A new aetosaur genus (Archosauria: Pseudosuchia) from the early Late Triassic of southern Brazil

Zootaxa ◽  
2012 ◽  
Vol 3166 (1) ◽  
pp. 1 ◽  
Author(s):  
JULIA B. DESOJO ◽  
MARTÍN D. EZCURRA ◽  
EDIO E. KISCHLAT
Keyword(s):  
Cervical Vertebrae ◽  
Cladistic Analysis ◽  
Axial Skeleton ◽  
Late Triassic ◽  
South American ◽  
Southern Brazil ◽  
Caudal Vertebra ◽  
Caudal Vertebrae ◽  
Santa Maria ◽  
Early Late

We describe the new aetosaur Aetobarbakinoides brasiliensis gen. et sp. nov. from the early Late Triassic (late Carnian-early Norian) Brazilian Santa Maria Formation. The holotype is composed of a partial postcranium including several cer-vical and dorsal vertebrae and ribs, one anterior caudal vertebra, right scapula, right humerus, right tibia, partial right pes,and anterior and mid-dorsal paramedian osteoderms. Aetobarbakinoides is differentiated from other aetosaurs by the pres-ence of cervical vertebrae with widely laterally extended prezygapophyses, mid-cervical vertebrae with anterior articularfacet width more than 1.2 times wider than the posterior one, anterior caudal vertebrae with extremely anteroposteriorlyshort prezygapophyses, elongated humerus and tibia in relation to the axial skeleton, and paramedian osteoderms with aweakly raised anterior bar. A cladistic analysis recovered the new species as more derived than the South American generaAetosauroides (late Carnian-early Norian) and Neoaetosauroides (late Norian-Rhaetian), and it is nested as the sister-tax-on of an unnamed clade, composed of Typothoracisinae and Desmatosuchinae, due to the absence of a ventral keel in thecervical vertebrae. Aetobarbakinoides presents a skeletal anatomy previously unknown among South American aetosaurs,with the combination of presacral vertebrae with hyposphene, anteroposteriorly short and unkeeled cervical vertebrae,gracile limbs, and paramedian osteoderms with a weakly raised anterior bar. Aetobarbakinoides is among the oldest knownaetosaurs together with Aetosauroides from Argentina and Brazil and Stagonolepis robertsoni from Scotland, indicatinga widely distributed early record for the group. In addition, the recognition of a suite of derived features in Aetobarbaki-noides, which is one of the oldest known aetosaurs, is in agreement with an older origin for the group, as it is expected by the extensive ghost lineages at the base of the main pseudosuchian clades.

scholarly journals A new small-bodied ornithopod (Dinosauria, Ornithischia) from a deep, high-energy Early Cretaceous river of the Australian–Antarctic rift system

PeerJ ◽  
2018 ◽  
Vol 5 ◽  
pp. e4113 ◽  
Author(s):  
Matthew C. Herne ◽  
Alan M. Tait ◽  
Vera Weisbecker ◽  
Michael Hall ◽  
Jay P. Nair ◽  
...  
Keyword(s):  
Cladistic Analysis ◽  
Body Part ◽  
High Energy ◽  
Qualitative Assessment ◽  
Rift System ◽  
South American ◽  
Caudal Vertebra ◽  
Anatomical Features ◽  
Southeastern Australia ◽  
Caudal Vertebrae

A new small-bodied ornithopod dinosaur,Diluvicursor pickeringi, gen. et sp. nov., is named from the lower Albian of the Eumeralla Formation in southeastern Australia and helps shed new light on the anatomy and diversity of Gondwanan ornithopods. Comprising an almost complete tail and partial lower right hindlimb, the holotype (NMV P221080) was deposited as a carcass or body-part in a log-filled scour near the base of a deep, high-energy river that incised a faunally rich, substantially forested riverine floodplain within the Australian–Antarctic rift graben. The deposit is termed the ‘Eric the Red West Sandstone.’ The holotype, interpreted as an older juvenile ∼1.2 m in total length, appears to have endured antemortem trauma to the pes. A referred, isolated posterior caudal vertebra (NMV P229456) from the holotype locality, suggestsD. pickeringigrew to at least 2.3 m in length.D. pickeringiis characterised by 10 potential autapomorphies, among which dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae are a visually defining combination of features. These features suggestD. pickeringihad robust anterior caudal musculature and strong locomotor abilities. Another isolated anterior caudal vertebra (NMV P228342) from the same deposit, suggests that the fossil assemblage hosts at least two ornithopod taxa.D. pickeringiand two stratigraphically younger, indeterminate Eumeralla Formation ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, the tail ofD. pickeringiis far shorter than that of NMV P185992/P185993 and its pes more robust than that of NMV P186047. Preliminary cladistic analysis, utilising three existing datasets, failed to resolveD. pickeringibeyond a large polytomy of Ornithopoda. However, qualitative assessment of shared anatomical features suggest that the Eumeralla Formation ornithopods, South AmericanAnabisetia saldiviaiandGasparinisaura cincosaltensis, Afro-Laurasian dryosaurids and possibly AntarcticMorrosaurus antarcticusshare a close phylogenetic progenitor. Future phylogenetic analysis with improved data on Australian ornithopods will help to test these suggested affinities.

The anatomy and phylogenetic position of the Triassic dinosaur Staurikosaurus pricei Colbert, 1970

Zootaxa ◽  
2009 ◽  
Vol 2079 (1) ◽  
pp. 1-56 ◽  
Author(s):  
JONATHAS DE SOUZA BITTENCOURT ◽  
ALEXANDER WILHELM ARMIN KELLNER
Keyword(s):  
Morphological Characters ◽  
Late Triassic ◽  
Sister Taxon ◽  
Phylogenetic Position ◽  
Southern Brazil ◽  
Anatomical Features ◽  
Phylogenetic Studies ◽  
Caudal Vertebrae ◽  
Close Relationship ◽  
Santa Maria

We redescribe the holotype of the saurischian dinosaur Staurikosaurus pricei Colbert, 1970 from Late Triassic Santa Maria Formation (southern Brazil), following additional preparation that revealed new anatomical features. A revised diagnosis is proposed and the published synapomorphies for Dinosauria and less inclusive clades (e.g. Saurischia) are evaluated for this species. Some characters previously identified as present in the holotype, including the intramandibular joint, hyposphene-hypantrum articulations in dorsal vertebrae, and a cranial trochanter and trochanteric shelf on the femur, cannot be confirmed due to poor preservation or are absent in the available material. In addition, postcranial characters support a close relationship between S. pricei and Herrerasaurus ischigualastensis Reig, 1963 (Late Triassic, Argentina), forming the clade Herrerasauridae. Several pelvic and vertebral characters support the placement of S. pricei as a saurischian dinosaur. Within Saurischia, characters observed in the holotype, including the anatomy of the dentition and caudal vertebrae, support theropod affinities. However, the absence of some characters observed in the clades Theropoda and Sauropodomorpha suggests that S. pricei is not a member of Eusaurischia. Most morphological characters discussed in previous phylogenetic studies cannot be assessed for S. pricei because of the incompleteness of the holotype and only known specimen. The phylogenetic position of S. pricei is constrained by that of its sister taxon H. ischigualastensis, which is known from much more complete material.

scholarly journals Anatomy of the dinosaur Pampadromaeus barberenai (Saurischia—Sauropodomorpha) from the Late Triassic Santa Maria Formation of southern Brazil

PLoS ONE ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. e0212543 ◽  
Author(s):  
Max Cardoso Langer ◽  
Blair Wayne McPhee ◽  
Júlio César de Almeida Marsola ◽  
Lúcio Roberto-da-Silva ◽  
Sérgio Furtado Cabreira
Keyword(s):  
Late Triassic ◽  
Southern Brazil ◽  
Santa Maria

scholarly journals A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona

2020 ◽  
Vol 94 (S78) ◽  
pp. 1-103 ◽  
Author(s):  
Adam D. Marsh ◽  
Timothy B. Rowe
Keyword(s):  
Phylogenetic Analyses ◽  
Cervical Vertebrae ◽  
Pop Culture ◽  
Single Species ◽  
Axial Skeleton ◽  
Late Triassic ◽  
Monophyletic Clade ◽  
Navajo Nation ◽  
Northern Arizona ◽  
Nasal Process

AbstractDilophosaurus wetherilli was the largest animal known to have lived on land in North America during the Early Jurassic. Despite its charismatic presence in pop culture and dinosaurian phylogenetic analyses, major aspects of the skeletal anatomy, taxonomy, ontogeny, and evolutionary relationships of this dinosaur remain unknown. Skeletons of this species were collected from the middle and lower part of the Kayenta Formation in the Navajo Nation in northern Arizona. Redescription of the holotype, referred, and previously undescribed specimens of Dilophosaurus wetherilli supports the existence of a single species of crested, large-bodied theropod in the Kayenta Formation. The parasagittal nasolacrimal crests are uniquely constructed by a small ridge on the nasal process of the premaxilla, dorsoventrally expanded nasal, and tall lacrimal that includes a posterior process behind the eye. The cervical vertebrae exhibit serial variation within the posterior centrodiapophyseal lamina, which bifurcates and reunites down the neck. Iterative specimen-based phylogenetic analyses result in each of the additional specimens recovered as the sister taxon to the holotype. When all five specimens are included in an analysis, they form a monophyletic clade that supports the monotypy of the genus. Dilophosaurus wetherilli is not recovered as a ceratosaur or coelophysoid, but is instead a non-averostran neotheropod in a grade with other stem-averostrans such as Cryolophosaurus ellioti and Zupaysaurus rougieri. We did not recover a monophyletic ‘Dilophosauridae.’ Instead of being apomorphic for a small clade of early theropods, it is more likely that elaboration of the nasals and lacrimals of stem-averostrans is plesiomorphically present in early ceratosaurs and tetanurans that share those features. Many characters of the axial skeleton of Dilophosaurus wetherilli are derived compared to Late Triassic theropods and may be associated with macropredation and an increase in body size in Theropoda across the Triassic-Jurassic boundary.

scholarly journals Anatomo-radiographic description of the axial skeleton of the crab-eating fox (Cerdocyon thous)

2012 ◽  
Vol 32 (suppl 1) ◽  
pp. 01-03 ◽  
Author(s):  
Janaína D. Barisson ◽  
Cristiane H. Louro ◽  
Sheila J.T. Dias ◽  
Flávio S. Jojima ◽  
Murilo S. Ferreira ◽  
...  
Keyword(s):  
Cervical Vertebrae ◽  
Spinous Process ◽  
Lumbar Vertebrae ◽  
Axial Skeleton ◽  
The Other ◽  
Domestic Dog ◽  
Thoracic Vertebrae ◽  
The Third ◽  
Caudal Vertebrae ◽  
Cerdocyon Thous

The aim of this study was to describe the axial skeleton of a wild Brazilian carnivorous, the crab-eating fox (Cerdocyon thous). Five specimens of crab-eating fox were previously unfrozen for radiographic exams and their bones went through dissection and chemical maceration. This animal presents seven cervical vertebrae, and from the third on, they become shorter and wider than the other ones e the spinous process was makeable from the fifth cervical vertebrae on. There are thirteen thoracic vertebrae and the spinous process of the lumbar vertebrae, which are seven, decreases from the fifth on. The sacrum is formed by two vertebrae and there are twenty or twenty one caudal vertebrae. It can be concluded that the crab-eating fox axial skeleton is similar to that of the domestic dog.

scholarly journals Northward dispersal of dinosaurs from Gondwana to Greenland at the mid-Norian (215–212 Ma, Late Triassic) dip in atmospheric pCO2

2021 ◽  
Vol 118 (8) ◽  
pp. e2020778118
Author(s):  
Dennis V. Kent ◽  
Lars B. Clemmensen
Keyword(s):  
Northern Hemisphere ◽  
Additional Data ◽  
Late Triassic ◽  
Southern Brazil ◽  
Northwestern Argentina ◽  
Terrestrial Vertebrates ◽  
Composite Section ◽  
Age Model ◽  
Main Barrier ◽  
Early Late

The earliest dinosaurs (theropods and sauropodomorphs) are found in fossiliferous early Late Triassic strata dated to about 230 million years ago (Ma), mainly in northwestern Argentina and southern Brazil in the Southern Hemisphere temperate belt of what was Gondwana in Pangea. Sauropodomorphs, which are not known for the entire Triassic in then tropical North America, eventually appear 15 million years later in the Northern Hemisphere temperate belt of Laurasia. The Pangea supercontinent was traversable in principle by terrestrial vertebrates, so the main barrier to be surmounted for dispersal between hemispheres was likely to be climatic; in particular, the intense aridity of tropical desert belts and unstable climate in the equatorial humid belt accompanying high atmospheric pCO2 that characterized the Late Triassic. We revisited the chronostratigraphy of the dinosaur-bearing Fleming Fjord Group of central East Greenland and, with additional data, produced a correlation of a detailed magnetostratigraphy from more than 325 m of composite section from two field areas to the age-calibrated astrochronostratigraphic polarity time scale. This age model places the earliest occurrence of sauropodomorphs (Plateosaurus) in their northernmost range to ∼214 Ma. The timing is within the 215 to 212 Ma (mid-Norian) window of a major, robust dip in atmospheric pCO2 of uncertain origin but which may have resulted in sufficiently lowered climate barriers that facilitated the initial major dispersal of the herbivorous sauropodomorphs to the temperate belt of the Northern Hemisphere. Indications are that carnivorous theropods may have had dispersals that were less subject to the same climate constraints.

Trucidocynodon riograndensis gen. nov. et sp. nov. (Eucynodontia), a new cynodont from the Brazilian Upper Triassic (Santa Maria Formation)

Zootaxa ◽  
2010 ◽  
Vol 2382 (1) ◽  
pp. 1 ◽  
Author(s):  
TÉO VEIGA DE OLIVEIRA ◽  
MARINA BENTO SOARES ◽  
CESAR LEANDRO SCHULTZ
Keyword(s):  
Upper Triassic ◽  
New Taxon ◽  
Southern Brazil ◽  
Morphological Gradient ◽  
Caudal Vertebrae ◽  
Secondary Palate ◽  
Limb Posture ◽  
Posterior Trunk ◽  
Santa Maria

An almost complete skeleton of a new carnivorous cynodont from the Upper Triassic of Southern Brazil, Trucidocynodon riograndensis gen. nov. et sp. nov., is described. The new taxon is very similar to Ecteninion lunensis Martinez et al. 1996 from Upper Triassic of Argentina (Ischigualasto Formation). Both have an elongated skull, large pterygoid flanges, a well developed orbitosphenoid, a relatively short osseous secondary palate, greatly developed canines and sectorial postcanines with posteriorly directed cusps. However, the new taxon shows some differences relative to E. lunensis such as an open pterygoparoccipital foramen, the posterior opening of the post-temporal foramen enclosed by tabular and squamosal, and upper incisors with serrated cutting edges. The more remarkable features of the postcranium of T. riograndensis are the presence of 32 presacral vertebrae, a greater number than in most of non-mammaliaform cynodonts, the accentuated lumbarisation of the posterior trunk vertebrae and a remarkable morphological gradient in the caudal vertebrae; the femur and humerus show some interesting adaptations suggesting a more upright limb posture. The overall morphology of the astragalocalcaneal complex is similar to that of Diademodon and of the therocephalian Bauria.

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