Taxonomic study of Hoplias microlepis (Gunther, 1864), a trans-Andean species of trahiras (Ostariophysi: Characiformes: Erythrinidae)

The Hoplias malabaricus species group represents one of the most complexes taxonomical problems in the systematics of Neotropical fishes, including specimens widely distributed in most drainages of South America and part of Central America with great variation or overlap of putative diagnostic characters. The large number of nominal species, many of which without known type material, renders the problem more complicated. Currently, at least three nominal species can be included in the Hoplias malabaricus species group based on the form of the medial margins of dentaries and presence of tooth plates on the tongue: Hoplias malabaricus, H. teres, and H. microlepis, the latter representing the only exclusively trans-Andean known species of the genus. We present herein a taxonomic study of Hoplias microlepis based on examination of syntypes and recently collected specimens, including a redescription of the species. Hoplias microlepis occurs in the Pacific drainages of Panama and Southwestern Costa Rica, in addition to the rio Guayas basin in Ecuador and the region near its mouth (rio Tumbes, Northwestern Peru). Records of the species on the Atlantic coast of Panama are restricted to the Canal Zone, suggesting dispersal through the Panama Canal. We also designate lectotype and paralectotypes.