Taxonomic assessment of the Hard-Nosed Thornycats (Siluriformes: Doradidae: Trachydoras Eigenmann 1925) with description of Trachydoras gepharti, n. sp.

摘要: ABSTRACT. Trachydoras is a genus of Doradidae (thorny catfishes) with five nominal valid species distributed in lowland areas the Amazon, Orinoco, Parana-Paraguay and Essequibo river basins South America. A sixth described here as gepharti diagnosed by characteristics unique among congeners: mental barbels thick, tapered profusely ornamented many elongate fleshy papillae loosely arranged 2–3 rows (vs. thinner, lacking or fewer, 1–2 rows); distinct columns small, soft along medial lateral margins gill filaments on all arches conspicuous congeners); gas bladder acorn-shaped cordiform) smooth anterolateral shoulder accessory diverticulum) terminal diverticula medially united into singular, finger-like projection formed mostly elongation only one two posterior chambers both elongated, contributing more ...