M.F.; Simoes-Lopes, P.C.
Publication:Brazilian Journal of Biology
Article Type:Report
Date:Aug 1, 2009
Words:5086
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