Filling distribution gaps: Two new species of the catfish genus Cambeva from southern Brazilian Atlantic Forest (Siluriformes, Trichomycteridae)

Abstract

The fauna and flora of the Brazilian Atlantic Forest have been intensively inventoried since the 19th century, but some components of this rich biota are still poorly known, and some areas have been poorly sampled. Recent studies on a rich collection of mountain catfishes of the genus Cambeva have revealed a high diversity of species still undescribed in the region. Here we provide formal descriptions for two of these species, found in areas inserted in a broad gap of the presently known genus distribution. The first one is endemic to small coastal river basins of Santa Catarina state, southern Brazil; it is tentatively placed in an intrageneric clade, also including C. castroi, C. davisi, C. guareiensis and C. zonata, by all sharing the presence of a flat small process on the dorsal margin of the quadrate, laterally overlapping metapterygoid and situated just posterior to the syncondrial joint between the metapterygoid and the quadrate. Phylogenetic relationships of the second new species, endemic to the Rio Itajaí-Mirim basin, are still obscure, but it shares a derived morphology of the mesethmoid with some species of the C. balios group. Although species of Cambeva have little external morphological variation when compared to other trichomycterine groups, the present study once more shows the importance of recording and using osteological characters to diagnose externally similar trichomycterine species.

A new catfish species of the genus Cambeva (Siluriformes: Trichomycteridae) from the Rio Iguaçu drainage, southern Brazil, with a remarkable unique colour pattern

“…On the contrary, different projections on the lateral ethmoid have been documented among congeners, as well as the shape of the parurohyal is highly variable among species of the CST clade, making the uniqueness of those two character states shared by C. castroi and C. melanoptera a still weak evidence of close relationships.The presence of a small process on the dorsal margin of the quadrate just posterior to the cartilage block articulating quadrate and metapterygoid in C. castroi (Figure3d) deserves mention. A similar condition was first described by for C. diabola and later reported to occur in other congeners(Costa et al, 2021a;dos Reis et al, 2021). This process was not present in C. melanoptera, as well as in the three specimens of C. diabola here examined, indicating that this condition may have a variableF I G U R E 5 Habitat at the type locality of Cambeva melanoptera occurrence in species of Cambeva from southern Brazil and therefore being ambiguous for inferring relationships.…”

“…Comparative material is found in Costa (2021), with the addition of Cambeva balios (Ferrer & Malabarba, 2013) (Ferrer & Malabarba, 2013) (UFRJ 6935, 2 C&S), besides specimens of congeners described more recently (Costa et al, 2021a(Costa et al, , 2021b(Costa et al, , 2022. Geographical names correspond to Portuguese names used in the region.…”

“…The protocol described by Taylor and van Dyke (1985) was used to clear and stain specimens (C&S in lists of specimens) for osteological examination. Osteological structures are those presenting informative variability among congeners (Costa et al ., 2020b, 2021a, 2021b), including the upper jaw and adjacent structures, jaw suspensorium, opercular series and parurohyal. Osteological terminology follows Costa (2021).…”

“…120 species. Nonetheless, the number of species included in Cambeva is quickly increasing since the genus description, presently reaching 40 valid species and others waiting formal description (Costa et al ., 2021a, 2021b; dos Reis et al ., 2021).…”

A new species of Cambeva (Siluriformes, Trichomycteridae) from the Rio Iguaçu basin, Paraná State, Brazil and redescription of Cambeva stawiarski (Miranda Ribeiro 1968)

“…institutional abbreviations follow Sabaj (2019). The data obtained were compared directly with specimens (see comparative material) and the following papers: Wosiacki and de Pinna (2008aPinna ( , 2008b, Miranda , Terán et al (2017), Malabarba (2011, 2013), Costa et al (2020Costa et al ( , 2021, de Pinna (1992b), Costa (1992), Bockmann et al (2004), Wosiacki (2005), Katz and Costa (2020), Reis et al (2020b), Wosiacki and Garavello (2004), Eigenmann (1917), Ochoa et al (2017b), Datovo et al (2012), Wosiacki and Oyakawa (2005), Katz and Barbosa (2014), Nascimento et al (2017), Silva et al (2010), Reis and de Pinna (2019), Donin et al (2020).…”