New material and phylogenetic position of the basal iguanodont dinosaur Delapparentia turolensis from the Barremian (Early Cretaceous) of Spain.
Many Lower Cretaceous localities from the Iberian Peninsula have yielded iguanodont remains, some of which belong to one of several European taxa such as Mantellisaurus (Sanz et al., 1984; Llandres Serrano et al., 2013) or Iguanodon (Gasulla et al., 2014), others of which are only described in Iberia, such as Delapparentia and Proa (Ruiz-Omenaca, 2011; McDonald et al., 2012b), while others belong to as yet undescribed taxa (Fuentes Vidarte et al., 2005; Gasca et al., 2009; Pereda-Suberbiola et al., 2011). Taking into account only the confirmed taxa, the Iberian fauna of basal iguanodonts is distributed over the course of the Early Cretaceous as follows: Delapparentia turolensis in the Barremian (RuizOmenaca, 2011), Iguanodon bernissartensis in the Aptian (Gasulla et al., 2014), and Proa valdearinnoensis in the Albian (McDonald et al., 2012b). This limited faunal list contrasts with the diversity of iguanodonts in the faunas of the Lower Cretaceous of Europe (Table 1), where the coexistence of at least two taxa has been registered for each time interval (Norman, 2010; 2011a).
However, it is possible that the Early Cretaceous Iberian iguanodontian faunas are in fact more diverse than can be known for certain at present. This is suggested by the presence of forms related to Mantellisaurus and Owenodon in the Barremian and Aptian of Spain (Ruiz-Omenaca, 2006; Galton, 2012; Llandres Serrano et al., 2013; Gasulla et al., 2014), as well as the coexistence of potentially distinct taxa, such as a tall-spined iguanodontian from Burgos (Pereda-Suberbiola et al., 2011). An additional line of evidence is the differentiation of dental morphotypes recorded in some Iberian fossil localities (Gasca et al., 2008; Canudo et al., 2010; Gasca et al., 2014).
The Barremian iguanodont record from the Iberian Range is abundant but fragmentary and undiagnostic in most cases. Delapparentia turolensis is the only taxon described in this interval of time. It is described on the basis of a partial postcranial skeleton recovered from the La Maca-3 locality, which is located on a small hill two kilometres east of the village of Galve (Fig. 1). Early Cretaceous outcrops of Galve are located within the Galve Sub-basin, in the Maestrazgo Basin (Fig. 1). The fossiliferous levels comprise lutites that represent floodplain deposits located in the middle part of the Camarillas Formation (Fig. 1). This formation is a predominantly fluvial unit from the Wealden facies (Diaz Molina and Yebenes, 1987) and is Barremian (Early Cretaceous) in age (Canudo et al., 2012).
In addition to Delapparentia, the dinosaur record from the Camarillas Formation in Galve is composed of the basal ornithopod Gideonmantellia amosanjuanae (Ruiz-Omenaca et al., 2012), represented by an isolated skeleton, as well as other taxa represented by isolated remains identified as Stegosauria indet., Ornithopoda indet., Iguanodontoidea indet., Sauropoda indet., Euhelopodidae indet., Allosauroidea? indet., and several Maniraptoriformes (Sanz et al., 1987; RuizOmenaca et al., 2004; Ruiz-Omenaca, 2011).
Fossil remains of Delapparentia were discovered and collected in the 1950s by the local amateur Jose Maria Herrero in Galve (Teruel, Spain) and were initially described by Lapparent (1960), who assigned them to Iguanodon bernissartensis. The holotype (Museo de Teruel, MPT/I.G.) was the only record of this taxon until recently (Gasca et al., 2014). Since its discovery, several fragmentary remains have been recovered during subsequent fieldwork at the outcrop and on the dump of the original excavation. One of these remains, together with previously unidentifiable fragments, has allowed us to reconstruct most of the neural arch of the axis. The proximal part of the left scapula has also recently been recovered, representing the first known remnant from the scapular girdle of Delapparentia. Ruiz-Omenaca (2011) erected Delapparentia and identified it as a non-hadrosaurid iguanodontoid, but no phylogenetic analysis was presented. Delapparentia was included in a data matrix in subsequent studies of basal iguanodont phylogeny, but its phylogenetic position was not analysed (McDonald, 2012a; McDonald et al., 2012b).
The aim of this paper is to describe new, unpublished material belonging to the holotype specimen of Delapparentia turolensis, as well as reviewing the diagnosis after first-hand examinations of the previously published material and analysing the phylogenetic position of this taxon for the first time.
Institutional abbreviation: MPT: Museo de Teruel, Teruel, Spain.
2. Systematic Palaeontology
Dinosauria Owen, 1842
Ornithischia Seeley, 1887
Ornithopoda Marsh, 1881
Iguanodontia Dollo, 1888
Styracosterna Sereno, 1986
Delapparentia Ruiz-Omenaca, 2011
Delapparentia turolensis Ruiz-Omenaca, 2011
Holotype: MPT/I.G., a partial postcranial skeleton that comprises the neural arch of the axis and another four cervical vertebrae, one centrum and some fragments of neural arches of dorsal vertebrae, three vertebral centra and some fragments of neural spines of sacral vertebrae, nine anterior caudal vertebrae, cervical and dorsal rib fragments, five haemal arches, ossified tendon fragments, a proximal fragment of the right scapula and the incomplete left pelvic girdle represented by the anterior and dorsal part of the ilium, prepubis and a proximal fragment of the ischium (Figs. 2, 3, 5, 6).
Occurrence: La Maca-3 locality, corresponding to the Barremian (Lower Cretaceous) Camarillas Formation, near the village of Galve, Teruel province, Spain (Fig. 1).
Emended diagnosis: styracosternan ornithopod characterized by a single autapomorphy: axis with neural spine tall (i.e. the height from the base of the postzygapophysis is greater than half the length of the neural arch). Furthermore, Delapparentia turolensis can be distinguished from other basal iguanodonts because it possesses the following unique combination of characters: the lateral surface of the preacetabular process twists around its long axis towards its anterior end so that it comes to face almost dorsally; the rim of the sacrodorsal rib facet is visible, in lateral view, in the preacetabular notch; in profile, the dorsal edge of the ilium is practically straight between the anterior end of the preacetabular process and the part dorsal to the ischial peduncle; the anterior caudal vertebrae have dorsoventrally expanded (i.e. higher than wide) centra; the neural spines of the caudal vertebrae are elongated, posterodorsally inclined and transversely thickened; the prepubic process is expanded with dorsal and ventral edges that diverge towards its anterior end, the ventral edge being more concave than the dorsal in profile.
Comments: In the original diagnosis, Ruiz-Omenaca (2011) provided the following autapomorphies for Delapparentia turolensis: 1) posterior dorsal ribs with long, parallel and unfused capitulum and tuberculum, 2) ossified sternal ribs, and 3) horizontal, twisted and lateromedially expanded preacetabular process of ilium (convergent in Zalmoxes), as well as the presence of anterior dorsal ribs with a pneumatic foramen and an ischium that is large in relation to the ilium. None of these has been retained in our proposal, at least in its original sense. The posterior dorsal ribs with long, parallel and unfused capitulum and tuberculum (1) were misinterpreted. These rib fragments (see Fig. 4H, I in Ruiz-Omenaca, 2011) are actually posterior dorsal ribs with the tuberculum fused with the diapophysis of the corresponding dorsal vertebra (Fig. 2g). This could indicate a mature age - even an old state - in this individual and is coherent with the ossification observed between some caudal centra of the individual (Fig. 2a), which was previously reported and discussed by Lapparent (1960) and Ruiz-Omenaca (2011). Partial ossification of sternal rib segments (2) has been reported in other iguanodont taxa such as Mantellisaurus and Iguanodon and other basal ornithopods such as Dryosaurus, Camptosaurus or Zalmoxes (Weishampel et al., 2003: character 11). As for the ilium, the horizontal, twisted and lateromedially expanded preacetabular process of the ilium (convergent in Zalmoxes, 3) has been modified because, despite being lateromedially expanded, the preacetabular process of Delapparentia differs with respect to the twisted dorsal margin of Zalmoxes (Weishampel et al., 2003: fig. 22; Godefroit et al., 2009: fig. 18). The preacetabular process of Zalmoxes twists along its length such that the dorsal surface of the ilium becomes the lateral surface of the anterior end of the process, whereas in Delapparentia the lateral edge of the process comes from the lateroventral edge ending dorsal to the pubic peduncle, this morphology being closer to the typical horizontal boot of other iguanodonts (McDonald et al., 2012a) and similar to the morphology that Norman (2011a) describes as an autapomorphic character in Barilium. As regards the additional characters provided in the original diagnosis, the pneumatic foramen previously identified in the anterior dorsal ribs (Ruiz-Omenaca, 2011: fig. 4G) is a slight pit with a bulge that seems rather to be a structure like a muscle attachment (Fig. 2f). Finally, an ischium that is large in size in relation to the ilium is ambiguous in nature as a character and in any case invalid because the ilium is actually less complete than Ruiz-Omenaca (2011) considered (see description below).
Deseription and eomparison
In this chapter only the new material (axis and scapula) is described in detail, as well as the older material that is relevant for the diagnosis. For a complete description of all postcranial remains of Delapparentia turolensis see RuizOmenaca (2011).
The fossil remains show good preservation, with no evidence of significant biostratinomic alteration. The post-burial distortion is not significant for the systematics. Most of the information loss in the holotype bones is a result of the inadequate collection of this material in the 1950s.
Only the neural arch is known, with the regions of the neural spine and right postzygapophyseal complete, while no remains have been recovered below the roof of the neural channel, the prezygapophyses and the transverse processes being absent (Fig. 3).
The axial neural spine is lateromedially compressed and dorsally convex in lateral view (Fig. 3), forming a large blade-like structure similar to those of basal iguanodonts such as Iguanodon (Norman, 1980: Fig. 24), and quite dissimilar from the sloping, dorsally concave axial neural spines of more basal iguanodontians such as Tenontosaurus tilletti (Winkler et al., 1997) or Camptosaurus dispar (Gilmore, 1909). The neural spine is exceptionally tall. Delapparentia is the only taxon among the iguanodonts and basal ornithopods so that the height of the axial neural spine from the base of the postzygapophysis is clearly greater than half the length of the neural arch (Fig. 4). This relationship between height and length expressed as a percentage is 59% in Delapparentia, which contrasts with the lower values in other ankylopollexians (Fig. 4), such as 48% in Camptosaurus dispar (Gilmore, 1909), 46% in Iguanodon (Norman, 1980), 45% in Ouranosaurus (Taquet, 1976), and 43% in Tanius (Wiman, 1929), and with much lower values such as 37% in Mantellisaurus (Norman, 1986), 28% inMantellisaurus sp. (Norman, 1987), and 35% in Bactrosaurus (Godefroit et al., 1998).
The anterior end is hook-shaped, as in other basal iguanodonts such as Iguanodon (Norman, 1980). The lateral surfaces are slightly concave, with the presence of at least two tiny foramina visible in the left side (Fig. 3d). The apex of the neural spine is strongly convex and posteriorly placed as in Iguanodon (Norman, 1980), but unlike other basal iguanodonts such as Iguanacolossus, Mantellisaurus and Ouranosaurus and hadrosauroids such as Bactrosaurus and Tanius, where the apex of the neural spine is gently convex and there is a slight embayment between the apex and the posterior edge.
Posteriorly, the neural spine bifurcates in dorsal view to form two divergent, posterolaterally directed buttresses. Each buttress bears a posteriorly directed, blunt bulge (i.e. epipophysis) in the dorsal part, a small, posterolaterally directed, blunt bulge in the middle part, and ends in a large, lateroventrally oriented and elliptical postzygapophyseal facet. The epipophyses are positioned ventral to the dorsal margin of the neural spine, as in Iguanodon (Norman, 1980) and Jinzhousaurus (Wang et al., 2011), and unlike Mantellisaurus (Norman, 1986) and Ouranosaurus (Taquet, 1976), where they are positioned approximately at the same level. A similar blunt accessory process between the epipophysis and postzygapophysis is also present in Iguanodon (Norman, 1980) and Mantellisaurus (Norman, 1986, 1987), and poorly defined in Ouranosaurus (Taquet, 1976), whereas it is absent in Camptosaurus (Gilmore, 1909), Jinzhousaurus (Wang et al., 2011), Bactrosaurus (Godefroit et al., 1998) and Tanius (Wiman, 1929).
Only a proximal portion of the right scapula is preserved (Fig. 5). The anterior margin is lateromedially thickened along the articular surface for the coracoid. In profile, the edge between the glenoid - in the anteroventral margin - and the articular surface for the coracoid is pronounced, as in cf. Barilium (Norman, 2011a: Fig. 21), and unlike in other iguanodonts (e.g. Mantellisaurus, McDonald, 2012b: fig. 4; Eolambia, McDonald 2012a: fig. 27). The acromion process is dorsally directed, as in other basal iguanodonts (e.g. Eolambia, McDonald et al., 2012a: fig. 27), and unlike in hadrosaurids (McDonald, 2012a: character 102). In lateral view, the shape of the acromion process is convex in general terms (Fig. 5a), although it is difficult to discern whether it is more similar to the subtriangular shape of Barilium or to the convexity usual in other iguanodonts (McDonald, 2012a: character 101). This difficulty is a consequence of the incompleteness of the process in its anterodorsal margin and the presence of a slight distortion.
The completeness of the left ilium was originally overestimated by Ruiz-Omenaca (2011). In fact, it is preserved more fragmentarily, with the ventral half and most of the preacetabular process lost due to their breakage during excavation. This reinterpretation is based on the presence of facets for the attachment of the sacral yoke in the ventralmost pre served part (Fig. 6). This implies that the entire ilium would be larger than expected. The ilium, as preserved, is 780 mm long and 170 mm deep. Using the ilium of Barilium (Norman, 2010: fig. 3) as a point of comparison to reconstruct the entire ilium of Delapparentia, it would have an approximate length of 1120 mm and a depth of 370 mm. The ilium of Delapparentia is bigger than the Barilium holotype and comes close in size to the biggest known individual of Iguanodon (NHMUK R2502, Norman, 2011b: fig. 27.50). The large size of the Delapparentia holotype may be due to the senile state of the individual, which is also suggested by the fusion of certain axial elements (dorsal ribs and neural arches, pairs of caudal centra) and the ossification of the sternal ribs.
The preacetabular process (Fig. 6) of the ilium projects anteriorly and terminates in a flattened, horizontal boot. The lateral surface of the preacetabular process twists around its long axis towards its anterior end so that it comes to face almost dorsally as in Barilium (Norman, 2011a) and unlike all other iguanodonts. The maximum lateromedial expansion occurs halfway along and decreases progressively in width towards the anterior end, which is complete and superficially eroded only at the edges of the tip.
In the preacetabular notch, the rim of the sacrodorsal rib facet is visible in lateral view (Fig. 6), which is a synapomor phy only shared with Barilium and the specimen NHMUK R2502 (holotype of Iguanodon seelyi and currently assigned to Iguanodon bernissartensis, Norman, 2011b: fig. 27.50).
In profile, the dorsal edge is nearly straight in the central portion of the body, as well as in the proximal part of the preacetabular process (i.e. dorsal to the preacetabular notch), as in Camptosaurus (McDonald, 2011), Cedrorestes (McDonald et al., 2010b: Fig. 18), Hypselospinus (Norman, 2010) and Eolambia (McDonald et al., 2012a), and unlike in other iguanodonts. The profile of Delapparentia differs slightly from Barilium (Norman, 2011a), with its gently convex dorsal margin, and fromMantellisaurus (Norman, 1986), with its dorsal margin straight in the central portion of the body but convex dorsal to the preacetabular notch, and differs clearly from basal iguanodonts such as Iguanaeolossus (McDonald et al., 2010b), Iguanodon (Norman, 1980) and Ouranosaurus (Taquet, 1976), with a clearly convex dorsal edge, and from hadrosauroids such as Gilmoreosaurus or Corythosaurus (McDonald et al., 2010b: fig. 17), with a marked convexity dorsal to the preacetabular notch. In dorsal view, the dorsal edge of the ilium is rounded dorsal to the pubic peduncle and progressively increases its width caudally to become a rugose, thick, flattened dorsal edge that faces dorsolaterally. This morphology differs clearly from the transversely com pressed dorsal edge of Hypselospinus (Norman, 2010) and is difficult to distinguish from Barilium, whose flat, transversely thick dorsal edge is considered autapomorphic by Norman (2011a). However, the posteriormost part of the dorsal edge preserved in Delapparentia represents a morphology different from the laterally everted rim of iguanodontoids such as Iguanodon (Norman, 1980), Proa (McDonald et al., 2012b) and Mantellisaurus (Norman, 1986).
The lateral surface of the ilium is nearly flat, displaying a slight concavity dorsoventrally. The medial surface is flattened in its dorsal half and limits ventrally with some excavated facets for the attachment of the sacral yoke (Fig. 6). Only the dorsal border of this faceted area is preserved, which corresponds to dorsolateral extensions of the fused upper parts of the sacral ribs and transverse processes of the sacral vertebrae (Norman, 2011a).
Only two fragments of the left pubis are preserved, comprising almost all the prepubic process, the iliac peduncle and acetabulum, whereas the postpubis and ischial peduncle are lost by breakage (Fig. 2d, Ruiz-Omenaca, 2011: fig. 7). The prepubic process is well preserved in its dorsal and ventral edges and only slightly eroded in the anteroventral edge. The two fragments of the pubis do not fit exactly but the bone lost between the anterior end and the proximal part seems to be minimal. The prepubic process is expanded, with a thick, rounded dorsal edge and a thin, sharp ventral margin, which diverge towards its anterior end, as is usual in iguanodontoids (e.g. McDonald et al., 2012a). In profile, the ventral margin is more concave than the dorsal margin, as in Iguanodon (Norman, 1980: fig. 65) and Altirhinus (Norman, 1998: fig. 33), though the opposite is usually the case in basal iguanodonts (e.g. Mantellisaurus holotype, NHMUK R5764; Norman, 2011a: fig. 27.45). In other iguanodonts the dorsal margin is more concave whereas the ventral margin is gently concave or straight (see Paul, 2008: fig. 3C) and even slightly convex as in Eolambia (McDonald et al., 2012a). In spite of the similar outline of the prepubic blade, the anterior end of the prepubis in Delapparentia, with the most anterior point dorsally offset, differs from that of Iguanodon (Norman, 1980) and Altirhinus (Norman, 1998), which is ventrally offset; nonetheless, this difference should be taken with caution due to the above-mentioned slight incompleteness of the anteroventral edge of Delapparentia. The iliac peduncle projects posterodorsally, with a subrectangular articular facet, as is usual in other iguanodonts and different from Proa, which faces dorsally (McDonald et al., 2012b: fig. 31). The pubis of the holotype of Barilium (Norman, 2011a: fig. 9) also differs in the acetabular region because it presents a ridge between the iliac peduncle and the acetabulum, forming a wider angle, whereas the angle is markedly more acute in Delapparentia (Ruiz-Omenaca, 2011: fig. 7). This means that in Delapparentia the ischial peduncle is more prominent and angulated in relation to the acetabular border, whereas in Barilium the ischial peduncle is low and the acetabular border shallow.
3. Phylogenetic analysis
To explore the phylogenetic position of Delapparentia turolensis we incorporated the newly reported skeletal remains in the dataset of McDonald (2012a) and McDonald et al. (2012b). This allowed us to score two new characters (93, 102), one related to the axis and one to the scapula. Further more, we revised character 110, adding a new character state (2) to better describe the morphology of the preacetabular process of the ilium shared by Delapparentia and Barilium dawsoni (see discussion for details). We also rescored two characters in accordance with our reinterpretation of the ilium of Delapparentia (see description): character 112, concerning the morphology of the dorsal margin of the postacetabular process, was changed from state 3 (thickened and laterally-bulging everted rim along dorsal margin) to state 2 (mediolaterally thickened dorsal margin compared to dorsal margin above pubic peduncle). Also, character 114, concerning the orientation of the postacetabular process, was scored as ambiguous (?) due to the lack of most of the postacetabular process. These modifications resulted in Delapparentia being scored for a total of 10 characters (see Appendix 1). Although it is widely known that this dataset usually produces unsatisfactory results, especially concerning the low resolution of the obtained consensus, we have chosen it as it is currently the largest compilation of iguanodonts' osteological information available in the literature. We consider that the dataset can be greatly improved by the progressive addition and recodification of both taxa and characters, and subsequently the resolution of the consensus will be progressively improved in future iterations of the dataset. McDonald (2012a) proposal represents the first modern attempt to put together an inclusive dataset of iguanodonts, and should be consider as a valuable work-in-progress. In that sense, we are aware that some included problematic taxa, such as Kukufeldia and Xuwulong, may need further revision, but without first hand examination of the specimens we choose not to rescore or delete these taxa.
We conducted the analysis under TNT v1.1 (Goloboff et al., 2008) using the settings of the "second run" in McDonald (2012a): all characters were equally weighted; twelve characters (10, 14, 20, 25, 46, 67, 81, 82, 83, 100, 127, and 130) were treated as additive. The resulting dataset was explored with Wagner starting trees (starting seed=1) and 10,000 replicates were used saving 10 trees per replication. This procedure resulted in 17,060 most parsimonious trees (MPTs) of 398 steps, a tree set similar in size to that obtained by McDonald (2012a). The resulting strict consensus is identical to the one obtained by McDonald (2012a), with the inclusion of Delapparentia within the huge polytomy of all taxa more derived than Hypsilophodon.
In order to improve the resolution, we tested different methods. McDonald et al. (2012b) used an Adams consensus tree to obtain a higher resolution. However, Adams consensus trees are widely known to report nodes that are not observed in any of the original MPTs (see for example Bryant, 2003). Due to the huge size of the tree set analysed, the necessary revision of all trees to ensure that no spurious nodes were obtained is difficult, so we consider that this kind of consensus is not ideal for this dataset. Following McDonald et al. (2012b), we calculated all Maximum Agreement Subtrees (MASTs) of the 17,060 MPTs obtained in the analysis us ing PAUP* 4.0b (Swofford, 2003), as this generally resolves MASTs more quickly than TNT. We recovered a total of 288 equivalent MASTs, each including 40 taxa. Most of these MASTs differed in the alternative inclusion of a few taxa, the most relevant to our study being the permutation with Proa and Iguanodon as the basal members of Iguanodontoidea. We chose to figure the MAST which includes the greatest number of taxa that are close to Delapparentia in age or palaeobiogeographical distribution. Again, all these MASTs resulted in the pruning of Delapparentia. To study the approximate phylogenetic affinities of the Iberian taxon we a posteriori pruned in the strict consensus all the taxa not included in the MAST but Delapparentia, with TNT. We also retained in the consensus two taxa that have been previously reported from the Lower Cretaceous of Europe, Hypselospinus and Proa. The resulting consensus subtree is shown in Fig. 7.
Nevertheless, it is noteworthy that more exhaustive searches produced increasingly bigger tree sets -for example, an additional round of TBR (Tree Bisection and Reconection) using the 17,060 trees obtained above may lead to a tree set one order of magnitude bigger-. This problem directly correlates with the huge amount of missing data in the dataset (58% of the character states scored, most of them concentrated in a few poorly represented taxa, as noted by McDonald, 2012a). Exploratory searches of the dataset revealed that this increase in the number of trees obtained does not affect either the topology of the consensus or the size of the MASTs. We have chosen to restrict our comments to the smallest original tree set for comparative purposes and because a deep revision of the dataset and exploratory methodology is out of the scope of this paper, though it could prove an interesting path to follow in future work. To evaluate the support of our results, 1000 bootstrap replications were conducted in TNT, considering only the taxa included in the depicted subtree. Bootstrap values over 50 are shown in Fig. 7.
Delapparentia is recovered in a polytomy with Kukufeldia, Lanzhousaurus, Barilium and the clade equivalent to Iguanodontoidea. Other European iguanodonts from the Early Cretaceous are more derived than Delapparentia. Proa is recovered in a polytomy with Iguanodon bernissartensis and the clade that contains all more derived iguanodonts, including Hypselospinus and Mantellisaurus. Low bootstrap support is recovered for most nodes, with the exception of the clade that includes all iguanodonts more derived than Hypsilophodon, the Zalmoxes + Rhabdodon clade, the clades equivalent to the genus Zalmoxes and Tenontosaurus, and the Corythosaurus + Edmontosaurus clade.
The axis of Delapparentia differs from that of other iguanodonts in presenting a high neural spine measured from the base of the postzygapophysis. This measurement is clearly greater than half the length of the neural arch. The axial neural arch is similar to that of Iguanodon bernissartensis (Norman, 1980) in presenting a dorsally expanded spine, a dorsal edge that is strongly convex, a distally placed apex with an absent posterior concavity, an epipophysis ventral to the apex, and the presence of an accessory bulge on the buttresses between the epipophysis and postzygapophysis. Furthermore, basal iguanodontoids such as Mantellisaurus (Norman, 1986) and Ouranosaurus (Taquet, 1976) differ from Delapparentia and Iguanodon in presenting an axial neural spine that has a gently convex apex placed near the mid-length of the neural arch, a slight concavity posterior to the apex, and an epipophysis placed at the same height as the apex.
The axis of Barilium is unknown; however, Delapparentia can be clearly differentiated from Barilium (Norman, 2011a) in the rest of the axial skeleton. The mid-anterior dorsal vertebrae with a gentle ventral midline keel in Delapparentia are absent in Barilium, the vertebrae having smoothly convex ventral surfaces (Norman, 2011a: fig. 4). The first anterior caudal centrum is higher than wide in Delapparentia, as is common in other basal iguanodonts, whereas in Barilium it is characteristically low and broad (Norman, 2011a: fig. 6). The two taxa also differ in the pubis, in the region of the iliac peduncle (see description and comparison above). Additionally, as well as the Barilium holotype, other material referred to the genus Barilium by Norman (2011a: NHMUK R3788, holotype of Sellacoxa pauli sensu Carpenter and Ishida, 2010) differs from Delapparentia in many pelvic features relating to the ilium, ischium and pubis (see related discussion of NHMUK R3788 below). Even so, the ilia of Delapparentia and Barilium are very similar - except in their slightly different dorsal edge in profile view - and exhibit two characters only shared between them, namely the lateral surface of the preacetabular process facing dorsally towards its anterior end, and the rim of the sacrodorsal rib facet that is visible, in lateral view, in the preacetabular notch. These synapomorphies were previously reported by Norman (2011a) as autapomorphies of Barilium. The similarities in the ilia suggest a close affinity between the English Valanginian Barilium dawsoni and the Spanish Barremian Delapparentia turolensis. The af finity between these European Early Cretaceous taxa, which is also observed in the phylogenetic analysis we performed (Fig. 7), had previously gone unnoticed.
The modification of the matrix of McDonald (2012a) with additional character states and coding changes has contributed to Delapparentia being placed close to Barilium; concretely, in a polytomy with Barilium, Kukufeldia and Lanzhousaurus and outside the clade Iguanodontoidea. The English Valanginian Kukufeldia is known from a dentary (McDonald et al., 2010a) and has been proposed as a junior synonym of Barilium (Norman, 2011a). It lacks overlapping material with Delapparentia, so comparison is impossible. The Asian Early Cretaceous Lanzhousaurus (You et al., 2005) is known from a partial skeleton. As regards the overlapping material, among the most diagnostic bones are the pubes, which differ from Delapparentia in the prepubic profile. The ilium morphology of Delapparentia differs clearly from other iguanodontoids, as is reflected in the data matrix. More precisely, Barilium and Delapparentia share a synapomorphic preacetabular process (McDonald, 2012a: character 110) and lack the laterally everted rim shared by all other basal iguanodontoids, which becomes pendant in derived forms (McDonald, 2012a: character 112).
The ilium of Delapparentia is different from that of Iguanodon. Moreover, the two taxa differ in the last sacral vertebra, which is ventrally grooved in Iguanodon (i.e. haemal sulcus, Norman, 1980: fig. 45) and ventrally keeled in Delapparentia (Ruiz-Omenaca, 2011). Delapparentia also differs from Iguanodon in the anterior end of the prepubic process (see description). The prepubic process of the pubis of Proa is not dorsoventrally expanded in its anterior end, and the ischial peduncle seems to be dorsally projected (McDonald et al., 2012b: fig. 8) unlike in Delapparentia, where it is posterodorsally projected. The axis and the ilium of Mantellisaurus show differences with respect to those of Delapparentia (see the description and comparison above) and also in the pubis (see holotype NHMUK R5764 in Norman, 2011a: fig. 27.45). Moreover, Ruiz-Omenaca (2011) noted that the first chevron in Delapparentia is located between the third and fourth caudal vertebrae, as in Iguanodon and Ouranosaurus (Taquet, 1976: 119) and unlike Mantellisaurus (Norman, 1986: 310), where it is placed between the second and third caudals. The ilium and ischium of Hypselospinus (Norman, 2010, 2011b) are different from those of Delapparentia. The ischium of Delapparentia (Fig. 2e; Ruiz-Omenaca, 2011: fig. 8) is more angled between the articular surface of the iliac peduncle and the acetabulum border, and this also results in the main axis of the ischial and pubic peduncles forming almost a right angle in Delapparentia, whereas this angle is markedly obtuse in Hypselospinus (Norman, 2011b: fig. 27.37B).
After examining the range of variation within the fossil record, Carpenter and Ishida (2010) noted that the ilium of basal iguanodonts is indeed diagnostic, so it can be used to separate taxa. In fact, the ilium of Delapparentia is useful for distinguishing this taxon from iguanodontoids, but not from Barilium, though there are plenty of differences in the rest of the postcranial elements of these taxa. This advises against the use of ilium morphology as the only criterion in separating taxa.
The possibility of Delapparentia being a junior synonym of Barilium, leaving Delapparentia turolensis as a second species of Barilium, has to be discussed in depth, as Delapparentia presents two characters previously thought to be autapomorphies of Barilium.
First, despite the fragmentary nature of both holotypes there are a considerable number of differential characters within the overlapping material (mainly in the axial skeleton and pubis). As a result of this, the two taxa are not recovered as sister taxa in our analysis, but as close relatives, even if the synapomorphies are coded. Furthermore, a more exhaustive codification of the morphology of the axial skeleton, and other bones such as the pubis, would emphasize the differences between the two taxa.
Secondly, the criteria used to refer material to Barilium in previous papers need to be revised. Norman (2011a) describes NHMUK R3788 (holotype of Sellacoxa pauli; Carpenter and Ishida, 2010) as a compressed and distorted partial postcranial skeleton, and refers it to Barilium cf. dawsoni. However, NHMUK R3788 does not bear the diagnostic rim of the sacrodorsal rib facet visible, in lateral view, in the preacetabular notch, a character present in the ilia of the holotypes of both Barilium dawsoni (Norman, 2011a) and Delapparentia turolensis (this paper). It is a priori difficult to assume that this absence is caused by the possible masking effect of distortion or preservation. On the contrary, this character is actually present in the English Barremian ilium NHMUK R2502 (Norman, 2011b: fig. 27.50), which is the holotype of Iguanodon seelyi and referred to Iguanodon bernissartensis by this author. Furthermore, some of the remains which Norman (2011a) refers to Barilium do not present overlapping material with the holotype, and are referred on the basis of the occurrence of the fossil remains within the same geological unit in geographically close localities, on the assumption that iguanodontian palaeobiodiversity during the Late Jurassic and Early Cretaceous is often represented by robust/large and gracile/small osteological (and taxonomic) pairs. And this would disagree with other proposals (e.g. Paul, 2012). To contextualize the issue, a simplified taxonomic scenario for European iguanodonts is shown in Table 1.
All of the above problems, together with the important difference in age of the two taxa, advise against the synonymization of Barilium and Delapparentia, especially without first-hand examination of the different specimens assigned to Barilium. Nevertheless, this possibility must be considered if future remains of Delapparentia or Barilium are found.
Delapparentia turolensis is a large-sized Barremian basal iguanodont from Spain, which presents an autapomorphic, unusually high axial neural spine and a unique combination of postcranial characters. The ilium morphology differs from that of other basal iguanodonts and relates Delapparentia to the Valanginian Barilium dawsoni from England, with whom it shares two synapomorphies. In our phylogenetic analysis, Delapparentia is recovered in a polytomy with Kukufeldia, Lanzhousaurus, Barilium and the clade equivalent to Iguanodontoidea.
Character scorings for Delapparentia turolensis, to be added to the matrix of McDonald (2012a), McDonald et al. (2012b). Character 110 has been modified to include a new character state (2, scored for Delapparentia and Barilium). With the modification used in this paper, the character reads as follows:
110. Ilium, preacetabular process twisting along its length: twisting absent (0); twisting such that the dorsal surface of the ilium becomes the lateral surface of the cranial end of the process (1); the lateral surface of the preacetabular process twists around its long axis towards its anterior end so that it comes to face almost dorsally (2)
Scoring of Delapparentia: 93 - 1, 94 - 1, 102 - 0, 109 - 1, 110 - 2, 111 - 0, 112 - 2, 115 - 1, 116 - 1, 132 - 0, the rest between 0 and 134 are ?.
This paper is part of the project CGL2010-16447, subsidized by the Spanish Ministerio de Economia y Competitividad, the European Regional Development Fund, and the Government of Aragon (Grupos Consolidados and Direccion General de Patrimonio Cultural). We thank the Museo de Teruel and FCPT-Dinopolis (especially Dr. R. Royo-Torres) for allowing us access to study the Delapparentia holotype. Rupert Glasgow revised the translation of the text into English. Finally, we thank Pascal Godefroit and David B. Weishampel for their helpful reviews.
Bryant, D. (2003): A classification of consensus methods for phylogenetics. In: M.F. Janowitz, F.J. Lapointe, F.R. McMorris, B. Mirkin, F.S. Roberts (eds.), Bioconsensus, DIMACS Series in Discrete Mathematics and Theoretical Computer Science 61. American Mathematical Society, Providence, Rhode Island, pp. 163-184.
Canudo, J.I., Gasca, J.M., Aurell, M., Badiola, A., Blain, H.-A., Cruzado- Caballero, P., Gomez-Fernandez, D., Moreno-Azanza, M., Parrilla, J., Rabal-Garces, R., Ruiz-Omenaca, J.I. (2010): La Cantalera: an exceptional window onto the vertebrate biodiversity of the Hauterivian-Barremian transition in the Iberian Peninsula. Journal of Iberian Geology 36, 295-324. doi: 10.5209/rev_JIGE.2010.v36.n2.8
Canudo, J.I., Gasca, J.M., Moreno, M., Aurell, M. (2012): New information about the stratigraphic position and age of the sauropod Aragosaurus ischiaticus from the Early Cretaceous of the Iberian Peninsula. Geological Magazine 149, 252-263. doi: 10.1017/ S0016756811000732
Carpenter, K., Ishida, Y. (2010): Early and "Middle" Cretaceous iguanodonts in time and space. Journal of Iberian Geology 36, 145-164. doi: 10.5209/rev_JIGE.2010.v36.n2.3
Diaz Molina, M., Yebenes, A. (1987): La sedimentacion litoral y continental durante el Cretacico Inferior. Sinclinal de Galve, Teruel. Estudios geologicos volumen extraordinario Galve-Tremp, 3-21.
Dollo, L. (1888): Iguanodontidae et Camptonotidae. Comptes Rendus de l'Academie des Sciences Paris 106, 775-777.
Fuentes Vidarte, C., Meijide Calvo, M., Meijide Fuentes, F., Meijide Fuentes, M. (2005): Fauna de vertebrados del Cretacico Inferior del yacimiento de "Zorralbo" en Golmayo (Soria, Espana). Revista Espanola de Paleontologia numero extraordinario 10, 83-92.
Galton, P.M. (2012): Hypsilophodon foxii and other smaller bipedal ornithischian dinosaurs from the Lower Cretaceous of southern England. In: P. Godefroit (ed.), Bernissart dinosaurs and Early Cretaceous terrestrial ecosystems. Indiana University Press, Bloomington, pp. 225-281.
Gasca, J.M., Canudo, J.I., Moreno-Azanza, M. (2008): Revision de morfotipos dentales de los iguanodontoideos del Cretacico Inferior de Teruel. Resumenes XXIV Jornadas de la Sociedad Espanola de Paleontologia, Museo del Jurasico de Asturias (MUJA), Colunga, pp. 127-128.
Gasca, J.M., Canudo, J.I., Moreno-Azanza, M. (2009): New iguanodontian dinosaur remains from the Early Barremian of Spain (Castellote, Teruel). Journal of Vertebrate Paleontology 29 (supplement to 3), p. 103A.
Gasca, J.M., Canudo, J.I., Moreno-Azanza, M. (2014): On the diversity of Iberian iguanodont dinosaurs: New fossils from the lower Barremian, Teruel province, Spain. Cretaceous Research 50, 264-272. doi: 10.1016/j.cretres.2014.05.009
Gasulla, J.M., Escaso, F., Ortega, F., Sanz, J.L. (2014): New hadrosauriform cranial remains from the Arcillas de Morella Formation (lower Aptian) of Morella, Spain. Cretaceous Research 47, 19-24. doi: 10.1016/j.cretres.2013.10.004
Gilmore, C.W. (1909): Osteology of the Jurassic reptile Camptosaurus, with a revision of the species of the genus, and a description of two new species. Proceedings of the United States National Museum 36, 197-332.
Godefroit, P., Dong, Z.-M., Bultynck, P., Li, H., Feng, L. (1998): Sino-Belgian Cooperation Program "Cretaceous dinosaurs and mammals from Inner Mongolia"; 1. New Bactrosaurus (Dinosauria, Hadrosauroidea) material from Iren Dabasu (Inner Mongolia, P.R. China). Bulletin de l'Institut royal des Sciences Naturelles de Belgique Sciences de la Terre 68 (supplement), 3-70.
Godefroit, P., Codrea, V., Weishampel, D.B. (2009): Osteology of Zalmoxes shqiperorum (Dinosauria, Ornithopoda), based on new specimens from the Upper Cretaceous of NalaJ-Vad (Romania). Geodiversitas 31, 525-553. doi: 10.5252/g2009n3a3
Goloboff, P.A., Farris, J.S., Nixon, K.C. (2008): TNT, a free program for phylogenetic analysis. Cladistics 24, 774-786. doi: 10.1111/j.10960031.2008.00217.x
Lapparent, A.F. de (1960): Los Dinosaurios de Galve. Teruel 24, 1-21.
Llandres Serrano, M., Vullo, R., Marugan-Lobon, J., Ortega, F., Buscalioni, A. (2013): An articulated hindlimb of a basal iguanodont (Dinosauria, Ornithopoda) from the Early Cretaceous Las Hoyas Lagerstatte (Spain). Geological Magazine 150, 572-576. doi: 10.1017/ S0016756813000095
Marsh, O.C. (1881): Principal characters of American Jurassic dinosaurs. Part V American Journal of Science (Series 3) 21, 167-170.
McDonald, A.T. (2011): The taxonomy of species assigned to Camptosaurus (Dinosauria: Ornithopoda). Zootaxa 2783, 52-68.
McDonald, A.T. (2012a): Phylogeny of basal iguanodonts (Dinosauria: Ornithischia): An update. PLoS ONE 7(5), e36745. doi: 10.1371/journal.pone.0036745
McDonald, A.T. (2012b): The status of Dollodon and other basal iguanodonts (Dinosauria: Ornithischia) from the Lower Cretaceous of Europe. Cretaceous Research 33, 1-6. doi: 10.1016/j.cretres.2011.03.002
McDonald, A.T., Barrett, P.M., Chapman, S.D. (2010a): A new basal iguanodont (Dinosauria: Ornithischia) from the Wealden (Lower Cretaceous) of England. Zootaxa 2569, 1-43.
McDonald, A.T., Kirkland, J.I., DeBlieux, D.D., Madsen, S.K., Cavin, J., Milner, A.R. C., Panzarin, L. (2010b): New basal iguanodonts from the Cedar Mountain Formation of Utah and the evolution of thumbspiked dinosaurs. PLoS ONE 5(11), e14075. doi: 10.1371/journal. pone.0014075
McDonald, A.T., Bird, J., Kirkland, J.I., Dodson, P. (2012a): Osteology of the basal hadrosauroid Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation of Utah. PLoS ONE 7(10), e45712. doi: 10.1371/journal.pone.0045712
McDonald, A.T., Espilez, E., Mampel, L., Kirkland, J.I., Alcala, L. (2012b): An unusual new basal iguanodont (Dinosauria: Ornithopoda) from the Lower Cetaceous of Teruel, Spain. Zootaxa 3595, 61-76. doi: 10.11646/zootaxa.3609.5.8
Norman, D.B. (1980): On the ornithischian dinosaur Iguanodon bernis sartensis from the Lower Cretaceous of Bernissart (Belgium). Me moires de l'Institut royal des Sciences Naturelles de Belgique 178, 1-103.
Norman, D.B. (1986): On the anatomy of Iguanodon atherfieldensis (Ornithischia: Ornithopoda). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique Sciences de la Terre 56, 281-372.
Norman, D.B. (1987): A mass-accumulation of vertebrates from the Lower Cretaceous of Nehden (Sauerland), West Germany. Proceedings of the Royal Society of London B230, 215-255. doi: 10.1098/ rspb.1987.0017
Norman, D.B. (1998): On Asian ornithopods (Dinosauria: Ornithischia). 3. A new species of iguanodontid dinosaur. Zoological Journal of the Linnean Society 122, 291-348. doi: 10.1111/j.1096-3642.1998. tb02533.x
Norman, D.B. (2010): A taxonomy of iguanodontians (Dinosauria: Ornithopoda) from the lower Wealden Group (Cretaceous: Valanginian) of southern England. Zootaxa 2489, 47-66.
Norman, D.B. (2011a): On the osteology of the lower Wealden (Valanginian) ornithopod Barilium dawsoni (Iguanodontia: Styracosterna). Special Papers in Palaeontology 86, 165-194. doi: 10.1111/.14754983.2011.01082.x
Norman, D.B. (2011b): The ornithopod dinosaurs. In: D. Batten (ed.), English Wealden fossils. The Paleontological Association, London, 407-475.
Owen, R. (1842): Report on British fossil reptiles. Part II. Report of Eleventh Meeting of the British Association of the Advancement of Science 11, 60-204.
Paul, G.S. (2008): A revised taxonomy of the iguanodont dinosaur genera and species. Cretaceous Research 29, 192-216. doi: 10.1016/j. cretres.2007.04.009
Paul, G. (2012): Notes on the rising diversity of iguanodont taxa, and iguanodonts named after Darwin, Huxley, and evolutionary science. In: In: P. Huerta Hurtado, F. Torcida Fernandez-Baldor, J.I. Canudo Sanagustin (eds.), Actas V Jornadas Internacionales sobre Paleontologia de Dinosaurios y su Entorno, Salas de los Infantes, Burgos, pp. 123-133.
Pereda-Suberbiola, X., Ruiz-Omenaca, J.I., Torcida Fernandez-Baldor, F., Maisch, M.W., Huerta, P., Contreras, R., Izquierdo, L.A., Montero Huerta, D., Urien Montero, V, Welle, J. (2011): A tall-spined ornithopod dinosaur from the Early Cretaceous of Salas de los Infantes (Burgos, Spain). Comptes Rendus Palevol 10, 551-558. doi: 10.1016/j. crpv.2011.04.003
Ruiz-Omenaca, J.I. (2006): Restos directos de dinosaurios (Saurischia, Ornithischia) en el Barremiense (Cretacico Inferior) de la Cordillera Iberica en Aragon (Teruel, Espana). Unpublished Doctoral Thesis Universidad de Zaragoza, Zaragoza, 439 p. [http://www.aragosaurus. com/secciones/publicaciones/artic/ruizomenaca2006.pdf]
Ruiz-Omenaca, J.I. (2011): Delapparentia turolensis nov. gen. et sp., un nuevo iguanodontoideo (Ornithischia: Ornithopoda) en el Cretacico Inferior de Galve. Estudios geologicos 67, 83-110. doi: 10.3989/ egeol.40276.124
Ruiz-Omenaca, J.I., Canudo, J.I., Aurell, M., Badenas, B., Cuenca-Bescos, G., Ipas, J. (2004): Estado de las investigaciones sobre los vertebrados del Jurasico superior y el Cretacico inferior de Galve (Teruel). Estudios geologicos 60, 179-202. doi: 10.3989/egeol.04603-694
Ruiz-Omenaca, J. I., Canudo, J. I., Cuenca-Bescos, G., Cruzado-Caballero, P., Gasca, J.M., Moreno-Azanza, M. (2012): A new basal ornithopod dinosaur from the Barremian of Galve, Spain. Comptes Rendus Palevol 11, 435-444. doi: 10.1016/j.crpv.2012.06.001
Sanz, J.L., Casanovas, L., Santafe, J.V (1984): Restos autopodiales de Iguanodon (Reptilia, Ornithopoda) del yacimiento de Santa Barbara (Cretacico inferior, Galve, Provincia de Teruel, Espana). Estudios geologicos 40, 251-257. doi: 10.3989/egeol.84403-4666
Sanz, J.L., Buscalioni, A.D., Casanovas, M.L., Santafe, J.V (1987): Di nosaurios del Cretacico Inferior de Galve (Teruel, Espana). Estudios geologicos volumen extraordinario Galve-Tremp, 45-64.
Seeley, H.G. (1887): On the classification of the fossil animals commonly called Dinosauria. Proceedings of the Royal Society of London 43, 165-171.
Sereno, P.C. (1986): Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2, 234-256.
Sereno, P.C. (1991): Lesothosaurus, "fabrosaurids", and the early evolution of Ornithischia. Journal of Vertebrate Paleontology 11, 168-197. doi: 10.1080/02724634.1991.10011386
Swofford, D.L. (2003): PAUP*. Phylogenetic Analysis Using Parsimony (*and Other Methods). Version 4. Sinauer Associates, Sunderland, Massachusetts.
Taquet, P. (1976): Geologie et Paleontologie du gisement de Gadoufaoua (Aptian du Niger). Cahiers de Paleontologie, Editions du Centre National de la Recherche Scientifique, Paris, pp. 1-191.
Wang, X., Pan, R., Butler, R.J., Barret, P.M. (2011): The postcranial skeleton of the iguanodontian ornithopod Jinzhousaurus yangi from the Lower Cretaceous Yixian Formation of western Liaoning, China. Earth and Environmental Science Transactions of the Royal Society of Edimburgh 101, 135-159. doi: 10.1017/S1755691010009266
Weishampel, D.B., Jianu, C.-M., Csiki, Z., Norman, D.B. (2003): Osteology and phylogeny of Zalmoxes (n.g.), an unusual euornithopod dinosaur from the latest Cretaceous of Romania. Journal of Systematic Paleontology 1, 123-143. doi: 10.1017/S1477201903001032
Wiman, J.C. (1929): Die Kreide-Dinosaurier aus Shantung. Palaeontologia Sinica C 6, 1-67.
Winkler, D.A., Murry, P.A., Jacobs, L.L. (1997): A new species of Tenontosaurus (Dinosauria; Ornithopoda) from the Early Cretaceous of Texas. Journal of Vertebrate Paleontology 17, 330-348. doi: 10.1080 /02724634.1997.10010978
You, H., Ji, Q., Li, D. (2005): Lanzhousaurus magnidens gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world. Geological Bulletin of China 24, 785-794.
J.M. Gasca (1) *, M. Moreno-Azanza (1), J.I. Ruiz-Omenaca (1,2), J.I. Canudo (1)
(1) Grupo Aragosaurus-IUCA, Departamento de Ciencias de la Tierra, Facultad de Ciencias, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain.
(2) Museo del Jurasico de Asturias (MUJA), 33328 Colunga, Spain.
e-mail addresses: email@example.com (J.M.G., * corresponding author); firstname.lastname@example.org (M.M.A.); email@example.com (J.I.R.O.); firstname.lastname@example.org (J.I.C.)
Received: 27 December 2013 / Accepted: 18 December 2014 / Available online: 25 March 2015
Table 1.-Simplified overview of European iguanodont distribution, based on Spanish and English Early Cretaceous records. Stage Spain Albian Proa valdearinnoensis Aptian Iguanodon bernissartensis / Barremian cf. Mantellisaurus atherfieldensis Barremian Delapparentia turolensis Hauterivian Valanginian Berriasian Stage England Albian Aptian Iguanodon bernissartensis / Barremian Mantellisaurus atherfieldensis Barremian "Iguanodon seelyi" * Hauterivian Valanginian Hypselospinus fittoni Barilium dawsoni Kukufeldia tilgatensis * Sellacoxa pauli * Berriasian Owenodon hoggii Stage References Albian McDonald et al. (2012b) Aptian Norman (2011b); Llandres / Serrano et al. (2013); Gasulla et Barremian al. (2014) Barremian Norman (2011b); Ruiz-Omenaca (2011) Hauterivian Valanginian Carpenter and Ishida (2010); McDonald et al. (2010a); Norman (2011b) Berriasian Galton (2012) *: Iguanodont taxa with questionable taxonomic validity
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|Title Annotation:||texto en ingles|
|Author:||Gasca, J.M.; Moreno-Azanza, M.; Ruiz-Omenaca, J.I.; Canudo, J.I.|
|Publication:||Journal of Iberian Geology|
|Date:||Jan 1, 2015|
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