Abstract
A new species of Neotropical freshwater stingray, family Potamotrygonidae, is described from the Río Nanay in the upper Río Amazonas basin of Peru. Potamotrygon tigrina, n. sp., is easily distinguished from all congeners by its conspicuous dorsal disc coloration, composed of bright yellow to orange vermiculations strongly interwoven with a dark-brown to deep-black background. Additional features that in combination diagnose P. tigrina, n. sp., include the presence of a single angular cartilage, low and not closely grouped dorsal tail spines, and coloration of tail composed of relatively wide and alternating bands of creamy white and dark brown to black. Potamotrygon tigrina is closely related to Potamotrygon schroederi Fernandez-Yépez, 1958, which occurs in the Rio Negro (Brazil) and Río Orinoco (Venezuela, Colombia). Both species are very similar in proportions and counts, and share features hypothesized to be derived within Potamotrygonidae, related to their specific angular cartilage morphology, distal tail color, dorsal tail-spine pattern, and ventral lateral-line system. To further substantiate the description of P. tigrina, n. sp., we provide a redescription of P. schroederi based on material from the Rio Negro (Brazil) and Río Orinoco (Venezuela). Specimens from the two basins differ in number of vertebral centra and slightly in size and frequency of rosettes on dorsal disc, distinctions that presently do not warrant their specific separation. Potamotrygon tigrina is frequently commercialized in the international aquarium trade but virtually nothing is known of its biology or conservation status.References
Achenbach, G.M. (1967) Notas sobre una nueva especie de raya fluvial (Batoidei, Potamotrygonidae) pescada en el río Colastiné (Paraná medio, Departamento La Capital, Provincia de Santa Fe, Republica Argentina). Comunicaciones del Museo Provincial de Ciencias Naturales Florentino Ameghino, 1, 1–7.
Araújo, M.L.G. de (2004) Potamotrygon schroederi. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucnredlist.org (downloaded on 20 March 2011).
Bigelow, H.B. & Schroeder, W.C. (1953) The Fishes of the Western North Atlantic, Part II: Sawfishes, Skates, Rays and Chimaeroids. Memoirs Sears Foundation for Marine Research, 2, 1–588.
Carvalho, M.R. de & Lovejoy, N.R. (2011) Morphology and phylogenetic relationships of a remarkable new genus and two new species of Neotropical freshwater stingrays from the Amazon basin (Chondrichthyes: Potamotrygonidae). Zootaxa, 2776, 13–48.
Carvalho, M.R. de, Lovejoy, N.R. & Rosa, R.S. (2003) Family Potamotrygonidae. Pp. 22–29. In: Reis, R. E, Ferraris Jr, C. J. & Kullander, S. O. (Eds.). Checklist of the Freshwater Fishes of South and Central America. Porto Alegre, EDIPUCRS, 729p.
Carvalho, M.R. de, Maisey, J.G. & Grande, L. (2004) Freshwater stingrays of the Green River Formation of Wyoming (Early Eocene), with the description of a new genus and species and an analysis of its phylogenetic relationships (Chondrichthyes: Myliobatiformes). Bulletin of the American Museum of Natural History, 284, 1–136.
Castex, M.N. & Yagolkowski, D.R. (1970) Note on two fresh-water sting-rays species (Condrichthyes, Potamotrygonidae): a. Redescription of Potamotrygon schroederi, Yepez 1957. b. Designation of two paratypes of P. pauckei Castex 1963 and their description. Acta Scientifica, Universidad del Salvador, 9, 1–26.
Chu, Y.T. & Wen, C.M. (1979) A study of the lateral-line canals system and that of Lorenzini ampullae and tubules of Elasmobranchiate fishes of China. Monograph of Fishes of China 2. Shanghai, Shanghai Science and Technology Press, 132p.
Compagno, L.J.V. (1999) Checklist of living Chondrichthyes. Pp. 471–498. In: Hamlett, W. C. (Ed.), Sharks, Skates and Rays, the Biology of Elasmobranch Fishes. Baltimore, The John Hopkins Univ. Press, 515p.
Compagno, L.J.V. (2005) Checklist of living Chondrichthyes. Pp. 503–548. In: Hamlett, W. C. (Ed.), Reproductive Biology and Phylogeny of Chondrichthyes, Sharks, Batoids and Chimaeras. Enfield (NH), Science Publishers, Inc., 562p.
Compagno, L.J.V. & Cook, S.F. (1995) The exploitation and conservation of freshwater elasmobranchs: status of taxa and prospects for the future. Pp. 62–90. In: Oetinger, M. I. & Zorzi, G. D. (Eds.), The Biology of Freshwater Elasmobranchs, A Symposium to Honor Thomas B. Thorson. Journal of Aquariculture & Aquatic Sciences, 7, 162p.
Compagno, L.J.V. & Roberts, T. (1982) Freshwater stingrays (Dasyatidae) of southeast Asia and New Guinea, with description of a new species of Himantura and reports of unidentified species. Environmental Biology of Fishes, 7(4), 321–339.
Deynat, P. (2006) Potamotrygon marinae n. sp., une nouvelle espèce de raies d’eau douce de Guyane (Myliobatiformes, Potamotrygonidae). Comptes Rendus Biologies, 329, 483–493.
Dingerkus, G. & Uhler, L.D. (1977) Enzyme clearing of alcian blue stained whole smalle vertebrates for demonstration of cartilage. Stain Technology, 52(4), 229–232.
Duncan, W.P., Inomata, S.O. & Fernandes, M.N. (2010) Comércio de raias de água doce na região do médio Rio Negro, Estado do Amazonas, Brasil. Revista Brasileira de Engenharia de Pesca, 5(2), 13–22.
Ewart, J.C. & Mitchell, H.C. (1892) On the lateral sense organs of elasmobranchs. II. The sensory canals of the common skate (Raja batis). Transactions of the Royal Society of Edinburgh, 37, 87–105.
Fernández-Yépez, A. (1949) Uma interesante raya del Río Orinoco, Venezuela. Contribuiciones Ocasionales de La Colección Ictiológica del Laboratorio de Pesquería Caiguire, 1, 1–12.
Fernández-Yépez, A. (1958) Nueva raya para la ciencia: Potomatrygon [sic] schroederi n. sp. Boletín Museo de Ciencia Natural, 2–3, 8–11.
Garman, S. (1877) On the pelvis and external sexual organs of selachiens, with special reference to the new genera Potamotrygon and Disceus. Proceedings of the Boston Society of Natural History, 19, 197–215.
Garman, S. (1888) On the lateral canal system of the Selachia and Holocephala. Bulletin of the Museum of Comparative Zoology, 17, 57–119.
Garman, S. (1913) The Plagiostomia (sharks, skates and rays). Memoirs of the Museum of Comparative Zoology, 36, xiii + 515p., 77 pls.
Gobbo, R.G. (2006) Importância sistemática da distribuição dos canais ventrais da linha lateral em raias de água doce neotropicais (Chondrichthyes: Myliobatiformes: Potamotrygonidae). Unpubl. Bachelor’s monograph, Universidade de São Paulo, São Paulo, 55p.
Hubbs, C.L. & Ishiyama, R. (1968) Methods for the taxonomic study and description of skates (Rajidae). Copeia, 1968 (3), 483–491.
Lasso, C., Ponte, V. & Lasso-Alcalá, O. (1998) Catálogo de la colección de tipos del Museo de Historia Natural La Salle, Caracas, Venezuela. Memoria Sociedad de Ciencias Naturales La Salle, 57 (147), 37–52.
Lasso, C., Lew, D., Taphorn, D., DoNascimiento, C., Lasso-Alcalá, O., Provenzano, F. & Machado-Allison, A. (2004) Biodiversidad ictiológica continental de Venezuela. Parte I. Lista de especies y distribución por cuencas. Memoria de la Fundación La Salle de Ciencias Naturales, 159–160, 105–195.
Machado-Allison, A., Chernoff, B., Silvera, C., Bonilla, A., López-Rojas, H., Lasso, C.A., Provenzano, F., Marcano, C. & Machado-Aranda, D. (1999) Fish inventory of the Caura river basin, Bolivar state, Venezuela. Acta Biologica Venezuelica, 19 (4), 61–72.
Machado-Allison, A., Chernoff, B., Provenzano, F., Willink, P.W., Marcano, A., Petry, P., Sidlauskas, B. & Jones, T. (2003a) Inventory, Relative Abundance and Importance of Fishes in the Caura River Basin, Bolívar State, Venezuela. Pp. 64–74. In: Chernoff, B., Machado-Allison, A., Riseng, K. & Montambault, J. R. (Eds.), A Biological Assessment of the Aquatic Ecosystems of the Caura River Basin, Bolívar State, Venezuela. RAP Bulletin of Biological Assessment 28. Conservation International, Washington, DC, 284p.
Machado-Allison, A., Chernoff, B., Provenzano, F., Willink, P.W., Marcano, A., Petry, P., Jones, T. & Sidlauskas, B. (2003b) Fishes collected during the AquaRAP expedition to the Caura River Basin, Bolívar State, Venezuela. Pp. 267–275. In: Chernoff, B., Machado-Allison, A., Riseng, K. & Montambault, J. R. (Eds.), A Biological Assessment of the Aquatic Ecosystems of the Caura River Basin, Bolívar State, Venezuela. RAP Bulletin of Biological Assessment 28. Conservation International, Washington, DC, 284p.
Mago-Leccia, F. (1970) Lista de los peces de Venezuela, incluyendo un estudio preliminar de la ictiogeografía del país. Ministerio de Agricultura y Cría, Caracas, 285p.
Mago-Leccia, F. (1978) Los Peces de Agua Dulce de Venezuela. Cuadernos Lagoven, Caracas. 36p.
Maldonado-Ocampo, J.A., Vari, R.P. & Usma, J.S. (2008) Checklist of the freshwater fishes of Colombia. Biota Colombiana 9 (2), 143–237.
Mejia-Falla, P.A., Navia, A.F., Mejia-Ladino, L.M., Acero, A. & Rubio, E.A. (2007) Tiburones y rayas de Colombia (Pisces Elasmobranchii): lista actualizada, revisada y comentada. Boletin de Investigaciones Marinas y Costeras, 36, 111–149.
Rosa, R.S. (1985) A systematic revision of the South American freshwater stingrays (Chondrichthyes: Potamotrygonidae). Unpublished PhD diss., College of William and Mary, Williamsburg, xvi + 523p.
Rosa, R.S. & Carvalho, M.R. de (2007) Família Potamotrygonidae. Pp. 17–18. In: Buckup, P. A., Menezes, N. A. & Ghazzi, M. S. (Org.). Catálogo das espécies de peixes de água doce do Brasil. Rio de Janeiro, Museu Nacional, 195p.
Rosa, R.S., Charvet-Almeida, P. & Quijada, C.C.D. (2010) Biology of the South American potamotrygonid stingrays. Pp. 241–281. In: Carrier, J. C., Musick, J. A. & Heithaus, M. R. (Eds.), Sharks and Their Relativies II: Biodiversity, Adaptative Physiology, and Conservation. CRC Press, Florida, 736p.
Ross, R.A. & Schäfer, F. (2000) Aqualog Süsswasser Rochen: Freshwater Rays. Verlag ACS, Mörfelden-Walldorf, 192p.
Silva, J.P.C.B. da (2010) Revisão taxonômica e morfológica do complexo Potamotrygon orbignyi (Castelnau, 1855) (Chondrichthyes: Myliobatiformes: Potamotrygonidae). Unpubl. Master’s diss., Universidade de São Paulo, São Paulo, xvi + 198p.
Silva, J.P.C.B. da & Carvalho, M.R. de (2011) A taxonomic and morphological redescription of Potamotrygon falkneri Castex & Maciel, 1963 (Chondrichthyes: Myliobatiformes: Potamotrygonidae). Neotropical Ichthyology, 9 (1), 209–232.
Stehmann, M.F.W., McEachran, J.D. & Vergara, R. (1978) Batoids. [pag. var.] In: Fischer, W. (Ed.), FAO species identification sheets for fishery purposes. Western Central Atlantic (Fishing Area 31). Vol. 1. [pag. var.]. Food and Agriculture Organization of the United Nations (FAO), Rome.
Taphorn, D., Royero, R., Machado-Allison, A. & Mago Leccia, F. (1997) Lista actualizada de los peces de agua dulce de Venezuela. Pp. 55–100. In: La Marca, E. (Ed.), Catálogo zoológico de Venezuela. Vol. 1. Vertebrados actuales y fosiles de Venezuela. Museo de Ciencia y Tecnologia de Mérida, Mérida, 275p.
Toffoli, D., Hrbek, T., Araújo, M.L.G. de, Almeida, M.P. de, Charvet-Almeida, P. & Farias, I.P. (2008) A test of the utility of DNA barcoding in the radiation of the freshwater stingray genus Potamotrygon (Potamotrygonidae, Myliobatiformes). Genetics and Molecular Biology, 31 (1) (suppl), 324–336.
Thorson, T.B., Brooks, D.R. & Mayes, M.A. (1983) The evolution of freshwater adaptation in stingrays. National Geographic Society Research Reports, 15, 663–694.
Winemiller, K.O., López-Fernández, H., Taphorn, D.C., Nico, L.G. & Duque, A.B. (2008) Fish assemblages of the Casiquiare River, a corridor and zoogeographical filter for dispersal between the Orinoco and Amazon basins. Journal of Biogeography, 35 (9), 1551–1563.