A new species of the Hypostomus cochliodongroup (Siluriformes: Loricariidae) from the rio Aripuanã basin in Brazil

Abstract

A new species of Hypostomus, H. dardanelos, is described from the rio Aripuanã basin, a southern tributary to the rio Madeira, in northern Mato Grosso State, Brazil. The new species is assigned to the Hypostomus cochliodon group by the possession of few teeth, spoon-shaped teeth, angle between dentaries usually less than 80°, and by the absence of a notch between hyomandibular and the metapterygoid. The new species can be diagnosed from its congeners by its unique color pattern of yellowish-brown ground color covered by well-defined dark spots of relatively equal size, evenly spaced and moderately set along the dorsal region of the body and fins, except on the ventrolateral region of the caudal peduncle and proximal region of anal and caudal fins, which are devoid of spots. The new species is further diagnosed by having teeth with very small lateral cusp, fused to the mesial one and almost imperceptible; by the absence of medial buccal papillae, and by nuptial odontodes all along the body (odontodes more pronounced in some few larger specimens).Uma espécie nova de Hypostomus, H. dardanelos, é descrita da bacia do rio Aripuanã, um tributário ao sul do rio Madeira, no norte do estado do Mato Grosso, Brasil. A espécie nova é atribuída ao grupo Hypostomus cochliodon por apresentar poucos dentes, dentes em forma de colher, ângulo entre os dentários usualmente menor que 80° e pela ausência de uma chanfradura entre o hiomandibular e o metapterigoide. A espécie nova pode ser diagnosticada de suas congêneres por seu padrão de cor único marrom-amarelado com pintas escuras bem definidas de tamanho homogêneo, moderadamente distanciadas e igualmente distribuídas ao longo da região dorsal do corpo e nadadeiras, exceto na região ventrolateral do pedúnculo caudal e na região proximal da nadadeira caudal, que são desprovidas de pintas. A espécie nova é adicionalmente diagnosticada por possuir dentes com a cúspide lateral muito reduzida, fundida à cúspide mesial e quase imperceptível; pela ausência da papila bucal medial e por odontódeos nupciais presentes em todo o corpo (odontódeos mais evidentes em alguns poucos exemplares maiores).

Redescription of the endangered hypoptopomatine catfish Parotocinclus spilurus (Fowler, 1941) (Siluriformes: Loricariidae) from the upper rio Jaguaribe basin, northeastern Brazil

“…3). Ontogenetic color variation is already known in some Siluriformes (Ferrer & Malabarba, 2013) and Loricariidae species (Zawadzki & Carvalho, 2014). Besides the color pattern, a few morphological variation could also be observed across the size range in P. spilurus specimens.…”

Stream Fish in the Aripuanã River Upstream and Downstream of the Dardanelos-Andorinhas Waterfall Complex, State of Mato Grosso, Brazil

“…Most of the recent articles on fish from the Aripuanã River Basin deal principally with the description of new species (e.g., Zanata & Ohara 2009, Deprá et al 2014, Zawadzki & Carvalho 2014, Pastana & Ohara 2016. Fewer articles addressing the regional composition of fish community in the region were published, namely Soares (1979), Rapp Py-Daniel et al (2007, Pedroza et al ( 2012), Fernandes et al (2013) and Flausino-Júnior et al (2016).…”

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).…”