ABSTRACT. Trachydoras is a genus of Doradidae (thorny catfishes) with five nominal valid species distributed in lowland areas of the Amazon, Orinoco, Paraná-Paraguay and Essequibo river basins of South America. A sixth species is described here as Trachydoras gepharti and diagnosed by five characteristics unique among congeners: mental barbels thick, tapered and profusely ornamented with many elongate fleshy papillae loosely arranged in 2–3 rows (vs. mental barbels thinner, papillae lacking or fewer, arranged in 1–2 rows); distinct columns of small, soft papillae along medial and lateral margins of gill filaments on all gill arches (vs. gill filaments lacking conspicuous papillae in congeners); gas bladder acorn-shaped (vs. cordiform) with smooth anterolateral shoulder (vs. shoulder with accessory diverticulum) and terminal diverticula medially united into singular, finger-like projection formed mostly by elongation of only one of the two posterior chambers (vs. both chambers elongated, contributing more or less equally to terminal diverticula in congeners or terminal diverticula absent or reduced in some specimens of T. nattereri and T. paraguayensis). Trachydoras gepharti is known from the Amazon and Orinoco basins where it often occurs syntopically with T. microstomus, T. nattereri and a separate undescribed species of Trachydoras. Like other species of Trachydoras, T. gepharti is specialized for vacuuming chironomid larvae from sandy substrates in medium to large river channels. Redescriptions and diagnoses are provided for the five nominal valid species of Trachydoras along with a key to identification and comments on characteristics used to diagnose the genus and delimit species. Designations include a lectotype (NMW 46375, 91.7 mm SL) for Trachydoras brevis (Kner 1853) and neotype (ANSP 178443, 100 mm SL) for T. nattereri (Steindachner 1881). The true holotype of T. microstomus (Eigenmann 1912) is identified as FMNH 118302 [ex. FMNH 53207, ex. CM 1650] and the specimen previously cataloged as the holotype (FMNH 53206) is identified as T. brevis.

中文翻译：

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Hard-Nosed Thornycats (Siluriformes: Doradidae: Trachydoras Eigenmann 1925) 的分类评估以及 Trachydoras gepharti, n. 的描述。sp.

摘要。Trachydoras 是 Doradidae（多刺鲶鱼）的一个属，有五个名义上有效的物种，分布在南美洲亚马逊、奥里诺科、巴拉那-巴拉圭和埃塞奎博河流域的低地地区。第六个物种在这里被描述为 Trachydoras gepharti，并通过五个同类中独特的特征进行诊断：触须粗、锥形且装饰有许多细长的肉质乳头，松散地排列成 2-3 行（相对于细长的触须，缺乏或更少的触须，排成1-2行）；沿着所有鳃弓上的鳃丝的内侧和外侧边缘有明显的小而柔软的乳突柱（相对于在同源物中缺乏明显的乳突的鳃丝）；气囊橡子形（与心形），肩部平滑（与心形）肩部有副憩室）和末端憩室在内侧联合成单一的指状突起，主要由两个后房中的一个仅伸长形成（相对于两个后房都伸长，或多或少地对同源体中的末端憩室或无末端憩室的贡献相同）或在 T. nattereri 和 T. paraguayensis 的一些标本中减少）。Trachydoras gepharti 在亚马逊和奥里诺科盆地已知，在那里它经常与 T. microstomus、T. nattereri 和一个单独的未描述的 Trachydoras 物种同位出现。与其他 Trachydoras 物种一样，T. gepharti 专门用于从大中型河道的沙质基质中吸出摇蚊幼虫。重新描述和诊断 Trachydoras 的五个名义有效物种，以及用于诊断属和划定物种的特征的识别和评论的关键。名称包括 Trachydoras brevis (Kner 1853) 的选型 (NMW 46375, 91.7 mm SL) 和 T. nattereri (Steindachner 1881) 的新型 (ANSP 178443, 100 mm SL)。T. microstomus (Eigenmann 1912) 的真正正模被鉴定为 FMNH 118302 [ex. FMNH 53207，例如。CM 1650] 和之前编目为正模标本 (FMNH 53206) 的标本被确定为 T. brevis。microstomus (Eigenmann 1912) 被鉴定为 FMNH 118302 [ex. FMNH 53207，例如。CM 1650] 和之前编目为正模标本 (FMNH 53206) 的标本被确定为 T. brevis。microstomus (Eigenmann 1912) 被鉴定为 FMNH 118302 [ex. FMNH 53207，例如。CM 1650] 和之前编目为正模标本 (FMNH 53206) 的标本被确定为 T. brevis。