Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
J Morphol. 2021 Mar;282(3):438-448. doi: 10.1002/jmor.21315. Epub 2021 Jan 9.
Torpediniformes (electric rays) is a monophyletic group strongly supported by morphological and molecular phylogenetic studies. The claspers of electric rays, however, are poorly documented in comparation to the clasper of other batoids, especially skates, and the knowledge of their anatomical variation is restricted to the description of a few species. The present article analyzes the external and skeletal clasper anatomy of electric rays and reports newly discovered characters that can be useful for taxonomic diagnoses and higher-level systematic studies. The family Torpedinidae exclusively presents the integumental flap, a poorly calcified clasper skeleton, and a dorsal marginal cartilage with a medial flange on its distal portion. Derived or diagnostic characters were not found in the clasper of the reportedly nonmonophyletic families Narcinidae and Narkidae; however, the claspers of species and genera of narcinids and narkids present different anatomical patterns that can be useful for taxonomic and phylogenetic studies.
电鳐目（电鳐）是一个单系群，得到了形态学和分子系统发育研究的强烈支持。然而，与其他鳐形目动物（尤其是鳐）的鳍脚相比，电鳐的鳍脚记录很差，其解剖变异的知识仅限于少数几种物种的描述。本文分析了电鳐的外部和骨骼鳍脚解剖结构，并报告了新发现的特征，这些特征对于分类诊断和高级系统发育研究可能有用。电鳐科仅具有表皮瓣、骨骼鳍脚的钙化程度低以及背缘软骨在其远端具有内侧凸缘。在据称非单系的 Narcinidae 和 Narkidae 科的鳍脚中没有发现衍生或诊断特征；然而，narci-nid 和 narkid 属种的鳍脚具有不同的解剖结构，这些结构对于分类和系统发育研究可能有用。
