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Quantifying Saurian Tooth Complexity: Implications for Reconstructing the Diet of Extinct Amniotes Project ID: 00000C217 Public
49 Media · 47 Specimens · Creator: Melstrom, Keegan · Managed by: Keegan Melstrom

Recent paleontological discoveries reveal a dramatic range of tooth morphologies in extinct reptiles, with some dentitions rivaling the complexity of extant mammals. Many of these dental morphologies have no modern analogs, inhibiting detailed dietary and ecological reconstructions for ancient ecosystems. Living saurian reptiles exhibit a wide range of diets, from carnivores to strict herbivores. Previous research suggests that the tooth shape in some lizard clades correlates with diet, but this has not been tested using quantitative methods. In order to elucidate the diet of extinct heterodont reptiles, I investigated the correlation between phenotypic tooth complexity and diet in living reptiles by examining the entire dentary tooth row in over 80 specimens comprising all major dentigerous saurian clades. I quantified dental complexity using orientation patch count rotated (OPCR), which does not require the identification of homologous landmarks on each tooth and discriminates diet in living and extinct mammals, where OPCR values increase with the proportion of dietary plant matter. OPCR was calculated from high-resolution CT scans, and I standardized OPCR values by the total number of teeth to account for differences in tooth count across taxa. In living saurians, OPCR values for omnivores and herbivores are higher than those of carnivores. In contrast with extant mammals, there appears to be greater overlap in tooth complexity values across dietary groups because multicusped teeth characterize herbivores, omnivores, and insectivores, and because the herbivorous skinks have particularly simple teeth. Additionally, insectivorous lizards have dental complexities that overlap with omnivores. These results suggest reptilian tooth complexity is related to diet, similar to extinct and extant mammals.

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  ID Part Object Taxonomy Type Date Added Publication Status  
000012465 Lower jaws cas:herp:42076 Uma scoparia scoparia Mesh 2016-05-07 Restricted Download  
000012461 Lower jaws cas:herp:200862 Sceloporus magister Mesh 2016-05-07 Restricted Download  
000012444 Dentary cas:herp:93242 Plica umbra Mesh 2016-05-06 Restricted Download  
000012414 Dentary cas:herp:Uncatalogued2 Hemitheconyx caudicinctus Mesh 2016-05-05 Restricted Download  
000012401 Mandibles cas:herp:159492 Heloderma suspectum Mesh 2016-05-05 Restricted Download  
000012373 Lower jaws cas:herp:141318 Gambelia sila Mesh 2016-05-05 Restricted Download  
000012357 Lower jaws cas:herp:216644 Elgaria coerulea palmeri Mesh 2016-05-05 Restricted Download  
000012219 Dentary cas:herp:46399 Ctenosaura hemilopha nolascensis Mesh 2016-05-04 Restricted Download  
000012203 Dentary cas:herp:200859 Crotaphytus bicinctores Mesh 2016-05-04 Restricted Download  
000012086 Dentary cas:herp:243761 Calotes mystaceus Mesh 2016-05-02 Restricted Download  
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