A third pelvic-less species of Cambeva from river basins draining the Geral mountain range in southern Brazil is described. It is distinguished from other congeners lacking pelvic fin and girdle, C. pascuali and C. tropeiro, by having six pectoral-fin rays, 20–23 dorsal procurrent caudal-fin rays, 15–20 opercular and 25–30 interopercular odontodes and a different colour pattern consisting of flank dark brownish-grey with two irregular horizontal rows of small pale yellow grey marks. Whereas available molecular evidence indicates that C. pascuali is more closely related to C. zonata, a species with well-developed pelvic fin, and C. tropeiro is more closely related to C. balios, another species also with well-developed pelvic fin; osteological data strongly suggest that the new species herein described is more closely related to C. diatropoporos than to other congeners. Therefore, this study indicates that the pelvic fin and pelvic-fin support have been lost independently in each of these three species of Cambeva, which corresponds to 11% of all describe species. This result highly contrasts with the closely-related trichomycterine genera Trichomycterus, in which only one in 50 species lost pelvic fin and girdle (0.2%) and Scleronema with all the nine included species having well-developed pelvic fin. These data suggest a stronger tendency to losing pelvic fin in Cambeva, but factors favouring this evolutionary event are still unknown.

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.

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A recent field inventory focusing on catfishes of the trichomycterine genus Cambeva detected the occurrence of two morphotypes, C. barbosae and C. cubataonis, in the Guaratuba-Babitonga-Itapocu area (GBIA) of southern Brazil, reporting some discordance with results of coalescent-based approaches for species delimitation that indicated different estimates of species number. Contrastingly, based on examination of characters taken from the external morphology and osteology, we here recognised six species of Cambeva in GBIA: C. cf. botuvera, a polymorphic and geographically widespread species; C. cubataonis, endemic to the Rio Cubatão do Norte; and four new species, two endemic to the Rio Itapocu basin, one endemic to the Baía de Babitonga system and one endemic to the Baía de Guaratuba system. We performed a molecular phylogenetic analysis indicating that Cambeva comprises three major clades, the alpha-, beta- and gama-clades, with C. cf. botuvera and a clade comprising C. cubataonis and three new species belonging to the beta-clade and another new species belonging to the gama-clade. We concluded that species here recognised are not in fact incongruent with results of that recent study when taxa are correctly identified by a representative sample of morphological characters, highlighting the importance of osteological characters for delimiting trichomycterine species.