A new species of Rineloricaria (Siluriformes: Loricariidae) from coastal drainages of Rio de Janeiro, southeastern Brazil

Abstract A new species of Rineloricaria is described from the Iguaçu, Magé, Saracuruna, Guapiaçu, Macacu, Macaé, and Paraíba do Sul River basins in southeastern Brazil based on morphological and molecular data. The new species is diagnosed among congeners by the combination of the following characters: absence of plates in most of the ventral surface of pectoral girdle; snout tip with elliptical naked area reaching posteriorly the anteriormost pore of the infraorbital ramus of sensory canal; dorsal-fin spinelet present; supraoccipital and predorsal plates with smooth keels; five series of lateral plates below the dorsal fin; median and mid-ventral series of plates with well-developed keels. The new species is distinguished from congeners that inhabit the rivers draining the Serra do Mar in Rio de Janeiro state by the partial plate coverage of the ventral surface of the pectoral girdle and the abdomen (vs. pectoral girdle and abdomen completely covered by plates in Rineloricaria nigricauda, R. steindachneri, and R. zawadzkii). The new species shares the absence of plates on the abdominal surface with other species from the Paraná, Uruguay, and other Brazilian coastal river basins.

摘要 本研究基于形态学与分子生物学数据，对巴西东南部伊瓜苏河、马热河、萨拉库鲁纳河、瓜皮亚苏河、马卡库河、马卡埃河以及南帕拉伊巴河流域的锉甲鲶属（Rineloricaria）一新种进行了记述。该新种可通过以下特征组合与同属物种区分开来：肩带腹面大部分区域无骨板；吻端具椭圆形裸露区域，其后延伸至感觉管眶下支的最前孔；具背鳍小棘；上枕骨及背前骨板具光滑棱嵴；背鳍下方具5列侧骨板；中轴及腹中轴系列骨板具发达棱嵴。该新种与栖息于里约热内卢州马尔山脉流域河流的同属物种可通过肩带与腹部腹面部分被骨板覆盖加以区分（而黑尾锉甲鲶（Rineloricaria nigricauda）、斯坦达奇锉甲鲶（R. steindachneri）以及扎瓦茨基锉甲鲶（R. zawadzkii）的肩带与腹部完全被骨板覆盖）。该新种与巴拉那河、乌拉圭河以及巴西其他沿海流域的物种一样，腹部表面无骨板覆盖。