Astyanax taurorum a new species from dos Touros River, Pelotas River drainage, an upland southern Brazilian river (Characiformes: Characidae)

Abstract

ABSTRACT. A new species of Astyanax belonging to the Astyanax scabripinnis complex is described from dos Touros River, tributary of the Pelotas River, Uruguay River basin. Astyanax taurorum sp. nov. is distinguished from other species of the Astyanax scabripinnis species complex by having two humeral spots, the first vertically elongated; teeth of inner row of premaxilla with three to five cusps; 2-3 (modes 2 or 3) maxillary teeth; 20-23 (mode 22) branched anal-fin rays; 13-15 (mode 14) gill rakers on lower branch of the first branchial arch; 20-23 (mode 21) total gill rakers in first branchial arch; 33-36 (mode 35) perforated lateral line scales. Astyanax taurorum sp. nov. is similar to Astyanax paris; nevertheless, it can be readily distinguished from it by having a smaller head depth (73.6-83.1% vs. 86.4-95.6%) and smaller interorbital width (24.1-28.0%vs. 30.8-32.8%). In addition, it differs from A. paris by the presence a posttemporal hook-shaped posterodorsal margin.

Two new species of Heptapterus (Siluriformes: Heptapteridae) from the Uruguay River basin, Brazil

“…Heptapterus carnatus is geographically restricted to the Araucaria forest plateau ecoregion in southern Brazil and to the upper portions of the Jacuí and Uruguay Rivers. Malabarba et al (2009) (Ferrer & Malabarba, 2011;Tencatt et al, 2016;Lucena et al, 2017;Reis, 2017), all endemic to this area. The description of H. carnatus adds one more species to list of fishes endemic to the Araucaria forest plateau ecoregion, highlighting the importance of aquatic conservation in this region.…”

“…() identified a high degree of fish endemism in this region, listing eight species as endemic, namely: Astyanax brachypterygium Bertaco and Malabarba 2001, Astyanax cremnobates Bertaco and Malabarba 2001, Bryconamericus patriciae da Silva 2004, Cnesterodon brevirostratus Rosa and Costa 1993, Eurycheilichthys pantherinus (Reis & Schaefer 1992), Jenynsia eirmostigma Ghedotti and Weitzman 1995, Pareiorhaphis eurycephalus Pereira and Reis 2002 and Pareiorhaphis vestigipinnis (Pereira & Reis, 1992). Additional species have since been described for the Araucaria forest plateau, such as Trichomycterus tropeiro Ferrer and Malabarba , Corydoras froehlichi Tencatt, Britto and Pavanelli , Astyanax taurorum Lucena, Zaluski & Lucena , Eurycheilichthys castaneus Reis , E. planus Reis , E. vacariensis Reis , E. coryphaenus Reis (Ferrer & Malabarba, 2011; Tencatt et al ., 2016; Lucena et al ., 2017; Reis, 2017), all endemic to this area. The description of H. carnatus adds one more species to list of fishes endemic to the Araucaria forest plateau ecoregion, highlighting the importance of aquatic conservation in this region.…”

Quadrigyrus torquatus cystacants Van Cleave, 1920 (Acanthocephala: Quadrigyridae) parasitizing species of Astyanax (Characiformes: Characidae) from southern Brazil

“…A total of 20 species of Astyanax Baird & Girard, 1854 have been reported from Rio Grande do Sul State, southern Brazil. These species are found in the Uruguay river drainage basin, Patos Lagoon system, and in Tramandaí river system (Lucena et al 2017). In Lake Guaíba the following species of Astyanax have been considered abundant: Astyanax eigenmanniorum (Cope, 1894), Astyanax aff.…”

Revalidation of Saccocoelioides bacilliformis (Digenea, Haploporidae) parasitizing species of Astyanax (Characiformes, Characidae) from southern Brazil

“…In the lake, four species of Astyanax Baird & Girard, 1854 have been reported: Astyanax eigenmanniorum (Cope, 1894), Astyanax aff. fasciatus (Cuvier, 1819), Astyanax henseli Melo &Buckup, 2006, andAstyanax lacustris (Lütken, 1875) (Lucena et al, 2013;2017). Their helminth fauna is still very poorly known and considering the trematodes, only three species of digenetic trematodes (Dendrorchis retrobiloba Volonterio & Ponce de Léon, 2005, Genarchella parva Travassos, Artigas & Pereira, 1928and Zonocotyle bicaecata Travassos, 1948 have been reported in A. aff.…”