A new species of Hemibrycon (Characiformes: Characidae), a freshwater fish from the Sierra Nevada of Santa Marta, Caribbean drainage, Colombia

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Hemibrycon is a group of freshwater characid fish species first recognized by Gunther (1864) as a subgenus of Tetragonopterus, and now included in the subfamily Stevardiinae. There are 21 spe cies recorded from the rivers of Colombia, but only one species, H. santamartae, has been reported previously in drainages of the Sierra Nevada de Santa Marta. Hemibrycon sierraensis n. sp. is described from the Río Gaira, Caribbean coastal drainage. It is distinguished from all congeners by having in life a bright red adipose fin (vs. hyaline or trans parent) that turns dark brown in specimens preserved in alcohol. It dif fers from Hemibrycon beni, H. boquiae, H. brevispini, H. colombianus, H. mikrostiktos, H. metae, H. microformaa, H. palomae and H. rafaelense in having a vertically elongate humeral spot that extends 3-4 longitudinal scale series below the lateral line. It differs from H. divisorensis, H. pau-tensis and H. santamartae by having the last dorsal-fin ray unbranched; and from H. pautensis by the number of scale series between the lat eral line and the pelvic-fin insertions. It differs from H. divisorensis in the number of unbranched anal-fin rays, and the number of teeth on the dentary and maxilla. It differs from H. santamartae in the number of su-praneurals, caudal peduncle depth, head length and orbital diameter.