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

Wilson J E M Costa,Caio R M Feltrin,Axel M Katz

doi:10.3897/zse.97.61006

Abstract

The fauna and flora of the Brazilian Atlantic Forest have been intensively inventoried since the 19thcentury, 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 genusCambevahave 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 includingC. castroi,C. davisi,C. guareiensisandC. 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 theC. baliosgroup. Although species ofCambevahave 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.

Highlights

The fauna and flora of the Brazilian Atlantic Forest, considered among the most important biodiversity hotspots in the world (Myers et al 2000), have been intensively inventoried and described since the first half of the 19th century, when numerous European naturalists visited the region for the first time (e.g. Papavero 1971; Costa et al 2020a)
The objective of this paper is to provide formal descriptions for two of the new species collected in this area
Morphometric and meristic data were taken following Costa (1992), with modifications proposed by Costa et al (2020a); measurements are presented as percent of standard length (SL), except for those related to head morphology, which are expressed as percent of head length

Summary

Introduction

The fauna and flora of the Brazilian Atlantic Forest, considered among the most important biodiversity hotspots in the world (Myers et al 2000), have been intensively inventoried and described since the first half of the 19th century, when numerous European naturalists visited the region for the first time (e.g. Papavero 1971; Costa et al 2020a). Abilhoa et al 2011), studies based on expeditions conducted in the last 30 years directed to sample fish in specialised biotopes have revealed a rich still unknown species diversity, first described in recent years Costa 2009; Costa et al 2020b) Among these specialised freshwater biotopes are mountain streams, with numerous endemic fishes being first sampled and described in recent years, mainly belonging to the Trichomycterinae (Costa et al 2020c, 2020d; Donin et al 2020; dos Reis et al 2020; Vilardo et al 2020), a catfish subfamily (Siluriformes: Trichomycteridae) occurring between southern Central America and Patagonia, in southern South America (Katz et al 2018).

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