scholarly journals Additional sauropod dinosaur material from the Callovian Oxford Clay Formation, Peterborough, UK: evidence for higher sauropod diversity

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6404
Author(s):  
Femke M. Holwerda ◽  
Mark Evans ◽  
Jeff J. Liston
Keyword(s):  
Transverse Process ◽  
Neural Spine ◽  
Caudal Vertebra ◽  
High Complexity ◽  
Neural Arch ◽  
Faunal Assemblage ◽  
Diagnostic Features ◽  
Nutrient Foramina ◽  
Tentative Evidence ◽  
Clay Formation

Four isolated sauropod axial elements from the Oxford Clay Formation (Callovian, Middle Jurassic) of Peterborough, UK, are described. Two associated posterior dorsal vertebrae show a dorsoventrally elongated centrum and short neural arch, and nutrient or pneumatic foramina, most likely belonging to a non-neosauropod eusauropod, but showing ambiguous non-neosauropod eusauropod and neosauropod affinities. An isolated anterior caudal vertebra displays a ventral keel, a ‘shoulder’ indicating a wing-like transverse process, along with a possible prespinal lamina. This, together with an overall high complexity of the anterior caudal transverse process (ACTP) complex, indicates that this caudal could have belonged to a neosauropod. A second isolated middle-posterior caudal vertebra also shows some diagnostic features, despite the neural spine and neural arch not being preserved and the neurocentral sutures being unfused. The positioning of the neurocentral sutures on the anterior one third of the centrum indicates a middle caudal position, and the presence of faint ventrolateral crests, as well as a rhomboid anterior articulation surface, suggest neosauropod affinities. The presence of possible nutrient foramina are only tentative evidence of a neosauropod origin, as they are also found in Late Jurassic non-neosauropod eusauropods. As the caudals from the two other known sauropods from the Peterborough Oxford Clay, Cetiosauriscus stewarti and an indeterminate non-neosauropod eusauropod, do not show the features seen on either of the new elements described, both isolated caudals indicate a higher sauropod species diversity in the faunal assemblage than previously recognised. An exploratory phylogenetic analysis using characters from all four isolated elements supports a basal neosauropod placement for the anterior caudal, and a diplodocid origin for the middle caudal. The dorsal vertebrae are an unstable OTU, and therefore remain part of an indeterminate eusauropod of uncertain affinities. Together with Cetiosauriscus, and other material assigned to different sauropod groups, this study indicates the presence of a higher sauropod biodiversity in the Oxford Clay Formation than previously recognised. This study shows that it is still beneficial to examine isolated elements, as these may be indicators for higher species richness in deposits that are otherwise poor in terrestrial fauna.

New anomalies and pathologies in the caudal region of the lizard’s axial skeleton

2021 ◽  
Vol 325 (4) ◽  
pp. 447-456
Author(s):  
D.A. Gordeev ◽  
D.V. Korost ◽  
N.B. Ananjeva
Keyword(s):  
Soft Tissues ◽  
Transverse Process ◽  
Axial Skeleton ◽  
Neural Spine ◽  
Complex Nature ◽  
Caudal Vertebra ◽  
X Ray ◽  
Complete Ablation ◽  
Lacerta Agilis ◽  
The Right

Currently, more than 58 skeletal anomalies and pathologies are known in the recent Squamata reptiles. In this paper, eight pathologies of a complex nature are described in Agamidae and Lacertidae: Paralaudakia caucasia (Eichwald, 1831) and Lacerta agilis Linnaeus, 1758. Description of tail pathologies was carried out based on the analysis of X-ray images and on the results of computer microtomography. In the specimen of P. caucasia (ЗИН 19116.1) complete ablation of the caudal vertebra was revealed, which provoked the detachment of chevron and the proliferation of soft tissues. In some Agamidae, after pseudoautotomy, partial ablation of the caudal vertebra occurs to promote wound healing. Complete ablation of the distal caudal vertebra has not been previously reported in literature. In females of L. agilis, deformation of the right transverse process of the vertebra with “false bifurcation” without the formation of a cartilaginous tube (VOLSU 98.2), scoliosis, hematoma and callus on the cartilaginous tube were noted, as well as the absence of an autotomy plane in the postpygal vertebra (ZIN 31549). An unusual pathology in L. agilis (ZIN 31549) is the absence of an autotomy plane in the postpigal vertebra and of its anterior neural spine. The loss of the plane of autotomy during ontogeny is characteristic of some Iguanidae, but it has not been previously noted in Lacertidae. The described cases of anomalies expand the spectrum of known pathologies in reptiles.

scholarly journals First rebbachisaurid sauropod dinosaur from Asia

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246620
Author(s):  
Alexander Averianov ◽  
Hans-Dieter Sues
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Upper Cretaceous ◽  
Neural Spine ◽  
Lateral Side ◽  
New Taxon ◽  
Caudal Vertebra

Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, ‘wing-like’ transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian.

Morphology of the atlas-axis complex of the late Palaeozoic tetrapod suborders Diadectomorpha and Seymouriamorpha

1992 ◽  
Vol 336 (1277) ◽  
pp. 259-273 ◽  
Keyword(s):  
Posterior Margin ◽  
Dorsal Surface ◽  
Neural Spine ◽  
Neural Arch ◽  
Total Height ◽  
Late Palaeozoic

The atlas-axis complexes of the better-known genera of the Permo-Pennsylvanian tetrapod suborder Diadectomorpha are described and compared with those of other late Palaeozoic tetrapods. One new synapomorphy of the Diadectomorpha is identified: a large, anteriorly directed, midventral, projection of the axial intercentrum that articulates with a midventral furrow on the posterior margin of the atlantalintercentrum . Within the Diadectomorpha diadectids are apomorphic in possessing a large, anteriorly tapering axial neural spine, that accounts for approximately 40% of the total height of the axis; Limnoscelis is apomorphic in having divided parapophyseal facets of the atlantal intercentrum and anteriorly directed ventral processes of the atlantal intercentrum . Relative to the atlas-axis complex in the more primitive amphibian suborder Seymouriamorpha, that of diadectomorphs and other basal amniotes share two derived features: the atlantal pleurocentrum is fused to the dorsal surface of the axial intercentrum , except in Tseajaia where the elements are not fused but are positioned similarly; and the axial pleurocentrum and neural arch are fused in all observable stages of ontogeny. Reinterpretation of the atlantal neural arch in Seymouria indicates that it does not possess neural spines, a feature it shares with the Diadectomorpha and basal amniotes.

A new species of Largocephalosaurus (Diapsida: Saurosphargidae), with implications for the morphological diversity and phylogeny of the group

2013 ◽  
Vol 151 (1) ◽  
pp. 100-120 ◽  
Author(s):  
CHUN LI ◽  
DA-YONG JIANG ◽  
LONG CHENG ◽  
XIAO-CHUN WU ◽  
OLIVIER RIEPPEL
Keyword(s):  
New Species ◽  
Type Species ◽  
Morphological Diversity ◽  
Transverse Process ◽  
Sister Group ◽  
The Body ◽  
Current Evidence ◽  
Diagnostic Features ◽  
Additional Information ◽  
A New Species

AbstractLargocephalosaurus polycarpon Cheng et al. 2012a was erected after the study of the skull and some parts of a skeleton and considered to be an eosauropterygian. Here we describe a new species of the genus, Largocephalosaurus qianensis, based on three specimens. The new species provides many anatomical details which were described only briefly or not at all in the type species, and clearly indicates that Largocephalosaurus is a saurosphargid. It differs from the type species mainly in having three premaxillary teeth, a very short retroarticular process, a large pineal foramen, two sacral vertebrae, and elongated small granular osteoderms mixed with some large ones along the lateral most side of the body. With additional information from the new species, we revise the diagnosis and the phylogenetic relationships of Largocephalosaurus and clarify a set of diagnostic features for the Saurosphargidae Li et al. 2011. Largocephalosaurus is characterized primarily by an oval supratemporal fenestra, an elongate dorsal ‘rib-basket’, a narrow and elongate transverse process of the dorsal vertebrae, and the lack of a complete dorsal carapace of osteoderms. The Saurosphargidae is distinct mainly in having a retracted external naris, a jugal–squamosal contact, a large supratemporal extensively contacting the quadrate shaft, a leaf-like tooth crown with convex labial surface and concave lingual surface, a closed dorsal ‘rib-basket’, many dorsal osteoderms, a large boomerang-like or atypical T-shaped interclavicle. Current evidence suggests that the Saurosphargidae is the sister-group of the Sauropterygia and that Largocephalosaurus is the sister-group of the Saurosphargis–Sinosaurosphargis clade within the family.

The atlas-axis complex in the late Paleozoic genus Diadectes and the characteristics of the atlas-axis complex across the amphibian to amniote transition

1991 ◽  
Vol 65 (6) ◽  
pp. 973-983 ◽  
Author(s):  
Stuart S. Sumida ◽  
R. Eric Lombard
Keyword(s):  
Late Paleozoic ◽  
Neural Spine ◽  
Early Permian ◽  
Neural Arch ◽  
Exposure Fusion

The atlas-axis complex in the Early Permian diadectomorph Diadectes is shown to be similar to those of a variety of primitive amniotes. Diadectes does not possess elements in addition to the standard complement seen in advanced batrachosaurs and primitive amniotes as previously thought. Characteristics of the complex include: paired, well-developed proatlases and atlantal neural arches, lack of atlantal neural spines, an extremely robust atlantal intercentrum, fusion of the atlantal pleurocentrum and axial intercentrum, a large anterior projection of the axial intercentrum, exclusion of the atlantal pleurocentrum from ventral exposure, fusion of axial neural arch and pleurocentrum, and a robustly developed axial neural spine. An analysis of the transformations of the atlas-axis complex in advanced anthracosaurs and primitive amniotes indicates that many of the characteristics of the complex previously thought to be definitive of amniotes or reptiles appear to be conditions common to Diadectes plus Amniota.

scholarly journals An anterior sauropod caudal from the Peterborough Oxford Clay: Whose tail is it anyway?

2017 ◽  
Author(s):  
Femke M Holwerda ◽  
Jeff J Liston
Keyword(s):  
Species Diversity ◽  
Middle Jurassic ◽  
Articular Surface ◽  
Transverse Process ◽  
Ventral Surface ◽  
Post Mortem ◽  
Caudal Vertebra ◽  
Marine Fauna ◽  
Posterior Side ◽  
Neural Canal

The Callovian Oxford Clay of England has yielded a rich and diverse marine fauna, mainly discovered and described by Alfred Leeds. However, occasionally it also brought forth terrestrial fossils, including four isolated cases of sauropod remains, one of a stegosaurid, and another of a dryosaurid. Thus far, only Cetiosaurus oxoniensis and Cetiosauriscus stewarti are confirmed sauropod taxa from these beds. Here, we describe an isolated sauropod anterior caudal vertebra from the Oxford Clay near Peterborough. Incomplete, it has been immersed in seawater post-mortem, indicated by the adhesion of molluscs, but some characters can nevertheless be used for diagnosis and comparisons. The anterior articular surface is round, whereas the posterior articular surface is heart- shaped, as in many eusauropods, including Cetiosaurus. Interestingly, the ventral surface shows a keel-like structure; a character shared with neosauropods (e.g. Barosaurus) but also with an as yet unnamed Middle Jurassic sauropod caudal from York, UK. The posterior side of the neural canal is teardrop-shaped, a character shared with most basal eusauropods. Below the posterior neural canal, a lip-like structure seems to be present; a character which is shared with Cetiosaurus. However, the anterior caudal transverse process (ACTP) complex is similar to, although more pronounced than Cetiosauriscus, being more similar to more derived sauropods (Neosauropoda). Thus, an incomplete isolated element may help elucidate sauropod species diversity and dispersal in the Middle Jurassic of England.

scholarly journals A new large-bodied thalattosuchian crocodyliform from the Lower Jurassic (Toarcian) of Hungary, with further evidence of the mosaic acquisition of marine adaptations in Metriorhynchoidea

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4668 ◽  
Author(s):  
Attila Ősi ◽  
Mark T. Young ◽  
András Galácz ◽  
Márton Rabi
Keyword(s):  
Body Length ◽  
Mediterranean Region ◽  
Vertebral Column ◽  
Phylogenetic Analyses ◽  
Lower Jurassic ◽  
Sister Taxon ◽  
Neural Spine ◽  
Caudal Vertebra ◽  
Postcranial Remains ◽  
Marine Adaptations

Based on associated and three-dimensionally preserved cranial and postcranial remains, a new thalattosuchian crocodyliform,Magyarosuchus fitosigen. et sp. nov. from the Lower Jurassic (Upper Toarcian) Kisgerecse Marl Formation, Gerecse Mountains, Hungary is described here. Phylogenetic analyses using three different datasets indicate thatM. fitosiis the sister taxon ofPelagosaurus typusforming together the basal-most sub-clade of Metriorhynchoidea. With an estimated body length of 4.67–4.83 mM. fitosiis the largest known non-metriorhynchid metriorhynchoid. Besides expanding Early Jurassic thalattosuchian diversity, the new specimen is of great importance since, unlike most contemporaneous estuarine, lagoonal or coastal thalattosuchians, it comes from an ‘ammonitico rosso’ type pelagic deposit of the Mediterranean region of the Tethys. A distal caudal vertebra having an unusually elongate and dorsally projected neural spine implies the presence of at least a rudimentary hypocercal tail fin and a slight ventral displacement of the distal caudal vertebral column in this basal metriorhynchoid. The combination of retaining heavy dorsal and ventral armors and having a slight hypocercal tail is unique, further highlighting the mosaic manner of marine adaptations in Metriorhynchoidea.

A possible Pararcus diepenbroeki vertebra from the Vossenveld Formation (Triassic, Anisian), Winterswijk, the Netherlands

2016 ◽  
Vol 96 (1) ◽  
pp. 63-68 ◽  
Author(s):  
M.A.D. During ◽  
D.F.A.E. Voeten ◽  
A.S. Schulp ◽  
J.W.F. Reumer
Keyword(s):  
The Netherlands ◽  
Transverse Process ◽  
Neural Spine ◽  
Dorsal Region ◽  
Tentative Identification ◽  
Adult Specimen ◽  
Anatomical Position

AbstractAn isolated, completely ossified vertebra tentatively ascribed to the non-cyamodontid placodont Pararcus diepenbroeki is described from the Anisian Vossenveld Formation in Winterswijk, the Netherlands, and compared to other material from the same locality. This fossil is the first completely ossified vertebra of the taxon and most likely originates from an adult specimen. It was recovered c. 16 m deeper in the stratigraphy than previously described material of the species, which is thus far known only from Winterswijk. Based on the slanting angle of the transverse process, the vertebra is interpreted to originate from the dorsal region. Besides the overall agreements in morphology that warrant a tentative identification as Pararcus diepenbroeki, the newly described vertebra deviates from other known Pararcus vertebrae in the presence of a longer, well-ossified neural spine and a strongly constricted, less pachyostotic and ovaloid vertebral centrum. General agreement in morphology with previously described vertebrae suggests this novel condition indicates a different anatomical position and perhaps a varied ossification pattern.

A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the Cretaceous of Morocco

2013 ◽  
Vol 50 (6) ◽  
pp. 636-649 ◽  
Author(s):  
Bradley McFeeters ◽  
Michael J. Ryan ◽  
Sanja Hinic-Frlog ◽  
Claudia Schröder-Adams
Keyword(s):  
Phylogenetic Analysis ◽  
Diagnostic Character ◽  
Neural Spine ◽  
Dorsal Margin ◽  
Neural Arch ◽  
Anterior Dorsal ◽  
Neural Canal ◽  
Valid Taxon

The original hypodigm of the controversial mid-Cretaceous Moroccan dinosaur Sigilmassasaurus brevicollis is redescribed, and the diagnosis of the taxon is revised. Unambiguously referred material is restricted to cervical and anterior dorsal vertebrae sharing apomorphies with the holotype. A newly recognized diagnostic character of Sigilmassasaurus is the absence of anterior and posterior interzygapophyseal laminae of the neural arch, so that the neural spine directly meets the dorsal margin of the neural canal. A phylogenetic analysis supports the inclusion of Sigilmassasaurus in Tetanurae but not in Carcharodontosauridae. Sigilmassasaurus is distinct from all other theropods known from comparable material and is thus retained as a valid taxon.

scholarly journals A Varanid Lizard (Squamata: Varanidae) from the Early Eocene of Kirghizia

2011 ◽  
Vol 4 (2) ◽  
pp. 143-147 ◽  
Author(s):  
Alexander O. Averianov ◽  
Igor G. Danilov
Keyword(s):  
Neural Spine ◽  
New Taxon ◽  
Early Eocene ◽  
Neural Arch

Three vertebrae of a large varanid lizard from the early Eocene Andarak 2 locality in Kirghizia are described. The sacral and proximal postsacral vertebrae are each characterized by a short dorso-ventrally deep centrum and a neural arch lacking the neural spine. The material is assigned to ?Saniwa sp., probably representing a new taxon of Varanidae.

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