Reassessment of Tantilla boipiranga (Serpentes: Colubrinae) and a preliminary approach to the phylogenetic affinities within Tantilla

Author(s)

Azevedo, Weverton dos Santos ^{[1, 2]} ; Franco, Francisco Luis ^[1] ; Thomassen, Hans ^[3] ; de Castro, Thiago Marcial ^[4] ; Abegg, Arthur Diesel ^{[1, 2]} ; Leite, Felipe Sa Fortes ^[3] ; Battilana, Jaqueline ^[5] ; Grazziotin, Felipe Gobbi ^[1]

Affiliation

^[1] Inst Butantan, Lab Colecoes Zool, Av Vital Brasil 1500, BR-05503900 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Zool, Programa Posgrad Zool, Travessa 14, Rua Matao 321, Cidade Univ, BR-05508090 Sao Paulo, SP - Brazil

^[3] Univ Fed Vicosa, Inst Ciencias Biol & Saude, Lab Sagarana, BR-35690000 Florestal, MG - Brazil

^[4] Ctr Univ Sao Camilo, Rua Sao Camilo de Lellis 1, BR-29304910 Espirito Santo, ES - Brazil

^[5] Univ Sao Paulo, Lab Biol Mol, Museu Zool, Av Nazare 481, BR-04263000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: SALAMANDRA; v. 57, n. 3, p. 400-412, AUG 15 2021.
• Web of Science Citations: 0

Abstract

Tantilla is one of the most diverse genera among colubrids, with 67 species arranged in six phenotypically recognized species groups. Tantilla boipiranga is the most recently described species within the T. melanocephala group, and it was described based on a small type series, collected in the rupestrian grasslands of south-eastern Brazil. The morphological diversity and the phylogenetic affinity of this species remain poorly known. Here, based on the assessment of recently collected specimens in combination with results of a molecular phylogenetic analysis, we evaluate the morphological variation within T. boipiranga and its phylogenetic position. Our analyses confirm T. boipiranga as genetically distinct from its generic counterparts, and diagnosable based on a combination of colour pattern, meristic counts, and hemipenial morphology. However, contrary to its original description, the hemipenial ornamentation does not differentiate T. boipiranga from the highly variable T. melanocephala. In our phylogenetic analysis, T. boipiranga is retrieved as a monophyletic group, nested within the diversity of T. melanocephala and sister to a clade composed by specimens from south-eastern Brazil. Tantilla melanocephala is recovered as a highly diverse lineage, indicating the possible presence of undescribed species. Additionally, our analysis indicates that the T. coronata and T. planiceps species group are monophyletic, while the T. taeniata species group is paraphyletic and the only sampled species for the T. calamarina group is nested within the T. melanocephala group. Our results suggest that the phenotypic evolution within the genus is probably more complex than previously recognized, and some colouration patterns used to define the groups can in fact represent phenotypical convergences. Moreover, our phylogenetic analysis suggests a strong signal of geographical structure in the tree topology. Three main geographical lineages were found, a North American, a South American and a Central American. The first two lineages were recovered as monophyletic, while the latter is paraphyletic, with Central American species positioned as sister groups of both, the North American and the South American clades. Although a more comprehensive phylogenetic analysis is needed, our study strongly indicates the existence of hidden diversity within the T. melanocephala group and that Tantilla represents an ideal model to evaluate the validity of phenotypical groups in snake systematics and to study the driven mechanisms of morphological evolution. (AU)

• FAPESP's process: 16/50127-5 - Dimensions US-BIOTA São Paulo: scales of biodiversity: integrated studies of snake venom evolution and function across multiple levels of diversity
• Grantee: Inácio de Loiola Meirelles Junqueira de Azevedo
• Support type: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 19/03587-9 - Scales of biodiversity: integrated studies of snake venom evolution and function across multiple levels of diversity
• Grantee: Weverton dos Santos Azevedo
• Support type: Scholarships in Brazil - Technical Training Program - Technical Training