scholarly journals A new rauisuchid (Archosauria, Pseudosuchia) from the Upper Triassic (Norian) of New Mexico increases the diversity and temporal range of the clade

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2336 ◽  
Author(s):  
Emily J. Lessner ◽  
Michelle R. Stocker ◽  
Nathan D. Smith ◽  
Alan H. Turner ◽  
Randall B. Irmis ◽  
...  
Keyword(s):  
United States ◽  
New Mexico ◽  
Upper Triassic ◽  
Late Triassic ◽  
Morphological Evidence ◽  
Ventral Margin ◽  
Close Phylogenetic Relationship ◽  
Chinle Formation ◽  
Geographic Separation ◽  
A New Species

Rauisuchids are large (2–6 m in length), carnivorous, and quadrupedal pseudosuchian archosaurs closely related to crocodylomorphs. Though geographically widespread, fossils of this clade are relatively rare in Late Triassic assemblages. The middle Norian (∼212 Ma) Hayden Quarry of northern New Mexico, USA, in the Petrified Forest Member of the Chinle Formation, has yielded isolated postcranial elements and associated skull elements of a new species of rauisuchid.Vivaron haydenigen. et. sp. nov. is diagnosed by the presence of two posteriorly directed prongs at the posterior end of the maxilla for articulation with the jugal. The holotype maxilla and referred elements are similar to those of the rauisuchidPostosuchus kirkpatrickifrom the southwestern United States, butV. haydenishares several maxillary apomorphies (e.g., a distinct dropoff to the antorbital fossa that is not a ridge, a straight ventral margin, and a well defined dental groove) with the rauisuchidTeratosaurus suevicusfrom the Norian of Germany. Despite their geographic separation, this morphological evidence implies a close phylogenetic relationship betweenV. haydeniandT. suevicus. The morphology preserved in the new Hayden Quarry rauisuchidV. haydenisupports previously proposed and new synapomorphies for nodes within Rauisuchidae. The discovery ofVivaron haydenireveals an increased range of morphological disparity for rauisuchids from the low-paleolatitude Chinle Formation and a clear biogeographic connection with high paleolatitude Pangea.

New reptiles from the Upper Triassic Chinle Formation of Arizona

1987 ◽  
Vol 61 (4) ◽  
pp. 773-786 ◽  
Author(s):  
Phillip A. Murry
Keyword(s):  
United States ◽  
New Species ◽  
Great Britain ◽  
New Records ◽  
Upper Triassic ◽  
Late Triassic ◽  
Southwestern United States ◽  
Chinle Formation ◽  
A New Species

New records of Late Triassic reptiles from the Chinle Formation of Arizona include a new species of small trilophosaurid, a sphenodontid, and two taxa of eolacertilians. ?Trilophosaurus jacobsi n. sp. is a small trilophosaurid showing affinities to the type of Trilophosaurus buettneri of the southwestern United States and Variodens inopinatus from the Upper Triassic of Great Britain. A sphenodontid is also reported along with maxillae tentatively referred to the Kuehneosauridae and a jaw fragment from a subpleurodont eolacertilian with polycuspate teeth.

scholarly journals The first occurrence of the enigmatic archosaur Crosbysaurus (Heckert 2004) from the Chinle Formation of Southern Utah

2014 ◽  
Author(s):  
Robert J Gay ◽  
Isabella St. Aude
Keyword(s):  
New Mexico ◽  
Close Association ◽  
First Record ◽  
Geographic Range ◽  
Type Locality ◽  
Late Triassic ◽  
Southern Area ◽  
Chinle Formation ◽  
First Occurrence ◽  
Unique Compound

Originally identified as an ornithisichian dinosaur, Crosbysaurus has been found in New Mexico, Arizona, and the type locality in Texas. The genus has been reassessed by other workers in light of revelations about the postcrania of another putative Triassic ornithischian, Revueltosaurus. The understanding of Triassic dental faunas has become more complicated by the extreme convergence between pseudosuchian archosaurus and ornithichian dinosaur dental morphologies. We report here on a new specimen of Crosbysaurus from the Petrified Forest Member of the Chinle Formation at Comb Ridge in southeastern Utah. This new specimen is assigned to Crosbysaurus on the basis of the unique compound posterior denticles, mediolateral width, and curvature. While this specimen, MNA V10666, does not help resolve the affinities of Crosbysaurus it does represent an approximately 250 kilometer extension of the geographic range of this taxon. This is the first record of this taxon in Utah and as such it represents the northernmost known record of Crosbysaurus. This indicates that Crosbysaurus was not limited to the southern area of Chinle/Dockum deposition but instead was widespread across the paleoriver systems of the Late Triassic in western Pangea. The specimen we report on here was found in close association with a typical Late Triassic Chinle fauna, including phytosaurs, metoposaurs, and dinosauromorphs.

New cynodonts (Therapsida, Eucynodontia) from the Late Triassic of India and their significances

2020 ◽  
pp. 1-18
Author(s):  
Mohd Shafi Bhat ◽  
Sanghamitra Ray ◽  
P. M. Datta
Keyword(s):  
New Species ◽  
Upper Triassic ◽  
Intermediate Position ◽  
Late Triassic ◽  
Tooth Morphology ◽  
Crown Root ◽  
Anterior Edge ◽  
A New Species

Abstract The Upper Triassic Tiki Formation of India has yielded several new cynodont taxa, which are described on the basis of multiple isolated teeth and a jaw fragment. A new species of dromatheriid, Rewaconodon indicus, is defined by a tri- and tetracuspid asymmetric crown, long anterior edge of the major cusp a, cingular cusps d and f, and marked constriction at the crown-root junction. Another new dromatheriid, Inditherium floris n. gen. n. sp., is characterized by a broad, flower-shaped pentacuspid crown, multiple cingular cusps, and a weak lingual cingulum is also described from the same horizon. In addition, a new mammaliamorph taxon, Tikiodon cromptoni n. gen. n. sp., is established on a tooth specimen, which has a shovel-shaped crown, three closely spaced main cusps, a pronounced lingual cingulum with multiple cingular cusps, and a root of incomplete root bifurcation. Such a tooth morphology occupies an intermediate position between the non-mammalian cynodonts and the early mammals, as is evident from the co-occurrence of various cynodont dental morphotypes in the Tiki Formation. Moreover, Late Triassic cynodonts occurred along narrow belts demarcated by paleolatitudes, though the Indian fauna shows both Laurasian and Gondwanan affinities. UUID: http://zoobank.org/c2c575ad-ee23-4f33-8a30-661c548a5b17

A colorful new species of the digger wasp genus Pseudoplisus Ashmead from the Southwestern United States (Hymenoptera: Apoidea, Crabronidae)

Zootaxa ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 27-34
Author(s):  
MICHAEL OHL
Keyword(s):  
United States ◽  
New Species ◽  
New Mexico ◽  
Geographic Distribution ◽  
Color Pattern ◽  
Single Specimen ◽  
Southwestern United States ◽  
Digger Wasp ◽  
A New Species

A new species of apoid wasps, Pseudoplisus willcoxi sp. nov., is described from Arizona, New Mexico, and Colorado. It is compared with all other species currently assigned to the genus. It has a remarkable overall color pattern, unique in Pseudoplisus, and a restricted collecting record: only a single specimen was collected outside of the Willcox area in Arizona (defined here as including the Animas area, New Mexico). Additionally, of the 34 remaining specimens, one was collected in 1974 and all other after 2001. In the present paper, the new species is diagnosed, described, and the relevant characters are illustrated. The geographic distribution and its heterogeneous collecting record are briefly discussed.

scholarly journals A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell

2008 ◽  
Vol 276 (1656) ◽  
pp. 507-513 ◽  
Author(s):  
Walter G Joyce ◽  
Spencer G Lucas ◽  
Torsten M Scheyer ◽  
Andrew B Heckert ◽  
Adrian P Hunt
Keyword(s):  
New Mexico ◽  
North America ◽  
Fossil Record ◽  
De Novo ◽  
Upper Triassic ◽  
Late Triassic ◽  
Terrestrial Habitat ◽  
Turtle Shell ◽  
Shell Elements ◽  
Stem Lineage

A new, thin-shelled fossil from the Upper Triassic (Revueltian: Norian) Chinle Group of New Mexico, Chinlechelys tenertesta , is one of the most primitive known unambiguous members of the turtle stem lineage. The thin-shelled nature of the new turtle combined with its likely terrestrial habitat preference hint at taphonomic filters that basal turtles had to overcome before entering the fossil record. Chinlechelys tenertesta possesses neck spines formed by multiple osteoderms, indicating that the earliest known turtles were covered with rows of dermal armour. More importantly, the primitive, vertically oriented dorsal ribs of the new turtle are only poorly associated with the overlying costal bones, indicating that these two structures are independent ossifications in basal turtles. These novel observations lend support to the hypothesis that the turtle shell was originally a complex composite in which dermal armour fused with the endoskeletal ribs and vertebrae of an ancestral lineage instead of forming de novo. The critical shell elements (i.e. costals and neurals) are thus not simple outgrowths of the bone of the endoskeletal elements as has been hypothesized from some embryological observations.

scholarly journals Osteology of the Late Triassic aetosaur Scutarx deltatylus (Archosauria: Pseudosuchia)

2016 ◽  
Author(s):  
William G Parker
Keyword(s):  
National Park ◽  
Vertebral Column ◽  
Upper Triassic ◽  
Late Triassic ◽  
Chinle Formation ◽  
Petrified Forest National Park ◽  
Petrified Forest

Aetosaurs are some of the most common fossils collected from the Upper Triassic Chinle Formation of Arizona, especially at the Petrified Forest National Park. Four partial skeletons collected from the park from 2002 through 2009 represent the holotype and referred specimens of Scutarx deltatylus. These specimens include much of the carapace, as well as the vertebral column, and shoulder and pelvic girldles. A partial skull represents the first aetosaur skull recovered from Arizona since the 1930s. Scutarx deltatylus can be distinguished from closely related forms Calyptosuchus wellesi and Adamanasuchus eisenhardtae not only morphologically, but also stratigraphically. Thus, Scutarx deltatylus is potentially an index taxon for the upper part of the Adamanian biozone.

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