The Application of Dental Complexity Metrics on Extant Saurians

Melstrom, Keegan M.; Wistort, Zackery P.

doi:10.1655/herpetologica-d-21-00002.1

Cited by 8 publications

(14 citation statements)

References 22 publications

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“…Pineda‐Munoz et al (2017) compared OPCr values for the dentition of 134 extant terrestrial mammals and found that OPCr could easily determine whether a species was carnivorous, but struggled to resolve more specific dietary categories. Melstrom and Wistort (2021) had similar results using a dataset of both squamates and crocodilians, but found that the distinction between carnivores and herbivores varied when using different methods of measuring OPCr. Analysis of dental complexity in the horse lineage by Evans and Janis (2014) showed that horse teeth tended towards higher complexity as later members of the clade became more specialized grazers.…”

Section: Introductionmentioning

confidence: 84%

“…removing half of the model, from the labial-most point inward to the center-line of the mesh. The editing process corrected artifacts that may still have been present and maintained consistency between this project and OPCr analyses of teeth, which typically focus on a single tooth row (i.e., half of the triturating surface is analogous to a single tooth row) (Evans & Janis, 2014;Melstrom & Wistort, 2021;Pineda-Munoz et al, 2017;Santana et al, 2011). Finally, the mesh was downsampled to 5,000 faces, forcing meshes made from larger specimens and meshes made from smaller specimens to show roughly the same level of definition.…”

Section: Mesh Creationmentioning

confidence: 99%

“…Teeth are highly functional tools that have evolved into specialized shapes in many vertebrate taxa, and there is a strong relationship between the shapes of an animal's teeth and its diet (Santana et al, 2011;Pineda-Munoz et al, 2017;Melstrom & Wistort, 2021). The increasing availability of highly accurate 3D (three-dimensional) morphological data has led to major advances in quantitative comparisons of tooth morphology, including the basis of this study: dental topographic analysis (DTA).…”

Section: Introductionmentioning

confidence: 99%

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The topography of diet: Orientation patch count predicts diet in turtles

Shipps

Peecook

Angielczyk

2022

The Anatomical Record

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Use of quantitative morphological methods in biology has increased with the availability of 3D digital data. Rotated orientation patch count (OPCr) leverages such data to quantify the complexity of an animal's feeding surface, and has previously been used to analyze how tooth complexity signals diet in squamates, crocodilians, and mammals. These studies show a strong correlation between dental complexity and diet. However, dietary prediction using this technique has not been tested on the feeding structures of edentulous (toothless) taxa. This study is the first to test the applicability of OPCr to the triturating surface morphology of a beaked clade. Fifty‐five turtle specimens, 42 of which preserved both the skull and rhamphotheca, were categorized into dietary categories based on the food sources comprising 90% or 60% of their diets. Photogrammetric models of each specimen were read into molaR, producing OPCr results. Comparison of bone and rhamphotheca OPCr values shows no significant difference in complexity, implying that bone can suffice for predicting diet from morphology when keratin is absent. Carnivorous taxa have significantly lower OPCr values than herbivorous or omnivorous taxa, showing that feeding surface complexity in edentulous animals varies with diet similarly to tooth complexity in toothed taxa. Comparison of bone OPCr values by family shows that Testudinidae (tortoises) are more complex than Cheloniidae (sea turtles) and Chelydridae (snapping turtles), but that Cheloniidae and Chelydridae are not significantly different from each other. We therefore find that OPCr can be used to differentiate between carnivores and other dietary categories in edentulous taxa.

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Section: Introductionmentioning

confidence: 84%

Section: Mesh Creationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The topography of diet: Orientation patch count predicts diet in turtles

Shipps

Peecook

Angielczyk

2022

The Anatomical Record

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“…The past two decades have seen a surge in quantitative methods for quantifying tooth morphology, especially with regards to reptile teeth, such as 2D/3D geometric morphometrics [ 56 , 61 , 62 ], OPCR [ 25 , 63 ], and nMDS [ 14 ] (see below). The PCA plots visualize overall trends in shape variation among the entire sample of teeth.…”

Section: Discussionmentioning

confidence: 99%

A diverse diapsid tooth assemblage from the Early Triassic (Driefontein locality, South Africa) records the recovery of diapsids following the end-Permian mass extinction

2023

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Mass extinctions change the trajectory of evolution and restructure ecosystems. The largest mass extinction, the end-Permian, is a particularly interesting case due to the hypothesized delay in the recovery of global ecosystems, where total trophic level recovery is not thought to have occurred until 5–9 million years after the extinction event. Diapsids, especially archosauromorphs, play an important role in this recovery, filling niches left vacant by therapsids and anapsids. However, the nature of lineage and ecological diversification of diapsids is obscured by the limited number of continuous, well-dated stratigraphic sections at the Permian-Triassic boundary and continuing through the first half of the Triassic. The Karoo Basin of South Africa is one such record, and particularly the late Early Triassic (Olenekian) Driefontein locality fills this gap in the diapsid fossil record. We collected a total of 102 teeth of which 81 are identified as diapsids and the remaining 21 as identified as temnospondyls. From the sample, seven distinct tooth morphotypes of diapsids are recognized, six of which are new to the locality. We used a combination of linear measurements, 3D geomorphometrics, and nMDS ordination to compare these morphotypes and made inferences about their possible diets. Although the morphotypes are readily differentiated in nMDS, the overall morphological disparity is low, and we infer five morphotypes are faunivorous with the other two potentially omnivorous or piscivorous based on their morphological similarities with dentitions from extant diapsids, demonstrating an unsampled taxonomic and ecological diversity of diapsids in the Early Triassic based on teeth. Although ecological specialization at Driefontein may be low, it records a diversity of diapsid taxa, specifically of archosauromorph lineages.

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“…Decimation reduces triangle count. Many topographic metrics are sensitive to triangle count and require triangle count to be held constant (Berthaume et al, 2019b; Melstrom & Wistort, 2021; Spradley et al, 2017). Only programs with decimation tools which simplified surfaces to a constant triangle count in a single step were considered, as iterative reductions in triangle count can create final surfaces with slight variations in final vertex number and position.…”

Section: Methodsmentioning

confidence: 99%

Technical note: A freeware, equitable approach to dental topographic analysis

Morley

Berthaume

2023

American Journal of Biological Anthropology

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Dental topographic analysis has proved a valuable tool for quantifying dental morphology. Established workflows often use proprietary software for pre‐processing dental surfaces, rendering the method expensive and inaccessible to many. This study explores the use of freeware pre‐processing alternatives. We tested 4 decimation tools and 13 smoothing tools across 7 different freeware packages. Surfaces generated via proprietary software could not be replicated, but it was possible to obtain statistically similar measurements using freeware. Based on this investigation, we propose a freeware workflow for researchers to conduct dental topographic analysis, with the expectation that their results will be comparable to that obtained through proprietary methods.

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The Application of Dental Complexity Metrics on Extant Saurians

Cited by 8 publications

References 22 publications

The topography of diet: Orientation patch count predicts diet in turtles

The topography of diet: Orientation patch count predicts diet in turtles

A diverse diapsid tooth assemblage from the Early Triassic (Driefontein locality, South Africa) records the recovery of diapsids following the end-Permian mass extinction

Technical note: A freeware, equitable approach to dental topographic analysis

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