Dataset Information

A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia.

ABSTRACT: A new giant sauropod, Australotitan cooperensis gen. et sp. nov., represents the first record of dinosaurs from the southern-central Winton Formation of the Eromanga Basin, Australia. We estimate the type locality to be 270-300 m from the base of the Winton Formation and compare this to the semi-contemporaneous sauropod taxa, Diamantinasaurus matildae Hocknull et al., 2009, Wintonotitan wattsi Hocknull et al., 2009 and Savannasaurus elliottorum Poropat et al., 2016. The new titanosaurian is the largest dinosaur from Australia as represented by osteological remains and based on limb-size comparisons it reached a size similar to that of the giant titanosaurians from South America. Using 3-D surface scan models we compare features of the appendicular skeleton that differentiate Australotitan cooperensis gen. et sp. nov. as a new taxon. A key limitation to the study of sauropods is the inability to easily and directly compare specimens. Therefore, 3-D cybertypes have become a more standard way to undertake direct comparative assessments. Uncoloured, low resolution, and uncharacterized 3-D surface models can lead to misinterpretations, in particular identification of pre-, syn- and post-depositional distortion. We propose a method for identifying, documenting and illustrating these distortions directly onto the 3-D geometric surface of the models using a colour reference scheme. This new method is repeatable for researchers when observing and documenting specimens including taphonomic alterations and geometric differences. A detailed comparative and preliminary computational phylogenetic assessment supports a shared ancestry for all four Winton Formation taxa, albeit with limited statistical support. Palaeobiogeographical interpretations from these resultant phylogenetic hypotheses remain equivocal due to contrary Asian and South American relationships with the Australian taxa. Temporal and palaeoenvironmental differences between the northern and southern-central sauropod locations are considered to explain the taxonomic and morphological diversity of sauropods from the Winton Formation. Interpretations for this diversity are explored, including an eco-morphocline and/or chronocline across newly developed terrestrial environments as the basin fills.

SUBMITTER: Hocknull SA

PROVIDER: S-EPMC8191491 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The Australian Mesozoic crocodyliform record is sparse in comparison to other Gondwanan localities. A single formally-named taxon is known from this interval; Isisfordia duncani (Winton Formation, Albian-Turonian, Queensland). We present a previously undescribed crocodyliform braincase from the Griman Creek Formation (Cenomanian), New South Wales, which we assign to Isisfordia molnari sp. nov. Assignment to the genus is based on the possession of a newly-defined autapomorphy of Isisfordia: a broadly exposed prootic within the supratemporal foramen. A second autapomorphy of I. duncani (maximum diameter of the caudal aperture of the cranioquadrate siphonium approximately one-third the mediolateral width of the foramen magnum, with the lateral wall of the caudal aperture formed exclusively by the quadrate) may also be present in I. molnari; however, definitive recognition of this feature is marred by incomplete preservation. The new taxon is differentiated from I. duncani based on the absence of a median ridge on the parietal, and the lack of characteristic ridges on the parietal that form the medial margin of the supratemporal foramina. Reanalysis of a second specimen (the former holotype of the nomen dubium,'Crocodylus (Bottosaurus) selaslophensis') allows for its referral to the genus Isisfordia. Crucial to this reappraisal is the reinterpretation of the specimen as a partial maxilla, not the dentary as previously thought. This maxillary fragment possesses specific characteristics shared only with I. duncani; namely an alveolar groove. However, several key features differentiate the maxillary fragment from I. duncani, specifically the presence of continuous alveolar septa, the thickening of the medial alveolar rim, and the alveolar and crown base morphology. These findings constitute the first evidence of Isisfordia outside of the type locality and indicate its widespread occurrence on the freshwater floodplains along the eastern margin of the epeiric Eromanga Sea during the Albian-Cenomanian.

Project description:BackgroundTroodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains.Methodology/principal findingsHere we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes.Conclusion/significanceTalos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.

Dataset Information

A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets