Caudal musculature in ground sharks, Carcharhiniformes, with remarks on their phylogenetic interrelationships

Autor(es)

de Oliveira, Lucas Romero ^[1] ; de Carvalho, Marcelo Rodrigues ^[1] ; Soares, Mateus Costa ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biociencias, Dept Zool, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Morphology; v. 280, n. 1, p. 68-77, JAN 2019.
• Citações Web of Science: 0

Resumo

Relationships among families of the shark order Carcharhiniformes are still being debated, for example, in relation to the inclusion of hammerhead sharks (Sphyrnidae) and the tiger shark (Galeocerdo cuvier) in the Carcharhinidae. Previous morphological studies have not analyzed the phylogenetic significance of axial caudal muscles among carcharhiniforms. The authors therefore describe here the axial muscles of the tail region (m. epaxialis, m. obliquus superioris, m. obliquus inferioris, m. flexor caudalis) to better understand their anatomical patterns among carcharhiniform sharks. Our results indicate that the family Pentanchidae, recently separated from scyliorhinids (catsharks), present a similar pattern of caudal muscles to catsharks, indicating their close phylogenetic relationship. Triakids, hemigaleids, leptochariids, Galeocerdo cuvier and Prionace glauca have a unique pattern in which the medial axial bundle is bulkier than all other caudal axial muscles. Sphyrnids share with carcharhinids a similar pattern of the m. obliquus superioris (approximately the same size as the dorsal m. epaxialis) and have fibers of the m. flexor caudalis arranged in a V-shape. This chevron-shape is also present on the m. flexor caudalis of hemigaleids and leptochariids. Also, sphyrnids and carcharhinids have more slender septa between muscle bundles (more notably in carcharhinids; the only exception is Galeocerdo cuvier, which has the same pattern as sphyrnids). Although being used here as an outgroup, Squaliformes is unique in lacking one of the epaxial bundles. The authors conclude that the caudal axial musculature has greater phylogenetic potential than previously understood. (AU)

• Processo FAPESP: 14/13023-1 - Anatomia e padrões evolutivos da musculatura caudal em Carcharhinidae (Carcharhiniformes:Chondrichthyes)
• Beneficiário: Lucas Romero de Oliveira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica