Tooth enamel microstructure of Revueltosaurus and Krzyzanowskisaurus (Reptilia: Archosauria) from the Upper Triassic Chinle Group, USA: Implications for function, growth, and phylogeny
- ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
- Andrew B. Heckert Ph.D., Professor (Creator)
- Institution
- Appalachian State University (ASU )
- Web Site: https://library.appstate.edu/
Abstract: Tooth enamel microstructure can carry significant phylogenetic, ontogenetic, and
functional information within amniotes. Here we provide the first descriptions of the
tooth enamel microstructure of two Late Triassic taxa, the crurotarsan Revueltosaurus
callenderi Hunt and the putative ornithischian Krzyzanowskisaurus hunti (Heckert),
which some consider closely related. To test the hypotheses that enamel thickness
corresponds to function and/or phylogeny we analyzed the enamel of each at various
scales, measuring enamel thickness and examining microstructural features throughout
both longitudinal and cross-sectional thickness using previously established techniques
to facilitate comparisons. Both taxa possess thick (up to ~150 µm) enamel for
their size (< 20 mm crown height). Enamel in R. callenderi ranged from ~5-152 µm
across a premaxillary tooth in longitudinal section, and ~42-92 µm in a maxillary/dentary
tooth transverse section. K. hunti enamel thickness was ~18-155 µm longitudinally
and ~29-75 µm transversely. Both also had well-developed basal unit layers (BUL) and
weakly developed columnar microstructure. Well-developed lines of incremental
growth (LIG) are present in both taxa, through which the columnar enamel grades into
parallel crystallite enamel. Their enamel microstructure is therefore grossly similar to
that of several ornithischian taxa, especially ankylosaurs, with which they are strongly
convergent, and also compares well to rauisuchids and tyrannosaurids. The relatively
unique combination of microstructural characteristics in the schmelzmuster of R. callenderi
and K. hunti supports the hypothesis that they are closely related, but does not
conclusively preclude a different taxonomic placement for K. hunti so we retain its separate
generic designation.
Tooth enamel microstructure of Revueltosaurus and Krzyzanowskisaurus (Reptilia: Archosauria) from the Upper Triassic Chinle Group, USA: Implications for function, growth, and phylogeny
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Additional Information
- Publication
- Heckert, A.B., and Miller-Camp, J.A. (2013), Tooth enamel microstructure of Revueltosaurus and Krzyzanowskisaurus (Reptilia: Archosauria) from the Upper Triassic Chinle Group, USA: Implications for function, growth, and phylogeny, Palaeontologia Electronica, 16(1): 1A, 23p. Published by the Society for Vertebrate Paleontology (ISSN: 1998–2013). Available online at: http://palaeo-electronica.org/content/in-press/344-revueltosaurus-tooth-enamel
- Language: English
- Date: 2013