scholarly journals An unusual archosauriform tooth increases known tetrapod diversity in the lower portion of the Chinle Formation (Late Triassic) of southeastern Utah, USA

2015 ◽  
Author(s):  
Andres Lopez ◽  
Isabella St. Aude ◽  
David Alderete ◽  
David Alvarez ◽  
Hannah Aultman ◽  
...  
Keyword(s):  
Upper Triassic ◽  
Lower Portion ◽  
Late Triassic ◽  
Unique Combination ◽  
Chinle Formation ◽  
Using Data

An unusual tetrapod tooth was discovered in the Upper Triassic Chinle Formation of southeastern Utah. The tooth was originally hypothesized to pertain to Revueltosaurus, but further investigations have rejected that hypothesis. In this paper, we compare MNA V10668 to other known fossil tooth crowns from the Chinle Formation and assign the tooth to the least inclusive clade currently available, Archosauriformes, based on the presence of mesial and distal serrations, a distal keel, and a conical mesiodistal profile. Using data found in other publications and pictures of other teeth, we compare this specimen to other Triassic dental taxa. MNA V10668 shares some similarities with Crosbysaurus, Tecovasaurus, and several other named taxa, including a teardrop-shaped labiolingual profile, but possesses a unique combination of characteristics not found in other archosauromorph teeth. This increases the known diversity of archosauromorphs from the Chinle Formation and represents the first tooth of this morphotype to be found from Utah in the Late Triassic.

scholarly journals An unusual archosauriform tooth increases known tetrapod diversity in the lower portion of the Chinle Formation (Late Triassic) of southeastern Utah, USA

2015 ◽  
Author(s):  
Andres Lopez ◽  
Isabella St. Aude ◽  
David Alderete ◽  
David Alvarez ◽  
Hannah Aultman ◽  
...  
Keyword(s):  
Upper Triassic ◽  
Lower Portion ◽  
Late Triassic ◽  
Unique Combination ◽  
Chinle Formation ◽  
Using Data

An unusual tetrapod tooth was discovered in the Upper Triassic Chinle Formation of southeastern Utah. The tooth was originally hypothesized to pertain to Revueltosaurus, but further investigations have rejected that hypothesis. In this paper, we compare MNA V10668 to other known fossil tooth crowns from the Chinle Formation and assign the tooth to the least inclusive clade currently available, Archosauriformes, based on the presence of mesial and distal serrations, a distal keel, and a conical mesiodistal profile. Using data found in other publications and pictures of other teeth, we compare this specimen to other Triassic dental taxa. MNA V10668 shares some similarities with Crosbysaurus, Tecovasaurus, and several other named taxa, including a teardrop-shaped labiolingual profile, but possesses a unique combination of characteristics not found in other archosauromorph teeth. This increases the known diversity of archosauromorphs from the Chinle Formation and represents the first tooth of this morphotype to be found from Utah in the Late Triassic.

scholarly journals An unusual archosauriform tooth increases known tetrapod diversity in the lower Chinle Formation (Late Triassic) of southeastern Utah

2015 ◽  
Author(s):  
Andres Lopez ◽  
Isabella St. Aude ◽  
David Alderete ◽  
David Alvarez ◽  
Hannah Aultman ◽  
...  
Keyword(s):  
Late Triassic ◽  
Chinle Formation ◽  
Triassic Period ◽  
Using Data

An unusual tetrapod tooth was discovered in the Late Triassic Chinle Formation of southeastern Utah. The tooth was originally thought to belong to Revueltosaurus but further investigations have rejected that hypothesis. In this paper we compare MNA V10668 to other known fossil teeth found in the Chinle Formation and identify the least inclusive clade it may belongs to. Using data found in other publications and pictures of other teeth, we compare this specimen to other Triassic dental taxa. MNA V10668 shares some similarities with Crosbysaurus, Tecovasaurus, and several other named taxa but possesses unique characteristics not found in other diapsid teeth. We conclude that it is most likely an archosauromorph and probably an archosauriform. This increases the known diversity of tetrapods from the Chinle Formation and represents the first tooth morphotype completely unique to Utah in the Late Triassic Period.

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.

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 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.

scholarly journals Non-dinosaurian dinosauromorphs from the Chinle Formation (Upper Triassic) of the Eagle Basin, northern Colorado: Dromomeron romeri (Lagerpetidae) and a new taxon, Kwanasaurus williamparkeri (Silesauridae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7551 ◽  
Author(s):  
Jeffrey W. Martz ◽  
Bryan J. Small
Keyword(s):  
Articular Surface ◽  
Upper Triassic ◽  
Late Triassic ◽  
New Taxon ◽  
Dietary Specialization ◽  
Sister Clade ◽  
Chinle Formation ◽  
Northern Colorado ◽  
Land Vertebrate ◽  
Early Late

The “red siltstone” member of the Upper Triassic Chinle Formation in the Eagle Basin of Colorado contains a diverse assemblage of dinosauromorphs falling outside of Dinosauria. This assemblage is the northernmost known occurrence of non-dinosaurian dinosauromorphs in North America, and probably falls within the Revueltian land vertebrate estimated biochronozone (215–207 Ma, middle to late Norian). Lagerpetids are represented by proximal femora and a humerus referable to Dromomeron romeri. Silesaurids (non-dinosaurian dinosauriforms) are the most commonly recovered dinosauromorph elements, consisting of dentaries, maxillae, isolated teeth, humeri, illia, femora, and possibly a scapula and tibiae. These elements represent a new silesaurid, Kwanasaurus williamparkeri, gen. et sp. nov., which possesses several autapomorphies: a short, very robust maxilla with a broad ascending process, a massive ventromedial process, a complex articular surface for the lacrimal and jugal, and 12 teeth; 14 dentary teeth; an ilium with an elongate and blade-like preacetabular process and concave acetabular margin; a femur with an extremely thin medial distal condyle and a depression on the distal end anterior to the crista tibiofibularis. The recognition of K. williamparkeri further demonstrates the predominantly Late Triassic diversity and widespread geographic distribution across Pangea of the sister clade to Asilisaurus, here named Sulcimentisauria. Silesaurid dentition suggests a variety of dietary specializations from faunivory and omnivory in the Middle Triassic and early Late Triassic (Carnian), to herbivory in the Late Triassic (Carnian and Norian), with the latter specialization possibly coinciding with the radiation of Sulcimentisauria across Pangea. The extremely robust maxilla and folidont teeth of K. williamparkei may represent a strong herbivorous dietary specialization among silesaurids.

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

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2411 ◽  
Author(s):  
William G. Parker
Keyword(s):  
Morphological Feature ◽  
National Park ◽  
Vertebral Column ◽  
Dorsal Surface ◽  
Upper Triassic ◽  
Late Triassic ◽  
Naming Convention ◽  
Holotype Specimen ◽  
Posteromedial Corner ◽  
Chinle Formation

Aetosaurians are some of the most common fossils collected from the Upper Triassic Chinle Formation of Arizona, especially at the Petrified Forest National Park (PEFO). Aetosaurians collected from lower levels of the park includeDesmatosuchus spurensis,Paratypothorax,Adamanasuchus eisenhardtae,Calyptosuchus wellesi, andScutarx deltatylus. Four partial skeletons collected from the park between 2002 and 2009 represent the holotype and referred specimens ofScutarx deltatylus. These specimens include much of the carapace, as well as the vertebral column, and shoulder and pelvic girdles, and a new naming convention proposed for osteoderms descriptions better differentiates portions of the carapace and ventral armor. A partial skull from the holotype specimen represents the first aetosaur skull recovered and described from Arizona since the 1930s. The key morphological feature distinguishingScutarx deltatylusis the presence of a prominent, triangular boss located in the posteromedial corner of the dorsal surface of the dorsal paramedian osteoderms.Scutarx deltatyluscan be distinguished from closely related formsCalyptosuchus wellesiandAdamanasuchus eisenhardtaenot only morphologically, but also stratigraphically. Thus,Scutarx deltatylusis potentially an index taxon for the upper part of the Adamanian biozone.

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