Trichomycterus tupinamba

biology_ecology

Ecological notes. The rio Betari at PETAR, the type locality of Trichomycterus tupinamba, is a clearwater river with strong to moderate current flowing over rocky beds intercalated with pools in karstic area. The river runs in an alluvial valley bordered by adjacent hills, and the riparian vegetation is composed of relatively well-preserved forest. Bellow the PETAR there are several human settlements near the rio Betari which release sewage into the river. Trichomycterus tupinamba and other siluriforms are found associated with stones and vegetable debris on the bottom. The following species of fish occur syntopically with Trichomycterus tupinamba: T. davisi, Isbrueckerichthys alipionis (Gosline), Neoplecostomus ribeirensis Langeani, Harttia kronei Miranda-Ribeiro, Rhamdioglanis frenatus Ihering, Chasmocranus lopezi Miranda-Ribeiro, Bryconamericus microcephalus (Miranda-Ribeiro), and Characidium pterostictum Gomes.

Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, Southeastern Brazil

description

Description. Morphometric data for holotype and paratypes are given in Table 1. Body elongate, roughly cylindrical close to head and gradually more compressed towards caudal fin. Dorsal and ventral profiles of trunk slightly convex. Dorsal and ventral profiles of caudal peduncle straight (Figs. 2 and 3). Integument thick, especially over base of dorsal and anal fins. Head wide and depressed, trapezoidal in dorsal view, slightly longer than wide or as long as wide (75.8 - 100.9 % HL), width at posterior tip of opercle greater than width at nostril, anterior margin of snout slightly rounded (Fig. 4). Lateral region of eye slightly swollen by jaw muscles in large and small specimens. Dorsal and ventral profiles of head straight. Eye rounded, without well-defined rim, dorsally oriented, covered by thin skin in contact with center from surface of eyeball. Ocular structures readily visible on surface of skin, not deeply sunken. Orbital rim not free. Anterior nostril surrounded by fleshy flap of integument. Posterior nostril surrounded anteriorly by thin flap of integument. Anterior and posterior nostrils approximately same diameter as eye. Gill membranes thick, attached across isthmus on

Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, Southeastern Brazil

diagnosis

Diagnosis. Trichomycterus tupinamba differs from all other species of the subfamily Trichomycterinae by the following unique combination of characters: first pectoral-fin ray not prolonged as a filament (vs. prolonged), caudal fin truncate with attenuated edges (vs. rounded), two paired supraorbital pores s 6 (vs. pores united as a single supraorbital pore s 6), eye dorsally oriented (vs. dorsolaterally oriented), mouth subterminal (vs. terminal), anal and urogenital openings mid-way between pelvic-fin margin and anal-fin origin (vs. nearer to anal-fin origin), dark spot at base of nasal barbel (vs. dark spot absent), longitudinal row of dark spots along midline of flank from opercle to caudal-fin base (vs. longitudinal lateral series of spots absent), pectoral girdle width 13.1 - 17.7 % SL, and caudal peduncle depth 8.7 - 10.3 % SL.

Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, Southeastern Brazil

distribution

Distribution. Known from the localities of the type series, rivers Betari and Iporanga, both tributaries of the rio Ribeira de Iguape.

Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, Southeastern Brazil