An unusual archosauriform tooth increases known tetrapod diversity in the lower portion of the Chinle Formation (Late Triassic) of southeastern Utah, USA
- Published
- Accepted
- Subject Areas
- Biodiversity, Paleontology
- Keywords
- archosaur, archosauriform, Chinle Formation, Triassic, tetrapod, dental taxon, Utah, Crosbysaurus, Revueltosaurus, phytosaur
- Copyright
- © 2015 Lopez et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
- Cite this article
- 2015. An unusual archosauriform tooth increases known tetrapod diversity in the lower portion of the Chinle Formation (Late Triassic) of southeastern Utah, USA. PeerJ PrePrints 3:e1110v3 https://doi.org/10.7287/peerj.preprints.1110v3
Abstract
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.
Author Comment
We have made changes based on the comments we have received from reviewers and feedback on the PrePrint. This manuscript was rejected in the second round of review at PeerJ. We have included additional information based on the reviewer comments in the second round of review and included the peer review history as supplemental information. We intend to take information from this manuscript and include portions of it in a larger study looking at the geology and paleobiology of The Hills Have Teeth deposit and Comb Ridge as a whole.
Supplemental Information
Figure 1: The location of Comb Ridge in the state of Utah. Modified from Gay and St. Aude (2015)
The location of Comb Ridge (star) within the state of Utah. San Juan County is highlighted. Modified from Gay and St. Aude (2015).
Figure 2: Tetrapod tooth in situ at The Hills Have Teeth (MNA locality 1724), showing the lithology of the fossil-bearing layer
Small, unidentified tetrapod in the field in May 2015 showing the lithology of the fossil-bearing layer at The Hills Have Teeth. Site is dominated by gray-white mudstone with carbonaceous clasts.
Figure 3: Photographs of MNA V10668
MNA V10668 in A) lingual, B) labial, C) distal, D) mesial, E) apical, and F) basal views. Ap, apex; RP, resorption pit. Scale bar = 1 mm.
Figure 4: Interpretive line drawing of MNA V10668
Interpretive line drawing of MNA V10668 in A) lingual, B) labial, C) distal, D) mesial, E) apical, and F) basal views. In A-D, dark gray represents missing enamel, light gray represents a resorption pit. In E and F no missing enamel is figured; dark gray represents worn apex, light gray represents resorption pit. Ap, apex; RP, resorption pit. Scale bar = 1 mm.
Figure 5: Juvenile phytosaur jaws
Juvenile phytosaur jaws. Top: PEFO 13890/MNA V1789, Macheroprosopus zunii premaxillae in A) ventral view. Bottom: MNA V3601 right dentary in B) lateral C) dorsal views. Stars show locations of selected teeth figured in Figures 6, 7, and 8.TC, tooth crowns; A, alveoli. Scale bar = 1 cm.
Figure 6: Unerupted juvenile phytosaur tooth crown
An unerupted tooth crown from a juvenile phytosaur, PEFO 13890/MNA V1789 showing distinct symmetrical tooth crown profile and lack of serrations. A, alveolus; TC, tooth crown. Scale bar = 1 mm.
Figure 7: Juvenile phytosaur dentary teeth
Close-up view of two erupted dentary teeth in the posterior portion of MNA V3601 in lateral view. Teeth are tall and conical in labiolingual and mesiodistal profiles. Teeth are also unserrated. TC, tooth crown. Scale bar = 1 mm.
Figure 8: juvenile phytosaur terminal dentary teeth
Anteriormost erupted and broken tooth crowns from MNA V3601 in dorsal view showing rounded base of crown and rounded alveoli. Both tooth fragments do not possess serrations. A, alveoli; BTC, broken tooth crown. Scale bar = 1 mm.
Editor Decision - Revision
The "revise and resubmit" decision from the academic editor, Matt Wedel, on August 25th.
Reviewer 1 - Revision Letter
This is the summary letter that Reviewer 1 wrote to accompany the annotated manuscript for the "revise and resubmit" decision we received on August 25th.
Sterling Nesbitt - Revision Letter
This is the summary letter that Sterling Nesbitt wrote to accompany the annotated manuscript for the "revise and resubmit" decision we received on August 25th.
Reviewer 1 Annotated Manuscript - Revision
Submitted manuscript annotated by Reviewer 1, received on August 25th.
Sterling Nesbitt Annotated Manuscript - Revision
Submitted manuscript annotated by Sterling Nesbitt, received on August 25th.
Authors' Rebuttal Letter
Our response to the "revise and resubmit" decision of August 25th.
Editor Decision - Rejection
The "reject" decision from the academic editor, Matt Wedel, on October 21st.
Reviewer 1 - Rejection Letter
This is the summary letter that Reviewer 1 wrote to accompany the annotated manuscript for the "reject" decision we received on October 21st.
Sterling Nesbitt - Rejection Letter
This is the summary letter that Sterling Nesbitt wrote to accompany the annotated manuscript for the "reject" decision we received on October 21st.
Reviewer 1 Annotated Manuscript - Reject
Submitted manuscript annotated by Reviewer 1, received on October 21st.
Sterling Nesbitt Annotated Manuscript - Reject
Submitted manuscript annotated by Sterling Nesbitt, received on October 21st.