[dinosaur] Theropod dental features: taxonomic potential, evolutionary trends (free pdf)

Ben Creisler
[email protected]

A new paper in open access:

Christophe Hendrickx, Octávio Mateus, Ricardo Araújo, and Jonah Choiniere
(2019)
The distribution of dental features in non-avian theropod dinosaurs:
Taxonomic potential, degree of homoplasy, and major evolutionary trends.
Palaeontologia Electronica 22.3.74: 1–110
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.26879_820&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XpUP6HzClkIVWyx5qn34lx8h782XWGtlNbMok8Q4S38&s=6NbChrXr40SqyvLQpLAn5iDcC7LTbs0EtmRopRSTS_c&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__palaeo-2Delectronica.org_content_2019_2806-2Ddental-2Dfeatures-2Din-2Dtheropods&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XpUP6HzClkIVWyx5qn34lx8h782XWGtlNbMok8Q4S38&s=M1QBR9Cz_AyyiY_nu7TAHJf_tN_owJ77pZnNx6gDi1Q&e= 

Free pdf:
https://urldefense.proofpoint.com/v2/url?u=https-3A__palaeo-2Delectronica.org_content_pdfs_820.pdf&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=XpUP6HzClkIVWyx5qn34lx8h782XWGtlNbMok8Q4S38&s=2o4wwSp3h6sueiUkY4W7jWKDmzPbBZvEJu0XsgfLzAo&e= 


Isolated theropod teeth are some of the most common fossils in the dinosaur
fossil record and are continually reported in the literature. Recently
developed quantitative methods have improved our ability to test the
affinities of isolated teeth in a repeatable framework. But in most
studies, teeth are diagnosed on qualitative characters. This can be
problematic because the distribution of theropod dental characters is still
poorly documented, and often restricted to one lineage. To help in the
identification of isolated theropod teeth, and to more rigorously evaluate
their taxonomic and phylogenetic potential, we evaluated dental features in
two ways. We first analyzed the distribution of 34 qualitative dental
characters in a broad sample of taxa. Functional properties for each dental
feature were included to assess how functional similarity generates
homoplasy. We then compiled a quantitative data matrix of 145 dental
characters for 97 saurischian taxa. The latter was used to assess the
degree of homoplasy of qualitative dental characters, address longstanding
questions on the taxonomic and biostratigraphic value of theropod teeth,
and explore the major evolutionary trends in the theropod dentition.

In smaller phylogenetic datasets for Theropoda, dental characters exhibit
higher levels of homoplasy than non-dental characters, yet they still
provide useful grouping information and optimize as local synapomorphies of
smaller clades. In broader phylogenetic datasets, the degree of homoplasy
displayed by dental and non-dental characters is not significantly
different. Dental features on crown ornamentations, enamel texture and
tooth microstructure have significantly less homoplasy than other dental
features and can be used to identify many theropod taxa to ‘family’ or
‘sub-family’ level, and some taxa to genus or species. These features
should, therefore, be a priority for investigations seeking to classify
isolated teeth.

Our observations improve the taxonomic utility of theropod teeth and in
some cases can help make isolated teeth useful as biostratigraphic markers.
This proposed list of dental features in theropods should, therefore,
facilitate future studies on the systematic paleontology of isolated teeth.