Cranial osteology and preliminary phylogenetic assessment of Plectrurus aureus Beddome, 1880 (Squamata: Serpentes: Uropeltidae)

Abstract

Uropeltid snakes are among the most poorly understood clades within Alethinophidia. Their small size, limited geographic distribution, high incidence of endemism, and fossorial behaviour all contribute to the general paucity of systematic collections of these snakes, especially of adequate skeletal preparations, in most museum collections. Their hypothesized position within the higher-order phylogeny of alethinophidian snakes calls attention to the need for additional morphological work on the group. Hypotheses of uropeltid phylogenetic relationships based on morphological analyses are few, and continue to be hampered by limited taxon-sampling and character matrices that rely predominantly on features that are visible on articulated skulls. We utilized high-resolution X-ray computed tomography (HRCT) to investigate the cranial osteology of Plectrurus aureus Beddome, 1880, a species for which no osteological data were previously available. We provide a detailed description of the skull and mandible, and comment on morphological characters and potential phylogenetic relationships. Clarity in character descriptions is of paramount importance, and additional morphological characters are desirable. HRCT provides a nondestructive way to identify new systematically informative morphological characters from digitally disarticulated specimens. The small size of many uropeltid species, including P. aureus, will help to frame a greater appreciation of the limitations of traditional HRCT protocols for revealing detailed anatomical features of small vertebrates. © 2010 The Linnean Society of London.