Cranial and postcranial osteology of Apostolepis sanctaeritae Werner, 1924 (Elapomorphini, Dipsadidae, Squamata) with an analysis of intraspecific variation

• Grant number: 24/20552-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: May 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Morphology of Recent Groups
• Principal Investigator: Pedro Pereira Rizzato
• Grantee: Pedro Scivittaro Fontana
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Elapomorphini is a clade of Neotropical snakes that includes at least four genera, whose species occur from the Guianas to Patagonia. The tribe's most diverse genus is Apostolepis, with about 35 species currently recognized. Besides being historically contentious from the taxonomic perspective, several of its species are known from a small number of specimens, so that knowledge not only about its taxonomy, but also morphology and distribution, remain incipient. Apostolepis sanctaeritae is an example: the species has already been synonymized and revalidated several times since its original description. One description of the holotype's skull and jaw is available in the literature, but the post-cranium remains completely unknown. Furthermore, data regarding intraspecific variation in this species, whether ontogenetic or sexual, is not available for the skull or the post-cranium. Since osteological characters, especially those concerning intraspecific variation, can be relevant to the resolution of taxonomic controversies, including species delimitation, the aim of this work is to describe in detail the skull, jaw and post-cranium of A. sanctaeritae, using microCT and cleared and stained specimens. The results, in addition to complementing the information available on the skull and providing the first descriptive study of the post-cranium of A. sanctaeritae, will allow evaluating the intraspecific variation in the skeleton, whether quantitative or qualitative, which will be very useful to future taxonomic studies of the species and the genus.