Phylogenetic interrelationships, taxonomy, and reductive evolution in the Neotropical electric fish genus Hypopygus (Teleostei, Ostariophysi, Gymnotiformes)

Authors

  • CARLOS D. DE SANTANA,

    1. University of Central Florida, Department of Biology, Orlando, FL, 32816-2368, USA
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    • Museu Paraense Emílio Goeldi, Av. Magalhães Barata 376, Cx. Postal 399, 66040-170 Belém, PA, Brazil.

  • WILLIAM G. R. CRAMPTON

    Corresponding author
    1. University of Central Florida, Department of Biology, Orlando, FL, 32816-2368, USA
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E-mail: crampton@mail.ucf.edu

Abstract

A phylogenetic reconstruction of the Neotropical electric fish genus Hypopygus based on 47 parsimony-informative morphological characters is presented. A series of synapomorphies support the hypothesis of monophyly of Hypopygus, and partially resolve species-level relationships within the genus. Hypopygus species are recognized here as miniaturized fishes based on two criteria; first, a derived condition of diminutive body size, and; second, the presence of a suite of reductive morphological characters, including partial or total losses, simplifications, and reductions of the anal-fin rays, scales, cranial bones, and laterosensory canal system. Reductive characters associated with miniaturization comprise 45% of the total number of characters in the phylogenetic reconstruction of the genus. Miniaturization and reductive morphological evolution in Hypopygus are discussed here in the phylogenetic context. A taxonomic revision of Hypopygus is presented, in which five new species are described, two species previously assigned to the genus are redescribed, and a single known species of Stegostenopos is redescribed and included in Hypopygus as a junior synonym. Distribution maps and a key for all eight valid species of Hypopygus are provided, based on the examination of 5014 catalogued museum specimens.

© 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, 1096–1156.

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