Two new species of miniature psammophilic sarcoglanidine catfishes of the genus Microcambeva from the Atlantic Forest of eastern Brazil (Siluriformes: Trichomycteridae)

ABSTRACT

Trichomycterid catfishes of the Sarcoglanidinae, which includes small-sized species living in sandy river substratum, have been poorly represented in collections. We herein describe two new species of the sarcoglanidine genus Microcambeva, endemic to river basins draining the Brazilian Atlantic Forest. The presence of a distal widening on the posterior process of the autopalatine and a rudimentary anterior autopalatine ossification shared by the two new species, M. mucuriensis sp. nov. from the Rio Mucuri and M. jucuensis sp. nov. from the Rio Jucu basin, and M. draco from the Rio Jucuruçu basin indicates that these three species are more closely related to each other than to other congeners. Microcambeva mucuriensis seems to be more closely related to M. draco than to M. jucuensis in that the first two species share the presence of a well-developed anterior process of the interopercle. The two new species are also distinguished from congeners by the number of opercular odontodes and premaxillary teeth, and the relative size of the sesamoid supraorbital. Available evidence taken from this study and previous reports indicates that different sarcoglanidine lineages have adapted to live in distinct riverine habitats, with species of Atlantic Forest Microcambeva inhabiting clearwater streams and Amazonian sarcoglanidines found in tea-stained acidic-water streams.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:8CFF9C88-1CEC-44AF-AD26-1D4A56F3D946

KEYWORDS:

• biodiversity hotspot
• clearwater rivers
• Rio Jucu
• Rio Mucuri
• sand-dwelling fish
• systematics

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

WJEMC was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq [307349/2015-2]; AMK was supported by CNPq [153329/2015-7]; JLOM was supported by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ [E-26/202.327-328/2018]; FSRP was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES [1456769]. This study was also supported by CAPES [Finance Code 001] through Programa de Pós-Graduação em Biodiversidade e Biologia Evolutiva/UFRJ and Programa de Pós-Graduação em Zoologia, Museu Nacional/UFRJ.