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Delapparentia turolensis nov gen et sp., a new iguanodontoid dinosaur (Ornithischia: Ornithopoda) from the Lower Cretaceous of Galve (Spain)
Abstract
An ornithopod dinosaur postcranial skeleton from the Early Cretaceous of Galve (Teruel province, Spain), assigned to Iguanodon bernissartensis by the French paleontologist Albert de Lapparent in 1960, is redescribed. It comes from La Maca 3 locality, early Barremian in age (Camarillas Formation) and it is made of several cervical vertebrae, fragmentary remains of the dorsal and sacral series, several caudal vertebrae, fragments of cervical, dorsal and sternal ribs, fragments of chevrons and ossified tendons, and an incomplete left hip. It has been identified as an "iguanodontid" (i.e., a non-hadrosaurid iguanodontoid) by the presence of a deep prepubic blade and the absence of antitrochanter on ilium. The skeleton represents a new iguanodontoid taxon, Delapparentia turolensis nov. gen et sp., characterized by the following autapomorphies: 1) posterior dorsal ribs with long, parallel and unfused capitulum and tuberculum, 2) ossified sternal ribs, and 3) straight and lateromedially expanded preacetabular process of ilium (convergent in Zalmoxes). It also presents a combination of anterior dorsal ribs with a pneumatic foramen, and a ischium of big size in relation to ilium.
... Until recently, the Early Cretaceous European fossil record of styracosternan iguanodonts was composed of basal representatives of the node-based clade Hadrosauriformes (sensu Sereno [1]), or members of the outgroup. Delapparentia, Hypselospinus, Iguanodon, Mantellisaurus and Proa were the hadrosauriform styracosternans recognized from several Lower Cretaceous formations [2][3][4][5]. A recent re-evaluation of the phylogenetic relationships indicates a new subclade of non-hadrosauriform styracosternans ('iguanodontoids') and includes most of these previously considered European hadrosauriforms. ...
... Presently, the Lower Cretaceous Iberian styracosternan iguanodontians species are the lower Barremian Delapparentia turolensis [2] and Iguanodon galvensis [5], the upper Barremian Iguanodon bernissartensis and Mantellisaurus atherfieldensis [7][8][9][10], and the lower Albian Proa valdearinnoensis [3]. However, it should be noted that Norman [6] considers Delapparentia turolensis provisionally as a nomem dubium. ...
... A similar medioventral flange to that of Hypselospinus is present in the ilium of Lurdusaurus arenatus [25]. As in Hypselospinus fittoni (NHMUK R1834), Iguanacolossus fortis [23], Lurdusaurus arenatus [25] and Ouranosaurus nigeriensis [27], the preacetabular process of the ilium in Morelladon is transversely compressed and oriented vertically, differing from the lateral torsion shown by Barilium dawsoni [21], Bolong yixianensis [21], Delapparentia turolensis [2], Iguanodon bernissartensis [4,18], Iguanodon galvensis [5], Mantellisaurus atherfieldensis [4,19] and Proa valdearinnoensis [6]. In Morelladon the ischiadic peduncle of the ilium is strongly expanded laterally and stepped as in Barilium dawsoni [21], Hypselospinus fittoni [6] and Mantellisaurus atherfieldensis [19]. ...
A new styracosternan ornithopod genus and species is here described based on a partial postcranial skeleton and an associated dentary tooth of a single specimen from the Arcillas de Morella Formation (Early Cretaceous, late Barremian) at the Morella locality, (Castellón, Spain). Morelladon beltrani gen. et sp. nov. is diagnosed by eight autapomorphic features. The set of autapomorphies includes: very elongated and vertical neural spines of the dorsal vertebrae, midline keel on ventral surface of the second to fourth sacral vertebrae restricted to the anterior half of the centrum, a posterodorsally inclined medial ridge on the postacetabular process of the ilium that meets its dorsal margin and distal end of the straight ischial shaft laterally expanded, among others. Phylogenetic analyses reveal that the new Iberian form is more closely related to its synchronic and sympatric contemporary European taxa Iguanodon bernissartensis and Mantellisaurus atherfieldensis, known from Western Europe, than to other Early Cretaceous Iberian styracosternans (Delapparentia turolensis and Proa valdearinnoensis). The recognition of Morelladon beltrani gen. et sp. nov. indicates that the Iberian Peninsula was home to a highly diverse medium to large bodied styracosternan assemblage during the Early Cretaceous.
... or Iguanodontoidea indet. (e.g., Ruiz-Omeñaca et al., 1998, 2004Ruiz-Omeñaca andCanudo, 2003, 2004;Torcida Fernández-Baldor et al., 2006;Contreras-Izquierdo et al., 2009;Ruiz-Omeñaca, 2011). Recent studies have led to the description and assignation of these ornithopod remains to the clade Iguanodontoidea non-Hadrosauridae (sensu Norman, 2002Norman, , 2004. ...
... or Iguanodontoidea indet. (e.g., Ruiz-Omeñaca et al., 1998, 2004Ruiz-Omeñaca andCanudo, 2003, 2004;Torcida Fernández-Baldor et al., 2006;Contreras-Izquierdo et al., 2009;Ruiz-Omeñaca, 2011). Recent studies have led to the description and assignation of these ornithopod remains to the clade Iguanodontoidea non-Hadrosauridae (sensu Norman, 2002Norman, , 2004. ...
... Ruiz-Omeñaca and Canudo (2003) presented a comprehensive synthesis of the ornithischian dinosaurs from the Lower Cretaceous (HauterivianeAptian) of the Iberian Peninsula, referring to the existence of remains of hypsilophodontids, dryosaurids, iguanodontids, possible heterodontosaurids and ?hadrosauroids. Iguanodon bernissartensis Boulenger, 1881 and Delapparentia turolensis Ruiz-Omeñaca, 2011 from the Spanish Lower Cretaceous dinosaur osteological record are accepted as Iguanodontoidea species (e.g., Sanz et al., 1982;Gasulla et al., 2009;Ruiz-Omeñaca, 2011). The synthesis presented by Ortega et al. (2006) considered that ornithopods like hypsilophodontids, dryosaurids and iguanodontids (Iguanodon) are represented in the Lower Cretaceous of the Iberian Peninsula and that Iguanodon, represented by Iguanodon bernissartensis, was probably the most common dinosaur in Barremian and Aptian times. ...
... The preacetabular process of the ilium projects cranioventrally and terminates in a horizontal boot that is offset from and forms an obtuse angle with the ventral margin of the process (Fig. 31A, B), as in Iguanacolossus [7], Cedrorestes [6], Planicoxa [4], Osmakasaurus depressus [5,39], Barilium [58], Iguanodon bernissartensis [29], Mantellisaurus [30], Delapparentia [55], Ouranosaurus [26], Xuwulong [35], and Probactrosaurus gobiensis [13]. A prominent shelf originates on the medial surface of the preacetabular process dorsal to the horizontal boot; this shelf expands caudally until it comprises the entire medial surface of the preacetabular process where the process merges with the body of the ilium (Fig. 31B). ...
... The dorsal margin of the ilium is straight dorsal to the pubic peduncle and acetabulum (Fig. 31A). The dorsal margin thickens caudally to form a laterally everted rim dorsal to the ischial peduncle (Fig. 31A), as in Iguanodon bernissartensis [29], Mantellisaurus [30], Delapparentia [55], Ouranosaurus [26], Altirhinus [32], Jinzhousaurus [56], Xuwulong [35], and Probactrosaurus gobiensis [13]. Caudal to this laterally everted rim, the dorsal margin of the postacetabular process abruptly slopes caudoventrally to form a well demarcated platform for the origin of M. iliocaudalis. ...
... The cranial pubic process is expanded, with dorsal and ventral margins that diverge towards its cranial end (Fig. 31C, D), as in Lurdusaurus [54], Barilium [58], Lanzhousaurus [47], Iguanodon bernissartensis [29], Mantellisaurus [30], Delapparentia [55], Ouranosaurus [26], Altirhinus [32], Xuwulong [35], ''Probactrosaurus'' mazongshanensis [42], Probactrosaurus gobiensis [13], Bactrosaurus [38], Gilmoreosaurus [40], Levnesovia [36], Tethyshadros [37], Huehuecanauh-tlus [59], and hadrosaurids [48]. The ventral margin of the cranial pubic process is gently convex, whereas the dorsal margin is strongly concave. ...
Eolambia caroljonesa is known from copious remains from the lower Cenomanian Mussentuchit Member of the Cedar Mountain Formation in eastern Utah; however, the taxon has been only briefly described. Thus, we present herein a complete osteological description of Eolambia.
The description of Eolambia presented here is based upon the holotype partial skeleton (CEUM 9758), paratype partial skull (CEUM 5212), and abundant disarticulated elements from two bonebeds that contain juvenile individuals. These remains allow the skeletal anatomy of Eolambia to be documented almost fully and a revised diagnosis to be proposed.
The description provided here facilitates comparisons between Eolambia and other iguanodontians and allows Eolambia to be coded for additional characters in phylogenetic analyses. The close affinity between Eolambia and Probactrosaurus gobiensis from the Early Cretaceous of China supports previous hypotheses of faunal interchange between Asia and North America in the early Late Cretaceous.
... 5. How individual variation can affect iguanodontian systematics: the case of 'Delapparentia turolensis' Ruiz-Omeñaca 2011 Lapparent (1960) recognized the presence of I. bernissartensis in the lower Barremian from Galve (Teruel, Spain) based on the partial postcranial skeleton of a large individual that included several vertebrae and ribs and parts of the ilium, pubis and ischium. More recently, Ruiz-Omeñaca (2011) proposed that this material is sufficiently different from that of I. bernissartensis and should be included in a new taxon, 'Delapparentia turolensis'. An isolated dentary (MPZ 2014/329) and an ischium (MPZ 2014/328), also from the lower Barremian of Teruel (Spain), were subsequently referred to this taxon (Gasca et al., 2014). ...
... An isolated dentary (MPZ 2014/329) and an ischium (MPZ 2014/328), also from the lower Barremian of Teruel (Spain), were subsequently referred to this taxon (Gasca et al., 2014). Given the ambiguity of the first diagnosis proposed by Ruiz-Omeñaca (2011) for 'D. turolensis', Norman (2015 suggests that this taxon should provisionally be considered a nomen dubium. ...
At the end of nineteenth century, approximately thirty nearly complete skeletons of the ornithopod dinosaur Iguanodon bernissartensis were discovered in Lower Cretaceous deposits in Bernissart (Belgium). Because most of the specimens are approximately the same size, they offer a unique opportunity for studying individual variation (i.e., differences among individuals of the same or roughly the same age) in iguanodontians. Here, we report the results of a study combining both morphometric and visual analyses of the postcranial skeleton of the Bernissart specimens. We found significant individual variation in the morphology of the axis, sacrum, caudal vertebrae, scapula, humerus, pollex, ilium, ischium, femur, and tibia. No definitive evidence of sexual dimorphism was identified in I. bernissartensis. Individual variation in I. bernissartensis has significant implications for phylogenetic and ontogenetic studies as well as for evaluating diagnostic characters in Iguanodon and other iguanodontians. For example, the status of the basal styracosternan ‘Delapparentia turolensis’ from the lower Barremian of Spain is discussed; given the individual variation in the postcranial skeleton of I. bernissartensis, it is in fact impossible to distinguish ‘Delapparentia’ from Iguanodon species based on the available material.
... In the Iberian Peninsula, remains of basal Hadrosauriformes have been cited in several Lower Cretaceous formations (Antunes and Mateus, 2003;Fuentes Vidarte et al., 2005;Gasulla, 2005;Ortega et al., 2006;Ruiz-Omeñaca, 2011;McDonald et al., 2012a;Pereda-Suberbiola et al., 2012;Llandres Serrano et al., 2013). Currently, the Iberian fauna of basal Hadrosauriformes is composed of four taxa, Delapparentia turolensis, Iguanodon bernissartensis, Mantellisaurus atherfieldensis and Proa valdearinnoensis (Sanz et al., 1982;Gasulla et al., 2009;Ruiz-Omeñaca, 2011;McDonald et al., 2012a;Llandres Serrano et al., 2013). ...
... In the Iberian Peninsula, remains of basal Hadrosauriformes have been cited in several Lower Cretaceous formations (Antunes and Mateus, 2003;Fuentes Vidarte et al., 2005;Gasulla, 2005;Ortega et al., 2006;Ruiz-Omeñaca, 2011;McDonald et al., 2012a;Pereda-Suberbiola et al., 2012;Llandres Serrano et al., 2013). Currently, the Iberian fauna of basal Hadrosauriformes is composed of four taxa, Delapparentia turolensis, Iguanodon bernissartensis, Mantellisaurus atherfieldensis and Proa valdearinnoensis (Sanz et al., 1982;Gasulla et al., 2009;Ruiz-Omeñaca, 2011;McDonald et al., 2012a;Llandres Serrano et al., 2013). ...
This article describes isolated skull bones of at least three ornithopod dinosaurs from the lower Aptian “Arcillas de Morella” Formation at Morella (Castellón, Spain). These bones correspond to two right maxillae and a partial left quadrate. Analysis of the two maxillae belonging to the large-sized European ornithopod Iguanodon bernissartensis provided new information about this taxon. Hence, for the first time in Iguanodon, a rostrodorsal process and a straight shape, both in the maxilla and in the tooth row, are described when viewed dorsally and occlusally, respectively. Regarding the left quadrate, in the lateral and medial views, the presence of a bowed quadrate shaft related the left quadrate to the monospecific genus of large-sized ornithopod from the European Early Cretaceous Mantellisaurus. Given the scarce information about the left quadrate, we tentatively refer this bone to cf. Mantellisaurus atherfieldensis. Furthermore, new evidence of these Hadrosauriformes in the Iberian Peninsula corroborates the great similarity between the Barremian–early Aptian dinosaur faunas in British, Belgium and Iberian records.
... Vertebral ankyloses is a vertebral joint disease commonly described in dinosaurs (Rega, 2012 and references therein), including ornithopods (e.g., Witzmann et al., 2008;Ruiz-Omeñaca, 2011). It involves the co-ossification of two (or more) vertebrae (usually through the fusion of their centra) due to congenital reasons, trauma, or physiological disorders (Cisneros et al., 2010). ...
The early Barremian Iberian ornithopod Iguanodon galvensis was described for the first time in 2015. However, much of its anatomy, such as the axial skeleton in mature specimens, remains unknown. Here, the partially articulated presacral vertebrae and ribs belonging to a large adult ornithopod (DS-1 ornithopod) from the lower Barremian (Lower Cretaceous) that were found in Teruel Province (northeast of the Iberian Peninsula, Spain) are investigated by a systematic study and a phylogenetic analysis. The only cervical vertebra preserved is strongly opisthocoelus, as is typical of styracosternans. In fact, the phylogenetic analysis resolves DS-1 ornithopod as an hadrosauriform styracosternan. The assemblage also includes ten anterior-to-posterior dorsal vertebrae that strongly resemble those of the contemporary European iguanodontoid Iguanodon, particularly in having amphiplatyan and higher-than-long centra and dorsal neural spines two times the lateral height of their centra and slightly sigmoid in the posterior vertebrae. In addition, the dorsal centra are moderately compressed between the articular faces and lack a ventral keel, unlike the late Barremian type species I. bernissartensis but resembling the sympatric I. galvensis. For these reasons, DS-1 ornithopod is ascribed here as I. cf. galvensis. Moreover, this specimen has costovertebral ankyloses likely related to the specimen’s maturity. Finally, the fossils of I. galvensis including those referred to it as DS-1 ornithopod, as well as evidence provided by bones and tracks in other places, indicate that the genus Iguanodon frequently occupied areas around rivers, lakes, estuaries, or lagoons.
... Based on current knowledge, the diversity of this type of dinosaur (all of which are considered Styracosterna) in this stratigraphic range is composed of Magnamanus soriaensis Fuentes et al., 2016 in the upper Hauterivian-lower Barremian of Soria province (Fuentes et al., 2016); Iguanodon galvensis Verdú et al., 2015 in the lower Barremian of Teruel province (Verdú et al., 2015); Iguanodon bernissartensis Boulenger in Van Beneden, 1881, Mantellisaurus atherfieldensis (Hooley, 1925), and Morelladon beltrani Gasulla et al., 2015 in the upper Barremian of Cuenca (with the exception of the last taxon) and Castellón provinces (Sanz et al., 1982;Llandres et al., 2013;Gasulla et al., 2014Gasulla et al., , 2015Gasulla, 2015;Sanguino & Buscalioni, 2018); and Proa valdearinnoensis McDonald et al., 2012 in the Albian of Teruel province (McDonald et al., 2012). In addition, another styracosternan described in the lower Barremian of Teruel province, 'Delapparentia turolensis' Ruiz-Omeñaca, 2011, is generally considered a nomen dubium (Norman, 2015;Verdú et al., 2017). ...
We report some large ornithopod vertebrae from two upper Hauterivian-lower Barremian (Lower Cretaceous) localities in El Castellar (Maestrazgo Basin, Teruel, Spain). These fossils have been studied systematically as well as morphometrically using a multivariate analysis in order to analyse the diversity of the sample. In fact, principal component analysis has been demonstrated as an useful tool for establishing affinities in isolated iguanodontian vertebrae, at least when size effect is not removed from the analysed dataset. As result of this study, two large indeterminate styracosternans are distinguished in the sample: a large one with platycoelus anterior caudal vertebrae related to the genera Magnamanus and Iguanodon, and a middle-sized one with longer-than-high dorsal vertebrae and amphicoelus anterior caudal vertebrae related to Morelladon. Such diversity of large ornithopods observed in the upper Hauterivian-lower Barremian of the Maestrazgo Basin is similar to that previously observed in western Cameros Basin and it demonstrates the presence of at least two different forms of styracosternan in this stratigraphic range of the Iberian Peninsula.
... The Camarillas Formation is composed of red or variously colored shaley silts and clays, sandstones (non-channelled sediments, overbank deposits), and mainly white sands and gravels (paleochannels), with occasional marl and limestone intercalations (Fig. 4). The depositional environment of the Camarillas Formation in the Galve sub-basin is the Ornamented with pits, no sulcus, and roundly end ( The vertebrate assemblage of the Camarillas Formation at Galve consists of sharks, bony fishes, amphibians, squamates, crocodyliforms, turtles, dinosaurs and mammals (Ruiz-Omeñaca et al., 2004Badiola, Canudo & Cuenca-Bescós, 2011;Ruiz-Omeñaca, 2011;Pérez-García, Scheyer & Murelaga, 2013;Verdú et al., 2015). Archosaurs are diverse and apart from neosuchian crocodyliforms, include a new iguanodontian genus and species, "Delapparentia turolensis" (Ruiz-Omeñaca, 2011), which has been considered as an undetermined species of Iguanodon (Verdú et al., 2017), and the species I. galvensis . ...
Background
The neosuchian crocodyliform genus Hulkepholis constitutes the longirostral lineage of the European Goniopholididae. It comprises two species ranging from the Valanginian of southern England to the lower Albian of the northern Teruel (Spain). A new species of Hulkepholis is described based on a partially complete skull from the lower Barremian Camarillas Formation. We investigate its phylogenetic position and the palatal patterns among members of Goniopholididae and the closely related Thalattosuchia and Tethysuchia.
Methods
Phylogenetic relationships were investigated with two matrices using a previously published dataset as the basis: the first differed only by the addition of the new species, the second had newly discovered states for 11 characters, the new species plus several additional specimens of Hulkepholis and Anteophthalmosuchus . Both matrices were processed using TNT v. 1.1, in a heuristic analysis of maximum parsimony, with tree bisection and reconnection 1,000 random addition replicates and saving the 10 most parsimonious trees per replicate, and up to 10 suboptimal trees to calculate Bremer supports. The skull geometry of nine species from Thalattosuchia, Tethysuchia and Goniopholididae was explored to test shape variation between the rostral and postrostral modules, and to visualize the differences on the secondary palate. A set of 18 landmarks was used to delimit significant anatomical features, and the skulls were isotropically scaled using Adobe Illustrator, with the longest skull ( Sarcosuchus imperator ) as the baseline for comparison.
Results
The European lineages of goniopholidids are two clades ( Nannosuchus + Goniopholis ) plus ( Hulkepholis + Anteophthalmosuchus ). The new species, Hulkepholis rori sp. nov, shares with the latter clade the following apormorphies: a long anterolateral postorbital process, postorbital process almost reaching the anterior jugal ramus, and basioccipital tubera with lateral edges turned posteriorly. Anteophthalmosuchus was found to be monophyletic, and Hulkepholis paraphyletic due to the poor preservation of H. willetti . Hulkepholis rori is distinguished by having vascular fossae and a mid-protuberance on the ventral surface of the basioccipital, and wide internal fossae in the quadrate. Among Goniopholididae differences on the secondary palate are the presence of a palatal cleft, the narrowness of the secondary choana, and a wide foramen of the median pharyngeal tube.
Conclusions
The new species is the earliest Hulkepholis from the Iberian Peninsula. New characters have been recognized in the organization of the palate and in the occipital region raising unexpected questions on the evolution of Goniopholididae. The set of palatal characters is discussed as part of a singular palatogenesis in Goniopholididae. The protruding occipital areas suggest that the longirostral Hulkepholis would have had an aquatic lifestyle with particular neck and skull movements.
... The Barremian-Aptian (Lower Cretaceous) sedimentary rocks of the Iberian Peninsula are rich in dinosaur fossil remains. Several discoveries have been made in Portugal (e.g., Lapparent and Zbyszewski 1957;Antunes and Mateus 2003;Mateus et al. 2011a;Figueiredo et al. 2015) and, especially, in Spain (e.g., Lapparent 1966;Sanz et al. 1982Sanz et al. , 1988Sanz et al. , 1996Sanz and Buscalioni 1992;Pérez-Moreno et al. 1994;Pereda Suberbiola et al. 2003, 2012Ruiz Omeñaca and Canudo 2003;Ortega et al. 2006Ortega et al. , 2010Canudo et al. 2008;Gasulla et al. 2011aGasulla et al. , b, 2012Gasulla et al. , 2014Gasulla et al. , 2015Ruiz-Omeñaca 2011;McDonald et al. 2012;Royo-Torres et al. 2012;Kirkland et al. 2013;Verdú et al. 2015). Although sauropods are a relatively common group of dinosaurs, the first partial skeletons from the Iberian Peninsula were not found until the end of the twentieth century (e.g., Sanz et al. 1982;Pereda Suberbiola et al. 2003;Fuentes Vidarte et al. 2005;Canudo et al. 2008;Gasulla et al. 2008Gasulla et al. , 2010Royo-Torres et al. 2012;Fernández-Baldor et al. 2013). ...
Purpose and methods
Since the second half of the 19th century, the Arcillas de Morella Formation (late Barremian) has yielded abundant vertebrate fossil material from several outcrops of the Morella region (Maestrat Basin, Castellón, eastern Spain). Several historical specimens of fossil reptiles, so far unpublished or not studied in detail, are housed in the Museo Nacional de Ciencias Naturales in Madrid (Spain). In fact, many of the first dinosaur specimens discovered in Spain, from Morella, are part of the vertebrate palaeontology collection of that institution. Herein, this sauropod material is described and discussed in order to study the diversity of the sauropod fauna during the late Barremian on the Maestrat Basin.
Results
The specimens include both axial and appendicular elements. The systematic study of this material suggests the presence of indeterminate titanosauriforms, some of which have somphospondylan and ‘laurasiform’ affinities. Comparative analysis of two isolated humeri from Morella (MNCN 59703 and MNCN 68484) and a humerus subsequently found in this area, indicates the presence of three titanosauriform taxa in the upper Barremian of the Maestrat Basin, two of which have somphospondylan affinities.
Conclusions
The sauropod diversity of the Arcillas de Morella Formation recognized herein, in particularly considering the titanosauriforms, is greater than that previously considered, at least three taxa.
... FMNH PR 3847 includes the nearly complete left pubis and the right pubis missing most of the distal end of the cranial pubic process (Fig 1). The distal end of the cranial pubic process is dorsoventrally expanded, as in Lurdusaurus [79], Barilium [81], Hypselospinus [58], Lanzhousaurus [80], Iguanodon [61], Mantellisaurus [62], Delapparentia [85], Ouranosaurus [59], Altirhinus [67], Bolong [44], Xuwulong [69], Gongpoquansaurus [75,76], Probactrosaurus [65], Bactrosaurus [72], Gilmoreosaurus [74], Levnesovia [13], Tethyshadros [71], Huehuecanauhtlus [23], and hadrosaurids [7]. The dorsoventral expansion of the cranial pubic process is asymmetrical, with the ventral margin more expanded than the dorsal, giving the dorsoventral expansion an apparent cranioventral inclination (Fig 9E). ...
Background
Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit Member of the Cedar Mountain Formation of Utah, and one of the most completely known non-hadrosaurid iguanodontians from North America. In addition to the large holotype and paratype partial skulls, copious remains of skeletally immature individuals, including three bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the lack of associated postcranial material of larger, more mature individuals.
Methodology/Principal findings
Here we describe a recently discovered associated partial postcranial skeleton of a large Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age. Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay deposit, along with an unusual abundance of small crocodylomorph material.
Conclusions/Significance
FMNH PR 3847 provides a wealth of new morphological data, adding to the anatomical and systematic characterization of Eolambia caroljonesa, and histological data, revealing new information on growth history in a basal hadrosauromorph. Taphonomic characterization of FMNH PR 3847 and associated vertebrate material will allow comparison with other vertebrate localities in the Mussentuchit Member of the Cedar Mountain Formation.
... lished version of the McDonald matrix for iguanodontians (McDonald, 2012b; McDonald et al., 2012b) (see below). Some characters of the taxa I. bernissartensis (16 (0), 110 (1)) (Norman, 2012; 2014a,b), D. turolensis (93 (1), 101 (1), 102 (0), 110(1))(Ruiz-Omeñaca, 2011;Gasca et al., 2015) and Proa valdearinnoensis ( ...
Although Iguanodon is one of the most abundant and well-known of Europe's dinosaur genera, fossils of young specimens are very rare. Indeed, the fossil record contains very few examples of the young of any non-hadrosaurid iguanodontian. Here we report the discovery of 13 Iguanodon perinates from the Lower Cretaceous of Galve (Teruel, Spain). The characteristics of an adult and juvenile found nearby show these perinates to belong to a new species: Iguanodon galvensis sp. nov. The histological and osteological features of these young animals indicate them to have been in their first year of life. The taphonomic features of their remains, plus the finding of clearly embryonic vertebrae alongside them, suggest the perinates of this species remained in the vicinity of their nests for some time, possibly congregating in nursery areas.
... The last sedimentological data from the middleeupper part of this formation indicate a mixed-carbonate siliciclastic back-barrier system influenced by synsedimentary faults (Navarrete et al., 2013 ). The Camarillas Formation in the Galve Sub-basin has numerous vertebrate localities with dinosaur fossil remains (Ruiz Omeñaca et al., 2012; Ruiz Omeñaca 2011 ). There are abundant ornithopod dinosaurs (Delapparentia , Gideonmantellia), albeit herbivores such as Sauropoda and Thyreophora are scarce. ...
A set of samples from the Camarillas Formation (Barremian,Weald facies) in the Galve Sub-basin (Central Iberian Chain, north-east Spain) was studied to determine the origin of the abundant kaolinitic clays and
their relationship to the sedimentary environment, palaeoclimate and diagenetic processes. The samples
were examined by X-ray diffraction and scanning and transmission electron microscopy, with special
emphasis on clay-mineral characterization. The analysed materials are a mixture of detrital (quartz,
micas, and K-feldspars) and authigenic phases (kaolinite, Fe-oxides, gibbsite, dickite, and calcite).
Therefore, the mineralogy of the rocks reflects the source area, the sedimentary conditions, and the
diagenetic evolution. The most abundant authigenic phases are kaolinites. The combination of XRD and
electron microscopy shows that the kaolinites are well crystallized and have as high a degree of ordering
as those formed by weathering in palaeosols; this clay formed the rock matrix, intergrowths with
muscovite, and vermicular booklets that replaced detrital silicates as a consequence of intense dissolution
processes. The diagenetic processes have recrystallized kaolinites in the sandstones, producing
larger crystallinity indices and dickite. In contrast, kaolinites from the claystones and siltstones probably
reflect formation by weathering. The kaolinitization process described, associated with the crystallization
of gibbsite and iron oxides, is in agreement with the relatively warm and humid conditions described for
the Iberian Range basin in the early Barremian.
... Compelling evidence of PSP is now known in early representatives of both clades, and patterns of pneumatization in derived pterosaurs, sauropods, and non-avian theropods are diagnostic for the air sacs required for flow-through lung ventilation [7,[12][13][14][15]. The discovery of more pneumaticity in pterosaurs, sauropodomorphs, and non-avian theropods emphasises how strange is the absence of reported pneumaticity in ornithischians ( [16]: p. 19; the putative pneumatic foramen in a dorsal rib of the iguanodont Delapparentia [86] is not convincing). If, as seems increasingly likely, an air sac system is primitive for Ornithodira, why did ornithischians never discover PSP (in a developmental sense)? ...
Skeletal pneumaticity is found in the presacral vertebrae of most sauropod dinosaurs, but pneumaticity is much less common in the vertebrae of the tail. We describe previously unrecognized pneumatic fossae in the mid-caudal vertebrae of specimens of Giraffatitan and Apatosaurus. In both taxa, the most distal pneumatic vertebrae are separated from other pneumatic vertebrae by sequences of three to seven apneumatic vertebrae. Caudal pneumaticity is not prominent in most individuals of either of these taxa, and its unpredictable development means that it may be more widespread than previously recognised within Sauropoda and elsewhere in Saurischia. The erratic patterns of caudal pneumatization in Giraffatitan and Apatosaurus, including the pneumatic hiatuses, show that pneumatic diverticula were more broadly distributed in the bodies of the living animals than are their traces in the skeleton. Together with recently published evidence of cryptic diverticula-those that leave few or no skeletal traces-in basal sauropodomorphs and in pterosaurs, this is further evidence that pneumatic diverticula were widespread in ornithodirans, both across phylogeny and throughout anatomy.
... NHMUK R3741 (cf. Mantellisaurus in McDonald [21]; considered to represent a possible distinct taxon by Carpenter and Ishida [22]) was coded as a separate OTU, and four new taxa were added: Delapparentia [23], Ratchasimasaurus [24], Xuwulong [25], and Glishades [26]. Finally, the coding of character 112 (ilium, morphology of dorsal margin of postacetabular process dorsal to ischial peduncle) for Iguanacolossus was changed from 1 (laterally bulging eminence dorsal to ischial peduncle, no modification of dorsal margin) to 2 (mediolaterally thickened dorsal margin compared to dorsal margin above pubic peduncle) upon reconsideration of the morphology of the ilium [following discussion with J. I. Kirkland, pers. ...
The precise phylogenetic relationships of many non-hadrosaurid members of Iguanodontia, i.e., basal iguanodonts, have been unclear. Therefore, to investigate the global phylogeny of basal iguanodonts a comprehensive data matrix was assembled, including nearly every valid taxon of basal iguanodont. The matrix was analyzed in the program TNT, and the maximum agreement subtree of the resulting most parsimonious trees was then calculated in PAUP. Ordering certain multistate characters and omitting taxa through safe taxonomic reduction did not markedly improve resolution. The results provide some new information on the phylogeny of basal iguanodonts, pertaining especially to obscure or recently described taxa, and support some recent taxonomic revisions, such as the splitting of traditional "Camptosaurus" and "Iguanodon". The maximum agreement subtree also shows a close relationship between the Asian Probactrosaurus gobiensis and the North American Eolambia, supporting the previous hypothesis of faunal interchange between Asia and North America in the early Late Cretaceous. Nevertheless, the phylogenetic relationships of many basal iguanodonts remain ambiguous due to the high number of taxa removed from the maximum agreement subtree and poor resolution of consensus trees.
Ornithopod remains are reported from the Papo-Seco Formation (lower Barremian, Early Cretaceous) at Cape Espichel, south of Lisbon, in western central Portugal. The fossil material comes from the Boca do Chapim, Praia do Areia do Mastro and Praia do Guincho palaeontological sites. Some fossils are known from the 19th century and the beginning of the 20th century and other remains have been recently collected. Ornithopod and other vertebrate remains from the Papo-Seco Formation occur in limestones, marls, sandstones and conglomerates in a succession interpreted as being deposited in lagoonal and estuarine environments. A study of the available palaeontological material, including teeth and postcranial remains, suggests the presence of a large styracosternan-like iguanodontian, but does not allow confirmation of the occurrence of Iguanodon or Mantellisaurus. Ornithopod remains from the Papo-Seco Formation are provisionally assigned to Ornithopoda indet., Iguanodontia indet. and cf. Styracosterna indet., increasing the record of Portuguese ornithopods of early Barremian age.
The present study focuses on a new record of freshwater bivalves from the lower Barremian Camarillas Formation of the Lower Cretaceous of Teruel, eastern Spain. A new genus Monginaia is described and included in a new family Monginaiidae (Unionida). This taxon is compared and contrasted with other European, Asiatic and North American species. This discovery provides new palaeogeographic data on the distribution and origin of the Unionida in Europe. Moreover, this taxon is an effective tool for the environmental reconstruction of the Spanish Cretaceous ecosystem where it coexisted with dinosaurs and crocodiles and other vertebrates.
A new genus and species of non-hadrosaurid hadrosauriform dinosaur, Brighstoneus simmondsi gen. et sp. nov., is described from the Lower Cretaceous Wessex Formation of the Isle of Wight. The new taxon has two autapomorphies, a nasal having a modest nasal bulla with convex sides, and primary and accessory ridges on the lingual aspect of the maxillary crown. The dentary has at least 28 alveolar positions, which is the highest number recorded in an ornithopod with non-parallel sided alveoli, creating a character combination that is unique within Iguanodontia. The hadrosauriform fauna of the Barremian–Aptian Wealden Group on both the Isle of Wight and mainland England has been represented for almost a century by just two taxa, the robust Iguanodon bernissartensis and the more gracile Mantellisaurus atherfieldensis, with referred material often being fragmentary or based on unassociated elements. This discovery increases the known hadrosauriform diversity in England and, together with recent discoveries in Spain, suggests that their diversity in the upper Wealden of Europe was considerably wider than initially realized. This find also has important implications for the validity of the Mantellisaurus atherfieldensis hypodigm, and a reassessment of existing material is suggested.
http://zoobank.org/urn:lsid:zoobank.org:pub:31F0D48F-C1DA-406E-A811-1F5937ED19F4
A review of the onset of the synrift sedimentation and synsedimentary extensional tectonics of the Oliete sub-basin (north- western Maestrazgo basin, East Spain) is presented here based on new data acquired after extensive sedimentological, struc- tural and palaeontological analysis of the Barremian Blesa Fm. The lower boundary of the Blesa Fm is a prominent basal synrift unconformity overlying Jurassic units. This formation has been divided into three genetic stratigraphic sequences bounded by sub-basin-wide unconformities. The lower Blesa sequence (LBS) is characterized by distal alluvial to palustrine marls/clays grading upward to palustrine–lacustrine limestones. The LBS is bounded on top by a planar to irregular trans- gressive, hardened ferruginous surface, locally encrusted by oysters. Above this discontinuity, the middle Blesa sequence consists of oyster-rich limestones and marls deposited in a shallow restricted bay, which grade to distal alluvial and palus- trine–lacustrine marls/clays and limestones towards the marginal areas of the basin. The boundary between the middle and upper Blesa sequence (UBS) is a regressive surface outlined by the local presence of an erosive conglomeratic bed. The UBS generally starts with red clays deposited in distal alluvial fan environments, which grade upwards to palustrine and lacustrine carbonates and marls/clays. The local presence of heterolithic alternations of clay with ne-to-medium sandstone and of cross-bedded sandstones indicates the local occurrence of siliciclastic coastal environments in the UBS. The upper bound- ary of the Blesa Fm is marked by widespread transgression, giving rise to the bioclastic limestones of the Alacón Fm. In the present paper, the stratigraphic position and palaeoenvironmental context of the abundant vertebrate remains found across the de ned sequences within the Blesa Formation is reviewed. The results obtained are relevant for a further understanding of the tectosedimentary evolution of the studied basin. Successive stages of evolution are distinguished, including the initial uplift, breakup and erosion of the earlier Jurassic carbonate platform that took place during the Tithonian–Hauterivian; the onset of synrift sedimentation during the early Barremian, which was highly controlled by extensional faulting and di eren- tial block subsidence; the homogenization of the basin subsidence accompanied by the incursion of marine waters (sourced from southeastern areas) during the middle part of the Barremian; and the signi cant fall in base level, of possible climatic origin and also involving signi cant siliciclastic input in the northern areas of the Oliete sub-basin around the middle part of the late Barremian.
Introduction: Barranco del Hocino-1 is a new fossil site located near Estercuel, Teruel province, Spain. The fossil site is located geologically within the Oliete sub-basin, in the Blesa Formation (Barremian in age). Barranco del Hocino-1 shows a diverse assemblage of tetrapod vertebrates similar to other sites in the Blesa Formation. Materials and methods: Six isolated teeth belonging to Theropoda have been found. A study of their qualitative and quantitative characters, along with statistical (DFA) and cladistic analyses, enable us to identify four different dental morphotypes. Results: These morphotypes belong to separate tetanuran theropod taxa. One is related to Spinosauridae. The other morphotypes show affinities with non-spinosaurid tetanurans, probably related to Carcharodontosauria. Conclusions: The results are congruent with the known theropod record of the Iberian Peninsula and western Europe. This work is a new contribution to what is known of the palaeobiodiversity and distribution of large-bodied theropods from the Barremian of the Iberian Peninsula. © 2018, Springer International Publishing AG, part of Springer Nature.
The Spanish Province of Teruel (Aragón) has 13 dinosaur tracksites that have been declared Goods of Cultural Interest (Bienes de Interés Cultural, the highest level of legal protection afforded to Spanish heritage items). The site of El Hoyo in the village of El Castellar lies in the mountain ranges of El Maestrazgo and Sierra de Gúdar ‘Place of Community Interest’ (Lugar de Interés Comunitario), on land forming part of the Natura 2000 Network. It is the only such site in the Camarillas Sandstone Formation (Barremian), and is placed within the Peñagolosa sub-basin (part of the Maestrazgo Basin). Its scientific importance stems from the three theropod trackways it preserves, and from the presence of a macroinvertebrate ichnofabric almost exclusively composed of (abundant) traces of the ichnogenus Taenidium. The site appears to represent a transition zone between a terrestrial and aquatic (non-marine) environment on a floodplain adjacent to low energy rivers. The ichnological study of the site has considerably increased its scientific importance, and has become part of plans aimed at encouraging geotourism.
We describe a new basal iguanodont, Proa valdearinnoensis, from the Lower Cretaceous (lower Albian) Escucha Formation of Teruel Province, Spain. The new taxon is known from abundant cranial and postcranial material belonging to several individuals, and is distinguished by an autapomorphy (predentary comes to a point at its rostral margin, with divergent lateral processes) and a unique combination of characters. Proa fills part of an otherwise lengthy temporal gap (early Aptian-Santonian) in the European fossil record of basal iguanodonts. A preliminary phylogenetic analysis places Proa in a polytomy with Iguanodon bernissartensis and more derived iguanodontians (Hadrosauroidea). Proa is more basal than the Valanginian Hypselospinus and late Barremian-early Aptian Mantellisaurus, suggesting a long ghost lineage leading to Proa.
Delapparentia turolensis Ruiz-Omeñaca, 2011 is the only iguanodont taxon erected in the Barremian of Spain. It is described on the basis of a partial postcranial skeleton discovered in the 1950s near the village of Galve (Teruel Province), within the Camarillas Formation. Recently, new remains from the same individual have been recovered, and these are described here. Furthermore, after first-hand examinations of the holotype, the phylogenetic position of this taxon has been analysed for the first time, and its diagnosis is emended. Delapparentia turolensis is a large-sized, basal iguanodont 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. © 2015, Universidad Complutense de Madrid. All Rights Reserved.
The history of discovery and interpretation of several dinosaurs collected from quarries near the town of Hastings during the latter half of the 19th century is more complicated than it should be. Samuel Husbands Beckles and Charles Dawson collected several large ornithopod skeletons from this area, but just a few bones from these skeletons were subsequently described and interpreted (principally) by Richard Owen and Richard Lydekker. All these specimens merited recognition because they had the potential to contribute to an on-going debate about the anatomical structure and relationships of the iconic Wealden dinosaur Iguanodon. Unfortunately, no detailed description of these important skeletons was published in later years. Furthermore, previously known associations of bones and even provenance information, linked to the specimens that were gradually acquired by the Natural History Museum, are unclear. Confusion may have arisen because Richard Lydekker used the private collector Charles Dawson as a voluntary curatorial assistant. This account documents the past work on the osteology of material that can be attributed to Hypselospinus fittoni. Nearly all such material is described here for the first time, and every effort has been made to re-establish associations between bones as well as provenance information. A skeletal reconstruction of Hypselospinus is attempted on the basis of the hypodigm. Most of the on-going confusion concerning the affinity of this material with either Hy. fittoni or its sympatric contemporary Barilium dawsoni has been resolved. Hypselospinus fittoni (Lydekker, 1889) is rediagnosed on the basis of this new and relatively comprehensive anatomical description, and this animal is compared with known contemporary and closely related taxa. Some recently published accounts claiming to be revisions of the taxonomy of Wealden ‘iguanodonts’, including material belonging to the hypodigm of Hy. fittoni, have failed to adhere to basic taxonomic principles and have caused more confusion than was strictly necessary. The systematic position of Hypselospinus is reassessed cladistically. The cladistic analysis forms the basis for a revised hierarchical classification of derived ornithopods. The consensus topology generated by the systematic analysis has been used to explore the phylogenetic history of these dinosaurs and create an internally consistent classificatory hierarchy (phylogenetic definitions and Linnaean diagnoses are given for critical positions in the topology). This analysis suggests that there is a fundamental split amongst the more derived (clypeodontan) ornithopod ornithischians into the clades Hypsilophodontia and Iguanodontia. There is evidence for anatomical parallelism and convergence (homoplasy) particularly between large-bodied representatives of both clades. Hypselospinus is one of the earliest known styracosternan iguanodontians and displays anatomical characteristics that presage the evolution of the extraordinarily abundant and diverse hadrosaurs of the latest Cretaceous (Campanian−Maastrichtian). These observations cast fresh light on the phylogeny, classification, diversity, and biology of derived ornithopods. There is little doubt that Hy. fittoni could have been understood far better more than a century ago. That this statement is undoubtedly true is reflected in the century of doubt and confusion that has surrounded this taxon and its original incarnation as Iguanodon fittoni. © 2014 The Linnean Society of London
A well-preserved macroflora and rich palynological assemblages corresponding to the Camarillas Formation (early-middle Barremian) in the San Cristo´bal and Galve Mine sites from the Galve sub-basin in northeastern Spain are presented here. These remains represent the first fossil plant evidence from these deposits. Within plant macroremains, the cheirolepidiacean Pseudofrenelopsis aff. varians (Fontaine) Watson has been found. The palynological assemblage yielded well-preserved spores and pollen grains, mainly dominated by the genus Classopollis. Spores are also abundantly represented by schizaeacean spores (Cicatricosisporites and Plicatella). This spore assemblage supports an early-middle Barremian age for these localities. It is noteworthy that small basal angiosperm pollen grains of the genera Crassipollis and Retimonocolpites, together with other indeterminate grains, have been reported here. This flora constitutes the primary food producer for dinosaur at that time, and thus the information of the flora is important for the understanding of the ecological background for the dinosaur evolution during the Early Cretaceous.
Albert F. de Lapparent (1905-1975), the scion of a family of famous French geologists, was a dinosaur palaeontologist. He explored many territories in Europe, Saharan Africa and Asia in search of fossils. The studies he undertook in Spain, which resulted in a dozen publications between 1955 and 1969, are an important part of his research on dinosaurs. Lapparent et al. discovered about thirty dinosaur localities, mostly of Cretaceous age, in several Spanish provinces, including Albacete, Castellón, Cuenca, Soria, Teruel and Valencia in the Iberian Range, and Lleida (or Lérida) in the Pyrenean region. In 1958, Lapparent published the discovery of dinosaur eggs in the Tremp Basin (Lleida), the first ones found in the Iberian Peninsula. His 1960 work on the dinosaurs of Galve (Teruel) was the first monograph on the subject published in Spain. In 1965, Lapparent was also the first to publish the discovery of dinosaur footprints in Spain, more specifically in the province of Valencia.
An isolated, fully articulated hindlimb of a basal iguanodont from the Spanish Las Hoyas Lagerstätte is described. It probably belonged to a juvenile or subadult individual. Despite some slight differences, anatomical features, as well as the late Barremian age of this specimen, would suggest that it belongs to Mantellisaurus atherfieldensis. The exquisite preservation of this specimen provides information on the foot anatomy of basal iguanodonts. This is the first report of a non-theropod dinosaur from Las Hoyas. From a palaeoecological point of view, this discovery indicates that potential prey of the carcharodontosaurian theropod Concavenator were present at Las Hoyas, thus complementing our knowledge of the trophic structure of this Early Cretaceous palaeocommunity.
A partially articulated postcranial skeleton of a small ornithischian dinosaur, Gideonmantellia amosanjuanae nov. gen. et sp., from the Early Cretaceous of Galve (Teruel province, Spain) is described. It was recovered in an outcrop of fluvial red clays from the Camarillas Formation, which is Barremian in age. This partial skeleton is recognised as a new ornithopod taxon by the following autapomorphies: (1) postacetabular process of the ilium with a brevis shelf that is noticeably medially expanded in its cranial part but narrow and horizontal in its caudal part; (2) rod-like prepubic process with its anterior end twisted and expanded; and (3) L-shaped first chevron. Our phylogenetic analysis indicates that Gideonmantellia represents a basal ornithopod taxon more derived than Orodromeus, the “Asian clade” (which includes Haya and others) and Hypsilophodon.
The Las Cerradicas site (Tithonian-Berriasian), Teruel, Spain, preserves at least seventeen dinosaur trackways, some of them formerly attributed to quadrupedal ornithopods, sauropods and theropods. The exposure of new track evidence allows a more detailed interpretation of the controversial tridactyl trackways as well as the modes of locomotion and taxonomic affinities of the trackmakers.
Detailed stratigraphic analysis reveals four different levels where footprints have been preserved in different modes. Within the tridactyl trackways, manus tracks are mainly present in a specific horizon relative to surface tracks. The presence of manus tracks is interpreted as evidence of an ornithopod trackmaker. Cross-sections produced from photogrammetric digital models show different depths of the pes and manus, suggesting covariance in loading between the forelimbs and the hindlimbs.
Several features (digital pads, length/width ratio, claw marks) of some ornithopod pes tracks from Las Cerradicas are reminiscent of theropod pedal morphology. This morphological convergence, combined with the shallow nature of the manus tracks, which reduces preservation potential, opens a new window into the interpretation of these tridactyl tracks. Thus, trackmaker assignations during the Jurassic-Cretaceous interval of purported theropod trackways may potentially represent ornithopods. Moreover, the Las Cerradicas trackways are further evidence for quadrupedalism among some basal small- to medium-sized ornithopods from this time interval.
A new ornithopod from the Lower Cretaceous Yellow Cat Member of the Cedar Mountain Formation in eastern Utah is described. This specimen is represented by a well-preserved left ilium, preac-etabular process of the right ilium, right tibia, right metatarsal III, fused sacrum, ribs, and ossified tendons. The ilium overall resembles that of the iguanodontid Camptosaurus, which we interpret as the plesiomorphic condition, but it has the lateral process ("an-titrochanter") that characterizes hadrosaurs. The plesiomorphic character of the elements suggests a recent departure from iguanodontids, whereas the synapomorphic lateral process suggests that this taxon represents a basal hadrosaur.
A dentary fragment that preserves several teeth in situ of an ornithopod dinosaur from the Lower
. Cretaceous of Salas de los Infantes (Burgos, Spain) is described. The general aspect and the conservation
of the rock associated with the fossil suggest that it would come from the Pin ilia de los Moros Formation
(upper Hauterivian-lower Barremian). The material takes part, together with other fossils of dinosaurs and
crocodilians, of a collection gathered at the end of the 7 960's and deposited nowadays in the Institut far
Geowissenschaften of the University of Tabingen (Germany). The dentary teeth exhibit a distal primary
ridge and a mesial secondary ridge, as typically in basal iguanodontoids. Nevertheless, some teeth show a
single subcentral carina and lack subSidiary ridges, as in hadrosaurids. Unlike hadrosaurids, however, the
Salas specimen has probably one functional tooth and one replacement crown per dentary tooth position,
retaining the plesiomorphic state present in basal iguanodontoids. Due to the fragmentary nature of the
material, it is proviSionally assigned to Iguanodontoidea indet.
,Key words: Ornithopoda, Iguanodontoidea, Lower Cretaceous, Burgos, Spain.
Craspedodon lonzeensis DOLLO, 1883 is based on three teeth discovered in the Lonzée Member (?Coniacian-Santonian, Upper Cretaceous) in the surroundings of the village of Lonzée (Namur Province, Belgium). Previous authors identified Craspedodon as an iguanodontian dinosaur. We rather propose that these fossils belong to a neoceratopsian dinosaur, because of the following characters: the enamelled side of the crown bears deep indentations and a prominent basal cingulum, the opposite side of the crown is very convex vertically and bulbous in mesial view, and secondary ridges start from the apical edge but end prior to the base of the crown. Within Neoceratopsia, it is suggested that Craspedodon has more affinities with Ceratopsoidea (sensu You & DODSON, 2003) than with Protoceratopsidae. It is the first time that ceratopsian dinosaurs are described in Europe. Neoceratopsians probably migrated from Asia into Europe during the Aptian-Albian, when intermittent land bridges were established across the Turgai Straits. This implies a relatively long ghost lineage for neoceratopsians in Europe, of more than nine million years, between their migration towards Europe and their proposed presence in the Lonzée Member.
The right dentary of a new hadrosauroid dinosaur, Penelopognathus weishampeli, has been discovered in the Bayan Gobi Formation (Albian, Lower Cretaceous) of Inner Mongolia (P.R. China). This new taxon is characterised by its elongated, straight dental ramus, whose lateral side is pierced by about 20 irregularly distributed foramina. Its dentary teeth appear more primitive than those of Probactrosaurus, but more advanced than those of Altirhinus, both also from the Lower Cretaceous of the Gobi area. Non-hadrosaurid Hadrosauroidea were already well diversified in eastern Asia by Early Cretaceous time, suggesting an Asian origin for the hadrosauroid clade. To cite this article: P. Godefroit et al., C. R. Palevol 4 (2005).
A new hadrosauriform dinosaur, Jintasaurus meniscus gen. et sp. nov., is reported from the Lower Cretaceous Xinminpu Group of the Yujingzi Basin, Jiuquan area, Gansu Province, northwestern China. It is represented by an articulated posterior portion of the skull and is unique in having an extremely long, pendant and crescentic paroccipital process with its ventral tip projecting far beyond the ventral level of the occipital condyle. Phylogenetic analysis recovers Jintasaurus as the sister-taxon to Hadrosauroidea, more derived than other Early Cretaceous hadrosauriforms and Protohadros from the early Late Cretaceous of North America. This discovery adds one more close relative to Hadrosauroidea in Asia and supports an Asian origin for this group.La présence est signalée d'un nouveau dinosaure hadrosauriforme, Jintasaurus meniscus gen. et sp. nov., dans le Groupe de Xinminpu du Crétacé inférieur du bassin de Yujingzi, dans la région de Jiuquan de la province de Gansu (nord-ouest de la Chine). Il est représenté par une portion postérieure articulée du crâne et se distingue par la présence d'un processus paroccipital pendant extrêmement long en forme de croissant, dont la pointe ventrale est projetée bien au-delà de niveau ventral du condyle occipital. L'analyse phylogénétique révèle que Jintasaurus est le taxon frère d'Hadrosauroidea, plus dérivé que d'autres hadrosauriformes du Crétacé inférieur et que Protohadros, du début du Crétacé tardif de l'Amérique du Nord. Cette découverte vient ajouter un nouveau proche parent des Hadrosauroidea en Asie et appuie la thèse de l'origine asiatique de ce groupe.
Eolambia caroljonesa was described as a basal, crestless lambeo-saurine hadrosaurid on the basis of multiple disarticulated skeletons from the uppermost Cedar Mountain Formation (Albian–Cenomanian boundary, 98.39 0.07 Ma) of eastern Utah (Cifelli et al., 1997; Kirk-land, 1998). The occurrence of a lambeosaurine at the Early–Late Cre-taceous transition is significant as it indicates Early Cretaceous origins of both Hadrosauridae and other derived iguanodontians (e.g., Bactro-saurus, Telmatosaurus, Protohadros), for which there is no additional evidence (Weishampel et al., 1993; Godefroit et al., 1998; Head, 1998). The purpose of this analysis is to test the proposed phylogenetic status of Eolambia within derived iguanodontians (Iguanodon and all more derived taxa), based on reinterpretation of the character states of the taxon as well as description of additional remains. The hypodigm of Eolambia consists of specimens that are housed in the College of Eastern Utah Museum (CEUM), Price (holotype and paratype), and the Oklahoma Museum of Natural History (OMNH), Norman (paratype). CEUM specimens consist of two disarticulated, par-tial skeletons from two localities (Kirkland, 1998). This study empha-sizes OMNH specimens in phylogenetic analysis however, because: (1) the majority of lambeosaurine synapomorphies reported for Eolambia are based on these specimens; (2) OMNH materials represent a greater proportion of the skeleton, including the skull, than reported CEUM specimens; and (3) only OMNH Eolambia localities have been geo-graphically and stratigraphically correlated with each other and a radio-metric datum in the literature (Cifelli et al., 1999). Oklahoma Museum specimens represent at least six individuals from five localities. The majority of elements in this analysis are from OMNH v824 (possibly a single individual) and OMNH v237, a locality includ-ing at least two individuals as indicated by two different scapular lengths (OMNH 4219 26 cm complete: OMNH 4221 33 cm in-complete). A right surangular (OMNH 4218) is described from OMNH v237 (not OMNH v824 Kirkland, 1998:287), and a sacrum (OMNH 27749) from OMNH v696 (Kirkland, 1998; Cifelli et al., 1999) is also incorporated in this study. DESCRIPTION Diagnostic cranial elements of Eolambia include a right premaxilla, right surangular, and basisphenoid. The majority of lambeosaurine cra-nial synapomorphies were reported from the premaxilla, but the sur-angular and basisphenoid have not been previously described. The pre-maxilla (OMNH 28919) possesses prominent premaxillary foramina that communicate through the dorsal, ventral, and anteromedial surfaces of the element. Ventrally, (Fig. 1B) two foramina are located toward the oral margin of the premaxilla, more anteriorly positioned than in other iguanodontians. A small channel extends between these foramina and the interpremaxillary articular surface. The foramina exit the pre-maxilla dorsally as an elongate fissure and secondary channel, posterior to the base of the ascending process. Dorsally, (Fig. 1A) a shallow embayment is present on the lateral surface of the premaxillary ascend-ing process, dorsal to the narial foramen. The embayment receives an anterior projection of the nasals in other iguanodontians (Norman, 1986; Horner, 1992), indicating that the nasals formed the dorsolateral margins of the external nares in Eolambia. Medially (Fig. 1C), a longitudinal groove is present on the ventral and medial surfaces of the premaxilla, posterior to the beak. In ventral view, the groove is deep and antero-medially angled. The groove receives a portion of the maxillary rostro-dorsal process in other derived iguanodontians (e.g., Horner, 1992). The surangular (OMNH 04218) is elongate, with a strongly inflected retroarticular process in lateral view (Fig. 1E). A prominent surangular foramen is present at the base of the mandibular glenoid, and a smaller accessory foramen occurs anterodorsal to the surangular foramen. In dorsal view (Fig. 1D) the glenoid shelf is transversely expanded with an upturned lateral margin. The medial margin of the shelf is not pre-served. In ventral view (Fig. 1F), the articular surface for the angular consists of a highly interdigitated, medially expanded shelf. The ori-entation of the articular surface for the angular (Fig. 1E, F) indicates that the angular was positioned ventrally as in Protohadros and more basal iguanodontians (Weishampel et al., 1993; Head, 1998). The basisphenoid (OMNH 28920) is nearly complete, missing only the left basipterygoid process. In ventral view, it is roughly triangular with a prominent, anteriorly projected parasphenoid process (Fig. 1G). Posteriorly, the contributions of the basisphenoid to the basal tuberae consist of widely spaced and ventrally deflected hemispherical process-es whose posteroventral margins compose the articular surfaces for the basioccipital. In lateral view (Fig. 1H), the basipterygoid processes de-scend from the long axis of the element at an angle of approximately 32. This is a shallower angle than seen in lambeosaurines and most hadrosaurines (Weishampel and Horner, 1990). The vidian canal is pre-sent along the lateral surface of the basisphenoid, extending from just anterodorsal to the divergence of the basipterygoid processes to incom-plete dorsal margin of the element. Diagnostic postcranial elements include a right ilium and incomplete right femur. The ilium of Eolambia (OMNH 04213) is dorsoventrally shallow in lateral view (Fig. 2B), with an elongate, ventrally deflected prepubic process. The dorsal margin is expanded and rugose. It is lat-erally reflected from the posterior extent of the prepubic process to the posterior margin of the element (Fig. 2B, C) for the attachment for the hindlimb adductor musculature, as in other iguanodontians (e.g., Nor-man, 1986). Ventrally, the pubic peduncle is elongate and anteriorly angled. The acetabulum is extremely large for the size of the ilium, larger than the condition reported for any ontogenetic stage in other iguanodontians (e.g., ''Vectisaurus'' Norman, 1990; Hypacrosaurus Horner and Currie, 1994). The ischiatic peduncle is similar to ''hadro-sauroid'' (sensu Godefroit et al., 1998) grade iguanodontians, in that it is more poorly defined than seen in Iguanodon, Ouranosaurus, or Al-tirhinus (Taquet, 1976; Norman, 1986, 1998). The peduncle appears to extend to the posterior margin of the ilium. The ilium of Eolambia is unique in lacking a distinct postpubic (postacetabular) region behind the ischiatic peduncle. In Camptosau-rus, Iguanodon, Ouranosaurus, and Altirhinus, the postpubic region is continuous with the main body of the ilium, with an anteroventrally angled posterior margin. In more derived taxa (Gilmoreosaurus, Bac-trosaurus, Hadrosaurinae, Lambeosaurinae), the postpubic region con-sists of a distinct, separate process that is free of the reflected dorsal margin of the ilium. The femur of Eolambia (OMNH 04202) is represented by a specimen that lacks the proximal extremity. Distally, the condyles are not as an-teroposteriorly expanded as seen in other derived iguanodontians (e.g., Bactrosaurus, Gilmoreosaurus, Telmatosaurus, Hadrosaurinae, Lam-beosaurinae), and are separated by a wide anterior intercondylar groove
A new iguanodontid,Jinzhousaurus yangi gen. et sp. nov., is erected based on the cranial and dental morphology of a specimen from the Yixian Formation of western
Liaoning. Although a few primitive characteristics remain,Jinzhousaurus yangi display a number of characteristics similar to those seen in derived iguanodontids. Other interesting characteristics include
the absence of antorbital fenestra and the frontal excluded from the participation in orbit, which are closer to the condition
in hadrosaurids. The unusual combination of the characteristics provides important data for assessing morphological evolution
toward hadrosaurs. The new discovery also represents the first reported large-sized dinosaur from Jehol fauna in western Liaoning,
and increases the diversity of this famous fauna. Furthermore, the discovery of a derived iguanodontid from the Yixian Formation
provides further evidence supporting a Cretaceous age of the Jehol fauna, which is consistent with an isotopic age.
Vectisaurus valdensis is considered to be the imperfectly preserved remains of juvenile Iguanodon. Based on juvenile material of Iguanodon recovered from Nehden (Federal Republic of Germany), Vectisaurus is most probably referrable to I. atherfieldensis. Ornithopod relationships have been evaluated by reference to the detailed recent systematic reviews of the Ornithischia. Results from this study suggest that the family Iguanodontidae is valid, if more restricted than previously argued; that Tenontosaurus tilletti is more closely related to hypsilophodontians than iguanodontians; and, that Probactrosaurus gobiensis is the sister-taxon of the Hadrosauridae. A review cladogram of advanced ornithopod dinosaurs is proposed. -Author
El yacimiento de “Zorralbo” en el municipio de Golmayo (Soria, España), perteneciente al Cretácico Inferior(Hauteriviense superior/Barremiense inferior), ha proporcionado un conjunto faunístico formado por los restos de cinco taxones de dinosaurios (Ornithopoda, Sauropoda, Theropoda y Thyreophora), una tortuga Criptodira y un cocodrilo “Mesosuquio”, fauna que nos ayuda a comprender la composición de los ecosistemas europeos en el Cretácico Inferior y que constituye una aportación importante al conocimiento de los vertebrados del Cretácico Inferior de España.
New material and a restudy of old suggests that Muttaburrasaurus is not an iguanodontid ornithopod, but probably diverged from the iguanodontian-hadrosaur lineage prior to the divergence of taxa such as Dryosaurus and Tenontosaurus. The type skull differs from a second, older skull from the Allaru Mudstone in ways that suggest a trend toward the evolution of a continuous more-or-less planar sheet of enamel along the labial face of the maxillary dentition. Teeth from Lightning Ridge (Griman Creek Fm.) may pertain to a more plesiomorphic species of Muttaburrasaurus.
The taxonomic affinities of species assigned to Camptosaurus are reassessed in light of firsthand examination of the relevant specimens and a new phylogenetic analysis, the first to incorporate all putative species of Camptosaurus. "Camptosaurus" valdensis is found to be an indeterminate dryosaurid. The species C. prestwichii, C. aphanoecetes, and C. depressus differ in several important details from the type species, C. dispar, and are assigned to different genera as Cumnoria prestwichii, Uteodon aphanoecetes gen. et comb. nov., and Osmakasaurus depressus gen. et comb. nov. The recent assignment of O. depressus to the genus Planicoxa is considered unjustified.
The type material of the Cretaceous ornithopod Iguanodon orientalis Rozhdestvensky, 1952 is redescribed. The characters which were originally used to establish a new species are shown to be either incorrect or indistinguishable from Iguanodon bernissartensis Boulenger, 1881. Additional material, previously unrecognized, further confirms the similarity of I. orientalis to I. bernissartensis. It is proposed that I. orientalis should be relegated in synonymy as a junior subjective synonym of I. bernissartensis Boulenger, 1881. The identification of the Barremian species I. bernissartensis in Asia indicates an unusually wide geographic spread for this species, and provides a potential biostratigraphic indicator for beds in Mongolia which had been previously dated variously between the Cenomanian and Maastrichtian stages.
Part of the thoracal vertebral column of Iguanodon cf. fittoni LYDEKKER 1889, from the Lower Cretaceous Tera-Beds of Salas de los Infantes provides the first record of this rare and little known euornithopod dinosaur outside Great Britain. The dinosaur-bearing strata of Salas de los Infantes can possibly be correlated with the Waldhurst Clay of the English Wealden.
After more than ten years of Thai-French research, the Thai dinosaur record, from the continental rocks of the Khorat Plateau, is, to date, the best in Southeast Asia. The oldest evidence consists of footprints of small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblage hitherto found in Thailand comes from the Late Jurassic Sao Khua Formation; it is dominated by sauropods, but also includes various theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation.
Fusion of caudal vertebrae in the sauropod dinosaurs Apatosaurus, Diplodocus, and Camarasaurus is explained as the result of ossification of ligaments spanning consecutive centra. The ossification does not involve the intervertebral space or the annulus fibrosus of the disc and therefore represents true bridging. This is verified by not only the gross external appearance, but also by the use of CAT scans and longitudinal section of a fused pair of Diplodocus caudal vertebrae. Fusion of caudal vertebrae in Camarasaurus is reported here for the first time. It is concluded that the fusion is the result of the physiological phenomenon called diffuse idiopathic skeletal hyperostosis (DISH) and therefore is not a pathological response or due to a physical injury. Various proposed hypotheses to explain the function of the fused caudals, such as defense and postural support, are considered untenable. Fusion of caudal vertebrae probably aided in keeping the tail elevated and undoubtedly served a functional role, though the specific nature of that function is presently unknown. Survey of North American specimens indicates that fusion of caudal vertebrae occurs in 50% of the individuals of Apatosaurus and Diplodocus in which the requisite portion of the tail is preserved, whereas this figure for Camarasaurus is about 25%. For this reason it is suggested that fusion of caudal vertebrae may be a sexually dimorphic feature.
The first species from the United States that can clearly be referred to the European genus Iguanodon is described from the Lakota Formation of South Dakota. Consisting of virtually the entire skull and two vertebrae, I. lakotaensis (sp. nov.) represents the most primitive of Iguanodon species. Presence of Iguanodon from the Barremian (Lower Cretaceous) Lakota Formation confirms the suggestion that there was a close connection between the North American and Eurasian continental blocks during or immediately before this time.
The present communication is divided into four sections—the first giving an account of Iguanodont remains obtained from the Wadhurst Clay near Hastings subsequently to the writer's previous paper on this group; the second devoted to the description of a metatarsus of a Megalosaurian from the same deposits; the third recording some vertebræ of a Sauropterygian from the Purbeck of the Isle of Portland; while the fourth gives a description of an associated series of remains of a Pliosaur from the Oxford Clay near Peterborough.
I. The Iguanodonts of the Wadhurst Clay.
Two years ago I brought under the ndice of the Society certain remains of large Iguanodonts collected by Mr. C. Dawson, F.G.S., from the Wadhurst Clay (Lower Wealden) in the neighbourhood of Hastings, and now preserved in the British Museum. Among these a left ilium and some associated vertebræ presented such differences from the corresponding bones of Iguanodon Mantelli and I. bernissartensis, that I felt justified in regarding them as the types of a distinct species, for which the name I. Dawsoni was proposed. I was careful at that time to mention that these specimens only were taken as the types, and it is fortunate that this was done, since it now appears that the sacrum and ischium which, in the absence of any evidence to the contrary, were referred lo the same species, belong to a distinct form.
Since the publication of that paper Mr. Dawson has assiduously continued his collecting in the quarries of the Wadhurst Clay
Introductory.—The primary object of this communication is to bring to the notice of the Society numerous remains of an apparently new Iguanodont Reptile obtained by Mr. C. Dawson, F.G.S., of St. Leonards, from the Wadhurst Clay (one of the beds of the Hastings Sand, or lower division of the Wealden), and recently acquired by the British Museum; and also a maxilla from the Wealden of the Isle of Wight, apparently referable to Ornithopsis. Having, however, recently examined the whole of the collection of Dinosaurian remains preserved in the Museum, in the course of the preparation of the first part of the forthcoming ‘Catalogue of Fossil Reptilia’ of the collection, I have also made certain observations regarding other members of the order, which may be conveniently recorded at the same time.
Iguanodonts.—Commencing with the Iguanodonts, I may first of all observe that I fully concur in the view which M. Dollo informs me he now takes as to the specific identity of Iguanodon bernissartensis and I. Seelyi; and, although the original description is very meagre and unaccompanied by a figure, I think we ought to adopt the former and earlier name for the species which has been so well described by the Belgian naturalist. The British Museum possesses a considerable series of the remains of this species, many of which were referred by Sir R. Owen to Cetiosaurus and Pelorosaurus, while others have been described under the name of Iguanodon Mantelli.
In addition to the two Wealden species of Iguanodon (I.
On the 13th of October, 1871, I found, weathered out, lying on the cliff-foot, 300 yards east of the flagstaff near Brixton Chine, Isle of Wight, the fossil remains now submitted to the Society. The extreme autumnal heat had much cracked the surface of the clay in which the bones had been entombed; and these also were shattered into numberless small fragments, most of which could not be joined, so that parts of six vertebræ and of a large flat bone, which I regard as an ilium, were all that could be recovered. Since then I have several times revisited the spot in the hope of finding other portions of the skeleton, but fruitlessly; and as the cliff-foot is now wasted back to such a distance as to make the recovery of it most unlikely, the time has come when, without incurring the charge of undue haste, I may bring under the notice of the Society these evidences of what I venture to think will be received as a new Dinosaurian genus.
A ponderously constructed ornithischian dinosaur, Lurdusaurus arenatus, nov.g., nov.sp., from the Aptian of Niger resembles extinct giant ground sloths in general body form. Details of its skeletal anatomy indicate a close affinity to European iguanodontids of Early Cretaceous age.
The remains of an ornithopod dinosaur from the Upper Barremian (Lower Cretaceous) of Auxerre (Burgundy, France) are described. They consist of several vertebrae and a fragmentary scapula. Despite obvious morphological and dimensional affinities with the species Iguanodon bernissartensis, the state of the specimen does not allow any identification more precise than Iguanodontia indet. Reappraisal of the French Upper Barremian record of medium and large-sized ornithopods reveals that no specimen can be definitely determined to the specific level.
Ornithischian dinosaur remains from the Maortu site in Alashan' occur in three bone bearing horizons; those in the lower two are of advanced iguanodont affinity and those in the upper are very primitive hadrosaurs. These are the first beds in which iguanodonts have been found so closely associated with hadrosaurs. The uppermost bed is well developed at Iren-Nor, not far from Maortu, from which the primitive hadrosaur Bactrosaurus johnsoni was described. Other remains from Asia described as iguanodonts, upon re-diagnosis turn out to be sauropods. The iguanodont remains from Maortu are assigned to a new genus Probactrosaurus, on the basis of hadrosaur-like characters of dentition and limbs and other distinctive characters that show no particular trend. Two species are described, P. gobiensis from the lowermost horizon, and P. alashanicus from the next superjacent horizon. P. alashanicus is more nearly like the hadrosaur B. johnsoni in most respects, and the sequence P. gobiensis - P. alashanicus - B. johnsoni may indicate stages in a rapid transition from an iguanodont to a hadrosaurian level of organization. On the basis of the morphological affinities of the dinosaur remains, the uppermost bed at Maortu is assigned a Cenomanian (earliest Upper Cretaceous) age, while the two lower beds may be dated to the Aptian-Albian (end of the Lower Cretaceous). — N.H. Hotton III.
Ostéologie de Zalmoxes shqiperorum (Dinosauria, Ornithopoda), d'après de nouveaux spécimens du Crétacé supérieur de Năălaţţ-Vad (Roumanie). Năălaţţ-Vad est un nouveau site fossilifere découvert en 2002 dans la Formation de Săănpetru (Maastrichtien, Crétacé supérieur) du bassin de Haţţeg (Transylvanie, Roumanie). Ce site a notamment livré le squelette le plus complet à ce jour pouvant être attribué au dinosaure ornithopode Zalmoxes shqiperorum Weishampel, Jianu, Cziki & Norman, 2003, mais également des ossements isolés appartenant à des individus juvéniles et adultes. Ce matériel apporte de nouvelles informations sur l'anatomie de Z. shqiperorum, mais également sur la variabilité inter- et intraspécifique au sein même du genre Zalmoxes. Zalmoxes robustus (Nopsca, 1902) et Z. shqiperorum étaient apparemment des espèces sympatriques en Transylvanie au Crétacé supérieur. La coexistence dans une même localité de deux espèces proches n'est pas un cas isolé chez les dinosaures ornithopodes.
In the present communication I call attention to a Reptilian vertebra which does not appear to have received the notice it deserves, and also give a preliminary diagnosis of certain forms which I hope to describe more fully later on.
Abstract A new hadrosauroid dinosaur, Shuangmiaosaurus gilmorei gen. et sp. nov., is described based on a complete left maxilla with articulated premaxilla and lacrimal fragments, and a complete left dentary from the mid-Cretaceous Sunjiawan Formation of Beipiao, Liaoning, northeastern China. Cladistic analysis shows that Shuangmiaosaurus is a basal hadrosauroid, and comprises the sister taxon to Hadrosauridae. In both Shuangmiaosaurus and Hadrosauridae, the maxilla-jugal suture is butt-jointed, rather than finger-in-recess articulation as in other basal hadrosauroids. However, Shuangmiaosaurus does not possess such hadrosaurid synapomorphies as the diamond-shaped maxillary crowns with reduced primary ridges and reduced marginal denticles.
This paper discusses the lithostratigraphy of the Xinminbao Group in the Mazongshan area of Gansu Province, northwestern China, and the correlation of its biota. The Xinminbao Group was deposited in a fluviolacustrine setting in Mesozoic graben basins under a semi-arid, subtropical climate. The fossil sites concentrated in the lower part of the group have yielded dinosaurs, mammals and other vertebrates that are comparable to the Aptian–Albian vertebrate assemblages that have been found in Mongolia and Siberia. Based on their invertebrate and vertebrate fossils, sediments of the lower part of the Xinminbao Group are considered to be Late Barremian–Aptian in age, although the middle and upper parts could be as young as Albian. The megafossil plants and conchostracans are comparable to those of the Yixian and Jiufuotang Formations in eastern China (Barremian–Aptian). The palynoflora is also comparable to that of the upper Lower Cretaceous elsewhere in northern China, although the presence of two angiosperm taxa, Asteropollis and Tricolpites, suggests that the main fossil sites are Albian. These biostratigraphic data for the Mazongshan area provide a new temporal calibration for the terrestrial biotas of the Lower Cretaceous of central Asia, where most of the known dinosaur-bearing sediments lack precise palynological, radiometric and magnetostratigraphic dating.
Criteria for designating dinosaur genera are inconsistent; some very similar species are highly split at the generic level, other anatomically disparate species are united at the same rank. Since the mid-1800s the classic genus Iguanodon has become a taxonomic grab-bag containing species spanning most of the Early Cretaceous of the northern hemisphere. Recently the genus was radically redesignated when the type was shifted from nondiagnostic English Valanginian teeth to a complete skull and skeleton of the heavily built, semi-quadrupedal I. bernissartensis from much younger Belgian sediments, even though the latter is very different in form from the gracile skeletal remains described by Mantell. Currently, iguanodont remains from Europe are usually assigned to either robust I. bernissartensis or gracile I. atherfieldensis, regardless of location or stage. A stratigraphic analysis is combined with a character census that shows the European iguanodonts are markedly more morphologically divergent than other dinosaur genera, and some appear phylogenetically more derived than others. Two new genera and a new species have been or are named for the gracile iguanodonts of the Wealden Supergroup; strongly bipedal Mantellisaurus atherfieldensis Paul (2006. Turning the old into the new: a separate genus for the gracile iguanodont from the Wealden of England. In: Carpenter, K. (Ed.), Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Indiana University Press, Bloomington, pp. 69–77) (holotype BMNH R5764) which possesses a camptosaur-like ilial shape, and the long snouted, long bodied, small hipped, semi-bipedal Dollodon bampingi gen. nov. sp. nov. (holotype IRSNB 1551) which has a shallow ilium. Insufficiently diagnostic I. hoggii is removed from the earlier Camptosaurus. Poorly described I. dawsoni, I. fittoni and I. hollingtoniensis are removed from the much later and more derived Iguanodon and considered Ornithopoda incertae sedis pending redescription. The synonymy of I. fittoni and I. hollingtoniensis has not been confirmed. A set of remains of similar age to I. fittoni and I. hollingtoniensis appear to combine a specialized, elongate dentary with massive arms: it either belongs to one of the contemporary taxa, or is a new, unnamed taxon. There has recently been a tendency to consider iguanodonts spatially remote from I. bernissartensis to be members of or very similar to the type species, but reanalysis finds that I. orientalis is not a junior synonym of I. bernissartensis and is a nomen dubium, and that basal I. lakotaensis is not a member of Iguanodon and accordingly is assigned the new genus Dakotadon gen. nov. (holotype SDSM 8656). Dakotadon is probably basal to Iguanodon and not an iguanodontoid. The higher taxonomy of iguanodontoids is confused due to phylogenetic problems, and inconsistent definitions of the Iguanodontidae (which as currently defined appears to be limited to Iguanodon) and Hadrosauroidea. Mantellisaurus and especially Dollodon, for instance, are probably more derived than Iguanodon: they may be hadrosauroids depending on which phylogenetic definition of the term is preferred.