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| Cambeva flavopicta Costa, Feltrin & Katz, 2020 DOI: 10.3897/zse.96.56247 |
Abstract
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.
Key Words: Mountain biodiversity, osteology, Rio Uruguai basin, Serra Geral, systematics
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| Cambeva flavopicta sp. nov., UFRJ 12665, holotype, 69.2 mm SL: A. Left lateral view; B. Dorsal view; C. Ventral view. |
Cambeva flavopicta sp. nov.
Diagnosis: Cambeva flavopicta is distinguished from all other congeners, except C. pascuali and C. tropeiro, by the absence of pelvic fin and pelvic girdle (vs. pelvic fin and girdle present and well-developed). It is distinguished from both C. pascuali and C. tropeiro by having 6 pectoral-fin rays (vs. 5 in C. pascuali and 7 in C. tropeiro), more dorsal procurrent caudal-fin rays (20–23 vs. 17–18 in C. pascuali and 14–15 in C. tropeiro), more opercular odontodes (15–20 vs. 10–12 in C. pascuali and 12–14 in C. tropeiro), more interopercular odontodes (25–30 vs. 11–12 in C. pascuali and 18–24 in C. tropeiro) and colour pattern consisting of flank dark brownish-grey with two irregular horizontal rows of small pale yellow grey marks (vs. flank pale yellow with dark brown stripes or horizontal rows of spots in C. pascuali and flank yellowish-brown with dark brown spots irregularly arranged in C. tropeiro). Cambeva flavopicta also differs from C. pascuali by the presence of the anterior section of the infra-orbital canal (vs. absence), more vertebrae (38–39 vs. 37) and more branchiostegal rays (9 vs. 7); and from C. tropeiro by having more ventral procurrent caudal-fin rays (16–17 vs. 10–11), the first pectoral-fin ray terminating in a short filament (vs. without a filament) and caudal fin rounded (vs. subtruncate).
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| Rio Inferno Grande (upper Rio Uruguai basin, Santa Catarina, Brazil), at the exact point where the holotype and paratypes of Cambeva flavopicta sp. nov. were collected. |
Distribution and habitat: Cambeva flavopicta is only known from the upper Rio Inferno Grande and tributaries, Rio Canoas drainage, upper Rio Uruguai basin, southern Brazil (Fig. 3). The collecting sites were typical mountain rivers draining the Serra Geral, with fast flowing waters (Fig. 4). The species was found close to the riverbank, buried below marginal vegetation.
Etymology: From the Latin, the name flavopicta (painted with yellow) refers to the characteristic colouration of this new species, with yellow marks over dark brown ground.
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| Map of geographical distribution of Cambeva flavopicta sp. nov. (triangle), and type localities of C. diatropoporos (diamond), C. pascuali (pentagon), C. poikilos (star) and C. tropeiro (dot). |
Wilson J. E. M. Costa, Caio R. M. Feltrin and Axel M. Katz. 2020. A New Species from subtropical Brazil and Evidence of Multiple Pelvic Fin Losses in Catfishes of the Genus Cambeva (Siluriformes, Trichomycteridae). Zoosystematics and Evolution. 96(2): 715-722. DOI: 10.3897/zse.96.56247
