A new species of Moenkhausia Eigenmann (Characiformes: Characidae) from the upper rio Machado at Chapada dos Parecis, rio Madeira basin, Brazil

Abstract

A new species of Moenkhausia is described from the upper rio Machado at Chapada dos Parecis, rio Madeira basin, Rondônia State, Brazil. Among congeners, the new species is similar to Moenkhausia chlorophthalma, M. cotinho, M. lineomaculata, M. plumbea, and M. petymbuaba by having dark blotches on the anterior portion of the body scales, which are absent in the remaining species of the genus. The new species differs from aforementioned species by possessing blue eyes in life, 15-18 branched anal-fin rays, and a well-defined, round caudal-peduncle spot that does not reach the upper and lower margins of the caudal peduncle and does not extend to the tip of the middle caudal-fin rays.Uma espécie nova de Moenkhausia é descrita do alto rio Machado na Chapada dos Parecis, bacia do rio Madeira, Rondônia, Brasil. Entre as congêneres, a espécie nova é semelhante à Moenkhausia chlorophthalma, M. cotinho, M. lineomaculata, M. plumbea e M. petymbuaba por ter manchas escuras na região anterior das escamas, que estão ausentes nas demais espécies do gênero. A espécie nova difere das espécies mencionadas acima por possuir olhos azuis em vida, 15-18 raios ramificados na nadadeira anal e uma mancha arredondada bem definida no pedúnculo caudal, que não alcança o limite superior e inferior do pedúnculo caudal, e não se estende sobre os raios medianos da nadadeira caudal.

Two new, remarkably colored species of the Neotropical catfish genus Cetopsorhamdia Eigenmann & Fisher, 1916 (Siluriformes, Heptapteridae) from Chapada dos Parecis, western Brazil, with an assessment of the morphological characters bearing on their phylogenetic relationships

“…11). Similar habitat and environmental conditions have been reported by Ohara & Lima (2015) and Ohara & Marinho (2016) Ohara, Tencatt & Britto, 2016) and Pyrrhulina sp. That tributary was categorized as a "terra-firme igarapé" (= highland creek), with its sampled stretch located at 585 m above sea level, described as being small, 1.5-2.5 m wide and 0.3-1.5 m deep, with clear and swift waters, and bottom composed of sand and dead leaves, with little preserved riparian vegetation and surrounded by large plantation fields (mostly soy and corn) (Ohara & Lima, 2015: fig.…”

“…Further on the two new Cetopsorhamdia species herein described, the following taxa are endemic to the headwaters of the rivers draining the Chapada dos Parecis: Bryconops piracolina, Hasemania nambiquara Bertaco & Malabarba, 2007, Hemigrammus silimoni Britski & Lima, 2008, Hemigrammus skolioplatus Bertaco & Carvalho, 2005b, Hyphessobrycon hexastichos Bertaco & Carvalho, 2005a, Hyphessobrycon lucenorum, Hyphessobrycon petricolus Ohara, Lima & Barros, 2017, Hyphessobrycon melanostichos Carvalho & Bertaco, 2006, Hyphessobrycon notidanos Carvalho & Bertaco, 2006, Moenkhausia cosmops Lima, Britski & Machado, 2007, Corydoras hephaestus (Callichthyidae), Ancistrus verecundus, and the monotypic genus Araichthys Zawadzki, Bifi & Mariotto, 2016, with A. loro Zawadzki, Bifi & Mariotto, 2016(Loricariidae) (cf. Bertaco & Carvalho, 2005aFisch-Muller et al, 2005;Carvalho & Bertaco, 2006;Bertaco & Malabarba, 2007;Lima et al, 2007;Britski & Lima, 2008;Wingert & Malabarba, 2011;Ohara & Lima, 2015;Ohara & Marinho, 2016;Ohara et al, , 2017Zawadzki et al, 2016).…”

“…As is the case for the whole family Heptapteridae (Bockmann, 1998;Bockmann & Guazzelli, 2003), the alpha diversity of Cetopsorhamdia is considerably underestimated, containing at least eight species pending description, some of which have already been listed in catalogs and faunistic works (cf. Ohara & Lima, 2015;Ohara & Loeb, 2016;Ohara & Marinho, 2016;. During the Brazilian leg of the Transcontinental Catfish Expedition, funded by the All Catfish Species Inventory Project, carried out mainly across the upper Paraguay, upper Tapajós, upper and middle Madeira and Purus, at least 38 new catfishes have been unveiled (Reis, 2005).…”

Ichthyofauna of the upper Juruena river on Chapada dos Parecis, Mato Grosso, Brazil

“…Although, Hyphessobrycon hexastichos and H. melanostichos have distribution range apparently restricted to the Chapada dos Parecis, they also were collected in the upper rio Guaporé (13º14'43"S 59º54'26"W), rio Madeira basin and in the igarapé Piracolina (12º49'58"S 60º06'34"W), upper rio Machado, rio Madeira basin (cf. Ohara & Lima 2015, Ohara & Marinho 2016, Ohara et al 2016, respectively. So Hyphessobrycon hexastichos and H. melanostichos are not herein considered as endemic species for the upper rio Tapajós.…”

Fishes from the Jaru Biological Reserve, Machado River drainage, Madeira River basin, Rondônia State, northern Brazil

“…The current work contributed 24 species to the general inventory of the Machado River and 26 species to the inventory conducted in Conservation Units in the Rondônia State. Additionally, the material deposited in the Brazilian collections enabled the accomplishment of recent taxonomic studies, which contributed to enhancing the knowledge of the ichthyofauna of both the Madeira River (Rocha et al 2008a, Rocha et al 2008b, Zanata & Ohara 2009, Ribeiro et al 2011, Ohara 2012, Marinho & Ohara 2013, Zanata & Ohara 2015, Ohara & Lima 2015a, Tencatt & Ohara 2016a, Ohara & Neuhaus 2016, Pastana & Ohara 2016, and the Machado River (Ohara & Lima 2015b, Ohara & Marinho 2016.…”