Comparative dental morphology in sympatric Bornean Eutropis (Squamata: Sauria: Scincidae)

Abstract

Scincidae is a speciose squamate family that is both ecologically diverse and near- cosmopolitan in distribution. The osteology of Scincidae, and particularly the dentition, remains understudied. The tooth morphology of three sympatric skink species of the genus Eutropis (E. multifasciata, E. rudis and E. rugifera), collected from Kota Samarahan, western Sarawak (Borneo), was studied using scanning electron microscopy (SEM). The primary aim was to compare gross tooth as well as fine surface morphology, and to determine possible adaptive suites vis-à-vis their respective diets. Lizards were collected during visual encounter surveys, through the use of adhesive traps, then euthanised and decapitated. Following standard protocol, the maxilla, the mandible and the palatine region were prepared using an ethanol series, critically point-dried and examined under an electron microscope. To determine the possible functions of dental features, implements used in cutting and breaking (scalpel blades, knives and drills) tools were standardised according to the literature. Inter-specific variation in tooth structure was observed, suggesting that blade-like and drill-bit forms function to reduce food bolus size through slicing and drilling, respectively. Comparisons with scalpel blade ridges and edges of commercial drills with dentitional structures, particularly on occlusal surfaces, provide examples of an interdisciplinary approach to understanding the functional application of tooth morphology and its potential for inspiring biologically informed product design.