A new species of the loricariid genus Lithogenes Eigenmann, 1909, is described on the basis of 84 specimens captured from a single locality in the upper Río Orinoco drainage of southern Venezuela. The new species is only the third representative of the subfamily Lithogeninae to be recognized in the 100 years since the discovery of the type species, L. villosus, and is the only lithogenine known from more than a handful of specimens. This new material provides the basis for a comprehensive review of lithogenine systematics, comparative anatomy, and interrelationships. Lithogenes wahari, new species, shares with its congeners the dermal plates of the trunk comprised of three paired series, presence of a bifurcate levator arcus palatini crest and expanded lateral lamina of the hyomandibula, and the palatine sesamoid not reaching the nasal capsule, thus confirming its placement in Lithogenes among the Loricariidae. The new species is diagnosed among congeners by the absence of odontodes on the proximal portion of the ventral surface of the first pelvic-fin ray (vs. ventral pad covered with embedded odontodes along entire length) and thickened skin of the pelvic pad forming extensive ridges; accessory premaxillary teeth absent; anal fin with intense pigment band along base and diffuse spot at midlength of fin rays (vs. pigment band at base absent, fin rays dusky, without distinct spot). Characters useful for distinguishing lithogenine species are reviewed; revised diagnoses and descriptions are provided for the two previously described species in light of new character evidence. A detailed comparative analysis of the osteology and myology of L. wahari is presented and discussed relative to homologous conditions observed more broadly among the loricarioid catfishes. Of particular importance are aspects of musculoskeletal anatomy that are hitherto unknown for lithogenines, and aspects of sexual dimorphism and the anatomy of the reproductive and digestive systems that are unique or unusual among loricariid catfishes. A phylogenetic analysis of relationships among species based on morphological characters places the two Guyana Shield species (L. villosus and L.wahari) as
A new species of suckermouth armored catfish, Cordylancistrus nephelion, is described from seven specimens collected in tributaries of the Tuy River in the Caribbean Sea basin of north-central Venezuela. Cordylancistrus nephelion can be distinguished from the other species assigned to its genus by its unique color pattern, the head and body being marked with irregular white spots. Cordylancistrus nephelion is the third species of the genus described from Venezuela: Cordylancistrus torbesensis (Schultz 1944) from the Mérida mountain range (Cordillera de Mérida), Orinoco River basin; C. perijae Pérez and Provenzano 1996 from Perijá mountain range (Sierra de Perijá), Maracaibo Lake basin; and now C. nephelion from the La Costa mountain range (Cordillera de La Costa). These three species inhabit isolated foothill rivers and have very restricted geographic distributions. The extreme alteration of the Tuy River basin by humans may threaten Cordylancistrus nephelion and the other fish species endemic to the basin with extinction. An artificial key for the species assigned to the genus Cordylancistrus is presented.
A new species of catfish is described from Colombia, and provisionally assigned to the genus Cordylancistrus. The new species is most similar to C. perijae and C. nephelion from Venezuela. The description is based on ten specimens collected from tributaries of the Magdalena River which drain the eastern slope of the Cordillera Central and the western slope of Cordillera Oriental, in the Department of Tolima. The new species is the first Cordylancistrus described from the Magdalena River basin. With this discovery, the number of Cordylancistrus species in Colombia increases to three. The geographic distribution of the species suggest that Andean orogenesis played an important role in the diversification of the group.
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