Anatomy and ontogenetic changes of the facial and gular musculature of the tetraAstyanax brucutu: A remarkable case of adaptation to durophagy

Autor(es)

Vita, George ^{[1, 2]} ; Zanata, Angela Maria ^[1] ; Datovo, Alessio ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Bahia, Inst Biol, Salvador, BA - Brazil

^[2] Univ Sao Paulo, Lab Ictiol, Museu Zool, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Anatomy; v. 237, n. 6 JUL 2020.
• Citações Web of Science: 0

Resumo

Astyanax brucutuis a peculiar species of Neotropical tetra endemic from the Chapada Diamantina, a large plateau in northeastern Brazil. Individuals of this species undergo a dramatic ontogenetic shift in their diet that is accompanied by equally remarkable changes in their feeding apparatus. Whereas juveniles ofA. brucutufeed mostly on algae, adults feed almost exclusively on an endemic species of hydrobiid snail and other associated living organisms that inhabit their dead shells (including infaunal invertebrates and algae). Skeletal adaptations associated with this change in diet were previously reported, but until now, the changes in the musculature remained mostly unknown. The present paper describes the facial and gular muscles, as well as the buccal ligaments ofA. brucutuin different life stages, and identifies the major ontogenetic changes in these systems associated with the diet shift in the species. Such changes primarily involve expansions of specific portions of theadductor mandibulaeand associated tendons and ligaments that likely represent adaptations to increase the biting power necessary to crush copious amounts of shells ingested by larger individuals ofA. brucutu. Those adaptations are absent in specimens of any size ofAstyanaxcf.fasciatus, a sympatric congener lacking durophagous feeding habits. Anatomical comparisons and landmark-based principal components analysis (PCA) suggest that most specializations to durophagy inA. brucutuarose by peramorphosis. We also found that several of the muscular specializations of adults ofA. brucutuare paralleled in species ofCreagrutusandPiabina, two other characid genera distantly related toAstyanax, but that also feed on hard food items. (AU)

• Processo FAPESP: 17/09321-5 - Characiformes miniaturas (Teleostei: Ostariophysi): evolução, diversidade e biogeografia
• Beneficiário: Manoela Maria Marinho Koh
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Jovens Pesquisadores
• Processo FAPESP: 16/19075-9 - Diversidade e evolução de Gymnotiformes (Teleostei, Ostariophysi)
• Beneficiário: Naercio Aquino Menezes
• Modalidade de apoio: Auxílio à Pesquisa - Temático