Abstract
A new species of Neoplecostomus is described from the rio Doce basin representing the first species of this genus in the basin. The new species is distinguished from its congeners by having enlarged, fleshy folds between dentaries, two or three series of developed papillae anterior to premaxillary teeth and a adipose-fin membrane present, and by lacking enlarged odontodes along snout lateral margins in mature males, a well-developed dorsal-fin spinelet wider than dorsal-fin spine base, lower number of lateral-line figs and developed membrane on the dorsal portion of the first, second and third pelvic-fin branched rays. Additionally, we present a brief discussion of biogeographic scenarios that may explain the distribution of the new species in the rio Doce basin. We suggested that the ancestral lineage of the new species reached the rio Doce from the upper portions of rio Paraná drainages about 3.5 Mya (95% HPD: 1.6–5.5) indicating a colonization route of the N. doceensis ancestral lineage from the south end of Serra do Espinhaço, probably as a result of headwater capture processes between the upper rio Paraná and rio Doce basins.
Highlights
IntroductionNeoplecostominae currently includes six genera: Neoplecostomus, Isbrueckerichthys, Kronichthys, Pareiorhaphis, Pareiorhina and Pseudotocinclus (Armbruster 2004; Chiachio et al 2008; Roxo et al 2012a, b) and more than 50 valid species (Eschmeyer and Fong 2014) distributed throughout the southeastern drainage regions in South America, from Rio Grande do Sul to Bahia states, except for Pareiorhaphis regani, which occurs in the rio Negro, in the Amazon basin.Since Langeani (1990), the genus Neoplecostomus has been diagnosed as having a conspicuous series of enlarged papillae just posterior to the dentary teeth, which are larger than those on the remaining portions of the lower lip, the abdomen covered with platelets forming either a pentagonal or hexagonal shield, and the canal bearing plate on the cheek and the dorsal locking mechanism absent
Neoplecostomus doceensis has a conspicuous series of enlarged papillae just posterior to the dentary teeth, which are larger than those on the remaining portions of the lower lip
The canal bearing plate and the dorsal locking mechanism are absent, suggesting that this is a typical species of the genus Neoplecostomus, sensu Langeani (1990)
Summary
Neoplecostominae currently includes six genera: Neoplecostomus, Isbrueckerichthys, Kronichthys, Pareiorhaphis, Pareiorhina and Pseudotocinclus (Armbruster 2004; Chiachio et al 2008; Roxo et al 2012a, b) and more than 50 valid species (Eschmeyer and Fong 2014) distributed throughout the southeastern drainage regions in South America, from Rio Grande do Sul to Bahia states, except for Pareiorhaphis regani, which occurs in the rio Negro, in the Amazon basin.Since Langeani (1990), the genus Neoplecostomus has been diagnosed as having a conspicuous series of enlarged papillae just posterior to the dentary teeth, which are larger than those on the remaining portions of the lower lip, the abdomen covered with platelets forming either a pentagonal or hexagonal shield, and the canal bearing plate on the cheek and the dorsal locking mechanism absent. The genus includes 13 species (Eschmeyer 2014): N. paranensis Langeani, 1990, N. corumba Zawadzki, Pavanelli & Langeani, 2008, N. selenae Zawadzki, Pavanelli & Langeani, 2008, N. yapo Zawadzki, Pavanelli & Langeani, 2008, N. botucatu Roxo, Oliveira & Zawadzki, 2012, N. bandeirante Roxo, Oliveira & Zawadzki, 2012, N. langeanii Roxo, Oliveira & Zawadzki, 2012, all from the upper rio Paraná basin; N. franciscoensis, Langeani, (1990) from the rio São Francisco basin; N. microps (Steindachner, 1877), N. variipictus Bizerril, 1995, and N. granosus (Cuvier & Valenciennes, 1840) from the rio Paraíba do Sul basin; N. espiritosantensis Langeani, 1990 from rio Jacu basin and N. ribeirensis Langeani (1990) from rio Ribeira de Iguape basin. We present a brief discussion of biogeographic scenarios that may explain the distribution of the new species in the rio Doce basin
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