Taxonomic review of Hisonotus Eigenmann & Eigenmann (Siluriformes: Loricariidae: Hypoptopomatinae) from the laguna dos Patos system, southern Brazil

Abstract

The species of Hisonotus from the laguna dos Patos system are reviewed. Two species with wide distributions are redescribed: Hisonotus laevior and H. nigricauda. Six new species are described from that system: H. notopagos from the rio Camaquã drainage; H. carreiro and H. prata, endemic from the headwaters of rio Taquari drainage; H. vireo, widely distributed in the rio Jacuí basin; and H. brunneus and H. heterogaster restricted to tributaries of the rio Jacuí drainage. Hisonotus leptochilus is here considered a junior synonym of H. laevior. Hisonotus armatus, H. charrua, H. leucofrenatus, and H. taimensis are also present in the region and in total there are twelve species of Hisonotus in the laguna dos Patos system. Their distributions are discussed, species are illustrated and a taxonomic key is provided. As espécies de Hisonotus do sistema da laguna dos Patos são revisadas. Duas espécies com amplas distribuições são redescritas:Hisonotus laevior e H. nigricauda. Seis espécies novas são descritas deste sistema: Hisonotus notopagos, da drenagem do rio Camaquã; H. prata e H. carreiro, endêmicas das cabeceiras do rio Taquari; H. vireo, amplamente distribuída na bacia do rio Jacuí; H. brunneus e H. heterogaster dos tributários da bacia do rio Jacuí. Hisonotus leptochilus é considerado sinônimo júnior de H. laevior. Hisonotus armatus, H. charrua, H. leucofrenatus e H. taimensis também são encontradas na região, e ao total doze espécies de Hisonotus estão presentes no sistema da laguna dos Patos sendo suas distribuições discutidas aqui. As espécies são ilustradas e uma chave taxonômica é fornecida.

Taxonomic review of the genus Trichomycterus Valenciennes (Siluriformes: Trichomycteridae) from the laguna dos Patos system, Southern Brazil

“…Trichomycterus diatropoporos is endemic to the rio da Prata basin and occurs sympatrically with Hisonotus prata and an undescribed species of Eurycheilichthys, also endemic to the upper course of the rio da Prata (Carvalho & Reis, 2011). The mountain relief on which the Taquari drainage flows was considered responsible for dividing species distribution in that drainage, as exemplified by H. prata and the undescribed species of Eurycheilichthys (Carvalho & Reis, 2011), and it seems to be also correlated to the restricted distribution range of T. diatropoporos.…”

“…The mountain relief on which the Taquari drainage flows was considered responsible for dividing species distribution in that drainage, as exemplified by H. prata and the undescribed species of Eurycheilichthys (Carvalho & Reis, 2011), and it seems to be also correlated to the restricted distribution range of T. diatropoporos.…”

“…It is upstream of a waterfall known as Cascata da Usina at approximately 660 m a.s.l. At this site T. diatropoporos occurs sympatrically with Hisonotus prata Carvalho & Reis, 2011, another endemic species to the rio da Prata. The other two localities of the paratypes are located at approximately 642 m and 825 m a.s.l.…”

“…8). At the type locality the rio da Prata is a rapid flowing, wide and shallow, with an average depth of 0.5 m, with clear water, rocky bottom and large amounts of submerged vegetation (Carvalho & Reis, 2011) (Fig. 9b).…”

A new species of Astyanax Baird & Girard (Ostariophysi: Characidae) from the rio Taquari-Antas basin, southern Brazil

“…The upper rio Taquari-Antas basin is recognized as an area of endemism for hosting a large number of endemic taxa (Carvalho & Reis, 2011;Becker et al, 2013;Ferrer & Malabarba, 2013;Lucena et al, 2013aLucena et al, , 2013b. According to Becker et al (2013), species with restricted ranges are potentially more susceptible to environmental impacts and extinction, and they should be considered as targets for assessments in conservation planning and environmental licensing.…”