Trichomycterus maracaya, a new catfish from the upper rio Paraná, southeastern Brazil (Siluriformes: Trichomycteridae), with notes on the T. brasiliensis species-complex

Abstract

Trichomycterus maracaya, a new species of Trichomycteridae, is described from a streamlet in the upper rio Paraná, Poços de Caldas, State of Minas Gerais, southeastern Brazil. The following putative autapomorphies distinguishes T. maracaya from congeneric species: 1) row of lateral blotches not forming a stripe at any phase during ontogeny; 2) superficial layer of pigmentation of juveniles and large (presumably adults) specimens consisting solely of scattered chromatophores. Furthermore, the new species is characterized by a combination of yellow ground color in life and mottled pattern formed by small to medium-sized, brown, irregularly-coalescent, well-defined deeper-lying blotches, and more superficial dots on the body. Trichomycterus maracaya is assigned to the T. brasiliensis species-complex (which includes T. brasiliensis, T. iheringi, T. mimonha, T. potschi, T. vermiculatus, and several undescribed species apparently endemic to the main river basins draining the Brazilian Shield) based on the presence of: 1) blotches in four longitudinal rows of deeper-lying pigmentation on the trunk large, horizontally-elongated, and well-defined; 2) pectoral fin with I+5-6 rays; 3) separation between the anterior and posterior cranial fontanels by the primordial epiphyseal cartilaginous bar being present only in larger specimens; and 4) pelvic-fin bases very close to each other, sometimes in contact.Trichomycterus maracaya, uma espécie nova de Trichomycteridae, é descrita de exemplares obtidos num riacho do alto rio Paraná, Poços de Caldas, Estado de Minas Gerais, sudeste do Brasil. As seguintes supostas autapomorfias distinguem T. maracaya de outras espécies do gênero: 1) fileira de manchas laterais que não se fundem em listra em nenhuma fase da ontogenia; 2) camada superficial de pigmentação de juvenis e exemplares maiores (supostamente adultos) consistindo somente de cromatóforos dispersos. Além disso, a nova espécie é caracterizada pela combinação de coloração de fundo amarela em vida e padrão mosqueado, formado por manchas castanhas pequenas a médias bem definidas e aglutinadas irregularmente, situadas em camada mais profunda do tegumento, além de pontos mais superficiais espalhados pelo corpo. Trichomycterus maracaya é aqui designada ao complexo de espécies T. brasiliensis (que inclui T. brasiliensis, T. iheringi, T. mimonha, T. potschi e T. vermiculatus, além de várias espécies não descritas, aparentemente endêmicas às bacias dos rios principais que drenam o Escudo Brasileiro), com base em: 1) manchas horizontalmente alongadas, grandes e bem definidas, situadas mais profundamente no tegumento e dispostas em quatro fileiras longitudinais no corpo; 2) nadadeira peitoral com I+5-6 raios; 3) separação entre as fontanelas cranianas anterior e posterior, por barra cartilaginosa primordial da epífise, apenas nos exemplares maiores; e 4) bases das nadadeiras pélvicas muito próximas uma da outra, por vezes em contato.

A new species of Trichomycterus (Siluriformes: Trichomycteridae) from lagoa Feia drainage, southeastern Brazil

“…The color pattern in Trichomycterus caipora, composed by blotches on trunk arranged in four longitudinal rows is present in many other Trichomycterinae species (Bockmann & Sazima, 2004). In T. caipora the blotches sometimes coalesce forming well-defined [e. g., T. giganteus, T. maracaya, T. pauciradiatus, and T. variegatus] or interrupted stripe [e. g., T. albinotatus, T. alternatus, T. caudofasciatus, T. maracaya, and T. variegatus].…”

“…Although the relationships among large clades within the family Trichomycteridae are relatively well understood (de Pinna, 1998), the relationships among the Trichomycterinae, at the species-level are scarce and not based on strictly phylogenetic criteria (Costa, 1992;de Pinna, 1992;Barbosa & Costa, 2003;Bockmann & Sazima, 2004;Wosiacki & de Pinna, 2008a,b). Besides the enormous specific diversity of Trichomycterus, the non-monophyletic nature of the Trichomycterinae (de Pinna, 1989) makes it difficult to establish well defined outgroups and, consequently, consistent polarities and unequivocal intrageneric synapomorphies (de Pinna, 1992;Bockmann & Sazima, 2004 by Trichomycterus caipora and other Trichomycterus species, as well as their putative relationships can be discussed.…”

“…Besides the enormous specific diversity of Trichomycterus, the non-monophyletic nature of the Trichomycterinae (de Pinna, 1989) makes it difficult to establish well defined outgroups and, consequently, consistent polarities and unequivocal intrageneric synapomorphies (de Pinna, 1992;Bockmann & Sazima, 2004 by Trichomycterus caipora and other Trichomycterus species, as well as their putative relationships can be discussed. Trichomycterus caipora could be closely related to the type species of the genus, T. nigricans , and to T. immaculatus and T. giganteus based on the presence of nine pectoral-fin rays (i+8) and more odontodes (interopercular 59-70, vs. 19-52, opercular 23-30, vs. 10-20).…”

“…Despite the large number of species and taxonomic problems, many species of Trichomycterus have been described recently (e.g., Fernández & Schaefer, 2005;Sarmento-Soares et al, 2005;Wosiacki, 2005;Wosiacki & Oyakawa, 2005;Alencar & Costa, 2006;Fernández & Osinaga, 2006;Castellanos-Morales, 2007;Fernández & Chuquihuamaní, 2007;Fernández & Miranda, 2007;Castellanos-Morales, 2008;Wosiacki & de Pinna, 2008a,b) and many more are waiting to be described, since the majority of species have limited distribution, displaying a high level of endemism (Eigenmann, 1918;Costa, 1992;Bockmann & Sazima, 2004). Since just a few species are known to occur outside the watersheds from which they were described [e. g., Trichomycterus brasiliensis Lütken and T. zonatus (Eigenmann)] and these wide-range species may constitute species-complexes (Barbosa & Costa, 2003;Bockmann & Sazima, 2004), the typical approach for osteological and morphological comparison is to focus only on the 49 southern and southeastern Brazilian species of Trichomycterus [T.albinotatus Costa, T. alternatus (Eigenmann) Costa, T. vermiculatus (Eigenmann), T. zonatus (Eigenmann)] all from rio Paraná, rio São Francisco and coastal Atlantic basins, disregarding northern and Andean species .…”

“…Since just a few species are known to occur outside the watersheds from which they were described [e. g., Trichomycterus brasiliensis Lütken and T. zonatus (Eigenmann)] and these wide-range species may constitute species-complexes (Barbosa & Costa, 2003;Bockmann & Sazima, 2004), the typical approach for osteological and morphological comparison is to focus only on the 49 southern and southeastern Brazilian species of Trichomycterus [T.albinotatus Costa, T. alternatus (Eigenmann) Costa, T. vermiculatus (Eigenmann), T. zonatus (Eigenmann)] all from rio Paraná, rio São Francisco and coastal Atlantic basins, disregarding northern and Andean species .…”