A new species of Bryconops (Teleostei: Characidae) from the rio Madeira basin, Northern Brazil

Abstract

A new species of Bryconops is described from a tributary to the rio Madeira in the Amazon basin, State of Rondônia, Brazil. Bryconops piracolina belongs to the subgenus Bryconops by having no teeth or rarely one tooth in the maxilla, and a naked area on cheek between the second and third infraorbitals. The new species is distinguished from all species of this subgenus by the presence of a large black blotch on dorsal-fin base. Furthermore, it is distinguished from all congeners, except B. inpai, by possessing the adipose fin entirely black. It differs from B. inpai by the lack of humeral spots. It further differs from all species of the subgenus Bryconops, except B. caudomaculatus, by having the last scales of the longitudinal series of scales that bears the lateral line series not pored beyond the end of the hypural plate, and differs from B. caudomaculatus by the smaller number of pored lateral line scales (31-36, mean 34.6, vs. 37-43, mean = 40.6, respectively).Uma nova espécie de Bryconops é descrita para um tributário do rio Madeira na bacia do rio Amazonas, Brasil. Bryconops piracolina pertence ao subgênero Bryconops por não possuir dentes ou raramente apresentar apenas um dente na maxila, e por possuir uma área nua na face entre o segundo e terceiro infraorbitais. A espécie nova se distingue de todas as espécies do subgênero Bryconops pela presença de uma grande mancha negra na base da nadadeira dorsal. Além disto, difere de todas as espécies do gênero, exceto B. inpai, por possuir a nadadeira adiposa inteiramente preta. Difere de B. inpai pela ausência de manchas umerais. Difere de todas as espécies de Bryconops, exceto B. caudomaculatus, por possuir as últimas escamas da série longitudinal de escamas da linha lateral sem poros além da terminação da placa hipural e difere de B. caudomaculatus pelo menor número de escamas com poros da linha lateral (31-36, média 34,6 vs. 37-43 média, 40,6; respectivamente).

Fish fauna of moderate altitude from first order stream in upper Rio Machado, Rondônia, Brazil

“…A similar result was obtained by Ohara & Loeb (2016), in a headwater stream of the upper Rio Juruena (Rio Tapajós basin), also situated in the Chapada dos Parecis, indicating that altitudinal streams can have different fish composition and diversity in comparison to the lowland river channels and streams in the Amazon basin. Up to the present date, the only previous records of fishes from the upper parts of Rio Machado are those resultants from new species descriptions from the area (Vari & Harold, 2001;Fisch-Müller et al, 2005;Wingert & Malabarba, 2011;Ohara & Lima, 2015;Ohara & Marinho, 2016;. Some of these species are found exclusively in headwaters of the upper Rio Machado in the Chapada dos Parecis, such as Ancistrus verecundus Fisch-Muller, Cardoso, da Silva & Bertaco, 2005, Bryconops piracolina Wingert & Malabarba, 2011, Hyphessobrycon lucenorum Ohara & Lima, 2015, Moenkhausia parecis Ohara & Marinho, 2016, and M. cambacica Marinho, Ohara & Dagosta, 2021.…”

“…Fishes were anesthetized with clove oil (Eugenol, 10 mg per liter, as indicated by the AVMA, 2013), fixed in 10% formalin, and posteriorly transferred to 70% ethanol. Fishes were then counted and identified according Queiroz et al (2013a), Ohara et al (2017) and original description of species (e.g., Wingert & Malabarba, 2011;Fisch-Müller et al, 2005;Ohara & Lima, 2015;Ohara & Marinho, 2016). Higher-rank taxonomic classification follows Fricke et al (2022).…”

“…Its headwaters are located at the southeastern border of Rondônia at Chapada dos Parecis, a watershed between three river basins (Madeira, Paraguay and Tapajós). This region is also the type locality of many recently described fish species (Fisch-Müller et al, 2005;Wingert & Malabarba, 2011;Ohara & Lima, 2015;Ohara & Marinho, 2016;Bockmann & Reis, 2021;Marinho et al, 2021). The majority of these species seem to have very restricted distribution, since they were not recorded during previous surveys in the Rio Machado basin (e.g., Perin et al, 2007;Casatti et al, 2013;Costa et al, 2017), in other rivers of the Rio Madeira basin (e.g., Rapp Py-Daniel et al, 2007;Araújo et al, 2009;Pedroza et al, 2012;Queiroz et al, 2013a, b;Vieira et al, 2016;Anjos et al, 2019;Oliveira et al, 2020), or in neighboring drainages (Ohara & Loeb, 2016;Ohara et al, 2017).…”

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

“…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).…”

A new species of Bryconops (Ostariophysi: Characiformes: Characidae) from the upper rio Tocantins drainage, Brazil

“…Bryconops Kner, a genus of the characiform family Characidae, comprises 20 valid species of small characids distributed across a major portion of South America through the Orinoco, Amazon, Tocantins-Araguaia, Paraná-Paraguay, and São Francisco river basins to many of the smaller river systems of the Atlantic versant from the Essequibo to Oyapock (Lima et al, 2003;Chernoff & Machado-Allison, 2005;Wingert & Malabarba, 2011;Silva-Oliveira et al, 2015). Bryconops is presumably a monophyletic genus diagnosed by synapomorphies related to the anatomy of cephalic sensory system and shape of the maxillary bone (Chernoff & MachadoAllison (1999).…”