Taxonomic and morphological revision of the Family Squalidae Blainville, 1816 (Elasmobranchii: Chondrichthyes: Squaliformes)

Author(s)

Sarah Tházia Viana de Figueirêdo

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2016-03-24

Examining board members

Marcelo Rodrigues de Carvalho; Ulisses Leite Gomes; Naercio Aquino Menezes; Mônica de Toledo Piza Ragazzo; Alessio Datovo da Silva

• Advisor: Marcelo Rodrigues de Carvalho

Abstract

Squalidae comprises two genera of sharks, Cirrhigaleus Squalus, whose species have complex taxonomy due to difficulty of morphological distinction between them, associated to an uncertainty to the application of its available nominal species. A taxonomic and morphological revision of the family was conducted in order to globally delimitate the valid species and provide efficient diagnostic characters through detailed analyses of external and skeletal morphology. Squalus is herein recognized as a smaller group, which comprises three species of spotted-dogfish. A second genus is raised as separated from Squalus with 27 species of non-spotted dogsharks. Thus, the hypothesis of subdivision of Squalus into three groups/complexes of species (S. acanthias, S. mitsukurii and S. megalops groups) is refuted. Seven new species are described for the South Atlantic and West Indian Oceans, and two nominal species are resurrected as valid for the family. Five species are proposed as new synonyms from other species within this context. Cirrhigaleus is a valid and less diverse genus, comprising three species of barbel-bearing dogfish. Generic allocation of the nominal species “asper”, beforehand under constant discussions on literature, is elucidated for Cirrhigaleus. However, taxonomic classification of Cirrhigaleus within Squalidae is questioned and a new family for Squaliformes is proposed to incorporate the genus. Characteristics of the skeleton in Squalidae reveal to be more complex than previously thought. Morphological characters are also provided for integrating future phylogenetic analysis (AU)

• FAPESP's process: 11/18861-7 - Taxonomic and morphological revision of the family Squalidae Blainville, 1816 (Elasmobranchii: Chondrichthyes: Squaliformes)
• Grantee: Sarah Tházia Viana de Figueirêdo
• Support Opportunities: Scholarships in Brazil - Doctorate