Taxonomy and phylogenetic systematics of the species complex Tantilla melanocephala (Serpentes: Colubridae): investigating biogeographic patterns, unraveling evolutionary processes

• Grant number: 24/15082-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: December 01, 2024
• End date: December 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Felipe Gobbi Grazziotin
• Grantee: Weverton dos Santos Azevedo
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 22/12660-4 - Recovering, modernizing and expanding the collection of herpetology at Butantan Institute through integrative studies on systematics and evolution of neotropical snakes, AP.BTA.JP

Abstract

After 266 years since the publication of the 10th edition of Linnaeus's Systema Naturae (1758), the taxonomic history of the snake species Tantilla melanocephala remains a controversial topic. The taxonomic identity and phylogenetic affinities of its populations are unclear and point to the existence of an undescribed species complex. In this doctoral project, our objectives are: (1) identify the hidden diversity within the Tantilla melanocephala species complex; (2) infer the phylogenetic relationships among the species within this complex; (3) understand the biogeographic patterns of these species; (4) infer the evolutionary processes that shaped their phenotypic variability; and (5) characterize the transcriptome of their venom glands. To achieve these objectives, we adopt an integrated approach that combines varied methodologies to analyze a broad set of morphological and molecular evidence. We will also employ historical DNA extraction methods to sequence the type specimens available for the synonyms of T. melanocephala, enabling the identification of associations between these specimens and potential new species within the complex. We will analyze the final data set through six analytical approaches: (1) comparative morphological analyses; (2) assessment of the phylogeographic structure of populations; (3) phylogenetic analyses; (4) estimation of divergence times of the main lineages within the complex; (5) historical biogeographic analyses; and (6) transcriptome analyses of venom glands. At the end of this project, we expect to unravel the intricate taxonomic and evolutionary scenario of the T. melanocephala complex, contributing to the understanding of the evolutionary processes and biogeographic patterns that have generated South American biodiversity.