Bestwick Jordan, Unwin David M, Henderson Donald M, Purnell Mark A
School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Centre for Palaeobiology Research, School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK.
R Soc Open Sci. 2021 Feb 3;8(2):201754. doi: 10.1098/rsos.201754.
Dental microwear texture analysis (DMTA) is a powerful technique for reconstructing the diets of extant and extinct taxa. Few studies have investigated intraspecific microwear differences along with tooth rows and the influence of endogenous non-dietary variables on texture characteristics. Sampling teeth that are minimally affected by non-dietary variables is vital for robust dietary reconstructions, especially for taxa with non-occlusal (non-chewing) dentitions as no standardized sampling strategies currently exist. Here, we apply DMTA to 13 species of extant reptile (crocodilians and monitor lizards) to investigate intraspecific microwear differences along with tooth rows and to explore the influence of three non-dietary variables on exhibited differences: (i) tooth position, (ii) mechanical advantage, and (iii) tooth aspect ratio. Five species exhibited intraspecific microwear differences. In several crocodilians, the distally positioned teeth exhibited the 'roughest' textures, and texture characteristics correlated with all non-dietary variables. By contrast, the mesial teeth of the roughneck monitor () exhibited the 'roughest' textures, and texture characteristics did not correlate with aspect ratio. These results are somewhat consistent with how reptiles preferentially use their teeth during feeding. We argue that DMTA has the potential to track mechanical and behavioural differences in tooth use which should be taken into consideration in future dietary reconstructions.
牙齿微磨损纹理分析（DMTA）是一种用于重建现存和已灭绝分类群饮食结构的强大技术。很少有研究调查沿齿列的种内微磨损差异以及内源性非饮食变量对纹理特征的影响。对于可靠的饮食重建而言，采样受非饮食变量影响最小的牙齿至关重要，特别是对于具有非咬合（非咀嚼）齿列的分类群，因为目前不存在标准化的采样策略。在此，我们将DMTA应用于13种现存爬行动物（鳄鱼和巨蜥），以研究沿齿列的种内微磨损差异，并探讨三个非饮食变量对所表现出差异的影响：（i）牙齿位置，（ii）机械优势，以及（iii）牙齿长宽比。五个物种表现出种内微磨损差异。在几种鳄鱼中，位于远端的牙齿表现出“最粗糙”的纹理，并且纹理特征与所有非饮食变量相关。相比之下，粗颈巨蜥（）的近端牙齿表现出“最粗糙”的纹理，并且纹理特征与长宽比不相关。这些结果在一定程度上与爬行动物在进食过程中优先使用牙齿的方式一致。我们认为DMTA有潜力追踪牙齿使用方面的机械和行为差异，而这在未来的饮食重建中应予以考虑。
