Technical note: Comparing dental topography software using platyrrhine molars.

OBJECTIVES: There remain many idiosyncrasies among the values calculated for varying dental topography metrics arising from differences in software preferences among research groups. The aim of this work is to compare and provide potential conversion formulae for dental topography metrics calculated using differing software platforms. METHODS: Three software packages: ArcGIS, Surfer Manipulator, and molaR were used to calculate orientation patch count rotated (OPCR), Dirichlet normal energy (DNE), occlusal relief (OR), slope (m), and angularity (a) on platyrrhine second upper molars. Values derived from the various software packages were compared for distributional consistency and correlation. Where appropriate, formulae for conversion between like measures calculated on different software platforms were developed. RESULTS: When compared with the same measurement across software, OPCR, OR, and slope were all highly correlated. However, only OR demonstrated distributional consistency (i.e., nearly consistent mean, median, max, and min). Slope and OPCR were both higher when calculated by molaR as compared to Surfer Manipulator and ArcGIS calculations, conversion formulae are provided for these measures. DNE is only weakly correlated with angularity; but is correlated with orientation patch count across taxa. DISCUSSION: We explore why there is variation in the dental topography values calculated among the various software packages. The conversion formulae provided in this work will make possible direct comparisons among studies conducted across multiple research groups.

The relationship between diet and tooth complexity in living dentigerous saurians.

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. I investigated the relationship 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 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 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 herbivorous skinks have relatively simple teeth. In particular, insectivorous lizards have dental complexities that are very similar to omnivores. Regardless, OPCR-values for animals that consume significant amounts of plant material are higher than those of carnivores, with herbivores having the highest average dental complexity. These results suggest reptilian tooth complexity is related to diet, similar to extinct and extant mammals, although phylogenetic history also plays a measurable role in dental complexity. This has implications for extinct amniotes that display a dramatic range of tooth morphologies, many with no modern analogs, which inhibits detailed dietary reconstructions. These data demonstrate that OPCR, when combined with additional morphological data, has the potential to be used to reconstruct the diet of extinct amniotes. J. Morphol. 278:500-522, 2017. © 2017 Wiley Periodicals, Inc.