Trichomycterus payaya

biology_ecology

Habitat and ecology. Trichomycterus payaya was captured in two small streams (1 to 7 m wide and up to 1 m deep), characterized by somewhat turbid water and moderate current over sandy bottom with pebbles, relatively low altitude (505 - 547 m above sea level), and surrounding vegetation mainly composed of grasses (Fig. 9). The stomach contents of four specimens were analyzed (2 c & s, UFBA 5284, young male, 24.1 mm SL; MBML 2560, young female, 30.1 mm SL; 2 in alcohol, UFBA 5286, young female, 31.1 mm SL, and UFBA 5284, young male, 36.5 mm SL). Contents revealed the presence of Chironomidae larvae, Ephemeroptera nymphs, fragments of insects and organic matter. The new species was collected syntopically with Astyanax cf. lacustris, A. aff. fasciatus, Characidium sp., Gymnotus cf. carapo, Hoplias malabaricus, Parotocinclus bahiensis, Piabina argentea, Pimelodella itapicuruensis, Poecilia reticulata, Rhamdia quelen, Serrapinnus heterodon, S. piaba, and Steindachnerina sp.

Trichomycterus payaya, new catfish from headwaters of rio (Siluriformes: Trichomycteridae) Itapicuru, Bahia, Brazil

description

Description. Morphometric and meristic data presented in Table 1. Body slim, trunk compressed, caudal peduncle laterally compressed. Dorsal profile of body gradually ascending from tip of snout to anterior portion of trunk, approximately straight from that point to base of dorsal fin, descending along dorsalfin base and straight on caudal peduncle until caudal fin. Ventral profile of head gently sloped. Ventral profile of body almost straight to shallowly convex. Head rounded anteriorly in dorsal view, small, and slightly depressed. Eyes small, orbital margin not free; thin skin covering eye. Anterior nostril surrounded by fleshy, tubeshaped flap of integument. Posterior nostril surrounded anteriorly by raised fleshy flap and located slightly closer to anterior nostrils than to eye. Mouth subterminal; lower lip contoured by fleshy lobe medial to origin of rictal barbels; upper lip with fleshy fold limited to base of maxillary barbel. Nasal barbel originating on lateral portion of integumentary flap around anterior nostril; tip of barbel reaching opercular odontode patch. Maxillary barbel reaching pectoral-fin origin. Rictal barbel extending to interopercular odontode patch. Autopal

Trichomycterus payaya, new catfish from headwaters of rio (Siluriformes: Trichomycteridae) Itapicuru, Bahia, Brazil

diagnosis

Diagnosis. Trichomycterus payaya is distinguished from all congeners by a unique combination of features: head rounded anteriorly in dorsal view and slightly depressed in lateral view; supraorbital pores s 6 paired, opening laterally on supraorbital sensory branch, not emerging from an epiphyseal branch; lateral process of urohyal distally sharp, with pointed tip; reduced number of pleural ribs (5 - 6 ribs); and interopercular patch of odontodes longer than deep, with 21 - 26 odontodes. Trichomycterus payaya can be further distinguished from all congeners inhabiting the Brazilian coastal rivers located north of rio Paraíba do Sul (T. alternatus, T. bahianus, T. brunoi, T. caudofasciatus, T. itacambirussu, T. jequitinhonhae, T. landinga, T. longibarbatus, T. pantherinus, T. pradensis) by having the dorsal fin positioned somewhat posteriorly, the distance from the dorsal-fin origin to the base of the middle caudal-fin rays 1.9 - 2.2 in predorsal distance (vs. 1.4 - 1.8 in predorsal distance). The new species differs further from congeners of northeastern Brazilian drainages (T. bahianus, T. itacambirussu, T. jequitinhonhae, T. landinga, T. pradensis) by having a large opercular odont

Trichomycterus payaya, new catfish from headwaters of rio (Siluriformes: Trichomycteridae) Itapicuru, Bahia, Brazil

distribution

Distribution. Known from two tributaries of the rio Itapicurumirim, in the headwaters of the rio Itapicuru basin, northern Bahia State (Fig. 8).

Trichomycterus payaya, new catfish from headwaters of rio (Siluriformes: Trichomycteridae) Itapicuru, Bahia, Brazil