J Syst Evol

• Research Article •    

Almost half of the Gymnura van Hasselt, 1823 species are unknown: Phylogeographic inference as scissors for cutting the hidden Gordian knot and clarify their conservation status

Suellen M. Gales1, Kristene T. Parsons2, Ellen E. Biesack3, Jonathan Ready1, Raquel Siccha-Ramirez4, Leonardo C. Rosa5, Ricardo Rosa6, Matheus M. Rotundo7, Roger Bills8, Alan Erik S. Rodrigues1, Luis Fernando S. Rodrigues-Filho9, Jan McDowell3, and João Bráullio L. Sales1*   

  1. 1 Biological Institute of Sciences, Laboratory of Aquatic Molecular Biology, Center for Advanced Biodiversity Studies(CEABIO), Federal University of Pará, Av. Perimetral da Ciência, km 01, PCT-Guamá, Lot 11, Belém 66075-750, PA, Brazil;
    2 Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 2796 Overseas Highway, Marathon 33050, FL, USA;
    3 Virginia Institute of Marine Science, College of William and Mary, Gloucester Point 23062, VA, USA;
    4 Laboratorio de Genómica y bioinformática para la biodiversidad, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Perú;
    5 Department of Fishery Engineering and Aquaculture(DEPAq), Laboratory of Benthic Ecology, Center for Applied Agrarian Sciences(CCAA), Federal University of Sergipe, São Cristovão, SE, Brazil;
    6 Department of Systematics and Ecology, CCEN, Federal University of Paraíba, João Pessoa 58051-900, PB, Brazil;
    7 Zoological Collection at Santa Cecília University(AZUSC), Graduate and postgraduate in Marine Biology(Biodiversity), Santa Cecília University, 258 Oswaldo Cruz Street, Boqueirão, Santos ZIP 11045-307, SP, Brazil;
    8 South African Institute for Aquatic Biodiversity, Grahamstown 6140, South Africa;
    9 Department of Biological Science, Federal Rural University of Amazônia, Graduate Course in Biological Sciences, Capanema Campus, Capanema ZIP 68600-030, PA, Brazil
    *Author for correspondence. E-mail:braullio@ufpa.br
  • Received:2023-04-25 Accepted:2023-09-01 Online:2023-11-05

Abstract: Gymnurid rays are found in tropical, subtropical, and temperate regions around the world, where they are associated with sandy or muddy bottoms in coastal areas, being easily distinguished from other rays by the width of the disc. In recent years, the systematics of this family have been revised extensively. However, there has been no comprehensive molecular review of the family based on an adequate sample of species and localities, which may have obscured the presence of distinct evolutionary lineages. The present study was based on samples of 12 of the 13 valid species of the genus Gymnura, which were used for a multilocus reconstruction of the evolutionary history of the family Gymnuridae. Our results indicate the existence of several cryptic gymnurid lineages, within the species Gymnura micrura, Gymnura lessae, Gymnura altavela, and Gymnura poecilura. Also, we indicate that only half of the species that compose the genus are known, as well their conservation status. The analyses also indicate that the gymnurids originated during the Paleocene, with events of dispersal and vicariance occurring through the formation of oceanographic barriers, and species diversification peaking during the Oligocene and Miocene. The results of the present study reinforce the need for a comprehensive revision of the systematics of the family, in particular, the widely distributed species that are considered valid taxa, but may, in fact, represent different cryptic species. The inadequate classification of this cryptic diversity may have negative implications for the development of effective conservation measures.

Key words: blue Amazon, butterfly rays, cryptic speciation, evolutionary history