New species of Trachycorystes Bleeker, with comments on other species of the genus (Ostariophysi: Siluriformes: Auchenipteridae)

Abstract

A new species of Trachycorystes from the rio Aripuanã, above Dardanelos and Andorinhas falls, is described. The new species is distinguished from the only other species of the genus, T. trachycorystes, by the following characteristics: jaws of equal length (vs. lower jaw prognathous in T. trachycorystes); skull roof covered by thick (vs. thin) integument; inner mental barbel very thin and short not reaching base of outer barbel (vs. extending to or beyond base of outer mental barbel); dorsal-fin spine serrated posteriorly, smooth or rough anteriorly (vs. serrated anteriorly and smooth or rough posteriorly); caudal fin shallowly forked (vs. emarginate); and gas bladder simple, without diverticula (vs. with three posterior diverticula). Comments and data on the nominal species Trachycorystes trachycorystes are provided. Trachycorystes cratensis Miranda Ribeiro, 1937, is allocated to the genus Trachelyopterus Valenciennes, 1840, and another local catfish species, Parotocinclus aripuanensis Garavello, 1988, has its type locality reassigned.Descreve-se uma espécie nova de Trachycorystes proveniente do curso superior do rio Aripuanã, acima das cachoeiras Dardanelos e Andorinhas. A espécie nova diferencia-se da outra espécie do gênero, T. trachycorystes, pelos seguintes caracteres: maxilas de mesmo comprimento, isto é, mandíbula não prognata (vs. mandíbula prognata em T. trachycorystes); teto do crânio coberto com pele espessa (vs. fina); barbilhão mental muito fino e curto não alcançando a base do barbilhão pós-mental (vs. estendendo-se até a base do barbilhão pós-mental ou além); espinho da nadadeira dorsal com a borda anterior lisa ou rugosa e a posterior com serras retrorsas (vs. borda anterior com serras e a posterior lisa ou rugosa); nadadeira caudal bifurcada (vs. emarginada); bexiga natatória simples, sem divertículos (vs. com três divertículos posteriores). Comentários e dados sobre as outras espécies nominais de Trachycorystes são apresentados. Trachycorystes cratensis Miranda Ribeiro, 1937, é transferido para o gênero Trachelyopterus Valenciennes, 1840, e retificam-se dados sobre a localidade-tipo de Parotocinclus aripuanensis Garavello, 1988.

Hyphessobrycon platyodus (Teleostei: Characiformes), a new species from the Rio Madeira basin, Brazil, with comments on how multicuspid teeth relate to feeding habits in Characidae

“…Based on personal observations and interviews with local fishermen, the fish fauna above Paredão Waterfall, is only composed of small to medium size fishes (see above), with large species absent ( ≥ 300 mm L S ). A similar community shift was observed from the upper Rio Aripuanã above the Dardanelos and Andorinha waterfalls (10° 09′ 48·7 ″ S; 59° 27′ 26 ″ W) (Britski & Akama, ), where medium to large carnivores are naturally absent (W. M. Ohara pers. obs.).…”

A new colorful species of Geophagus (Teleostei: Cichlidae), endemic to the rio Aripuanã in the Amazon basin of Brazil

“…From that list of species, Lasiancistrus scolymus Nijssen & Isbrücker (Loricariidae) is now considered a synonym of the widespread L. schomburgkii (Günther) (Armbruster, 2005); and Crenicichla guentheri Ploeg has been synonymized with the local endemic C. hemera Kullander (Varella et al, 2012). A species overlooked by Kullander (1995), Utiaritichthys longidorsalis Jégu, Tito de Morais & Santos (Serrasalmidae), and the recently described Trachycorystes menezesi Britski & Akama (Auchenipteridae) and Hypostomus dardanelos Zawadzki & Carvalho (Loricariidae) should be added to the list, changing the number of valid species considered endemic to that region to 11, including Geophagus mirabilis (Jégu et al, 1992;Britski & Akama, 2011;Zawadzki & Carvalho, 2014). If we consider all of the species thought to be endemic to the rio Aripuanã basin as a whole, the number rises to at least 15 (Rocha et al, 2008a(Rocha et al, , 2008bZanata & Ohara, 2009;Ribeiro et al, 2011;Eschmeyer, 2014).…”

A preliminary inventory of the catfishes of the lower Rio Nhamundá, Brazil (Ostariophysi, Siluriformes)

“…Identification to species level follows Britski and Akama (2011) based on the following characters: lower jaw prognathus; skull roof covered by thin integument; inner mental barbel reaching base of outer mental barbel; dorsal-fin spine serrated only along anterior margin; and caudal fin emarginate (our specimens had suffered damage to the lobes of the caudal fin, presumably due to piranhas).…”