Comparative morphology and classification of South American cynopoeciline killifishes (Cyprinodontiformes: Aplocheilidae), with notes on family-group names used for aplocheiloids

Abstract

A comparative morphological study involving all cynopoeciline killifishes indicates that Leptolebias marmoratus is more closely related to species of the genera Campellolebias and Cynopoecilus than to other species of Leptolebias, and that Mucurilebias leitaoi is the sister group of a clade comprising all other cynopoecilines. Leptopanchax, new genus, is described to place species that share urogenital papilla in males separated from the anal-fin origin by broad interspace, basal portion of the urogenital papilla in males not forming a pronounced wide structure, absence of thickened tissue on the basal portion of the anal fin in males, caudal fin oval and symmetrical in males, anterior proximal radials of the anal fin not placed in close proximity in males, presence of a broad iridescent golden stripe on the distal zone of the dorsal fin in males, and caudal fin with vermiculate dark red marks in males. Poecilopanchax, new subgenus of Cynopoecilus, is diagnosed by having the basihyal narrow, about rectangular, the interarcual element of the dorsal branchial arch ossified, the uncinate process of the third epibranchial distinctively widened, a long filamentous ray on the tip of the anal fin in males, caudal fin lanceolate in males, dark bars on the flank in females, branchiostegal region with intense red pigmentation in males, a brownish red stripe on the basal portion of the dorsal fin in males, and dark red marks extending to the antero-distal margin of the dorsal fin in males. This study follows an old classificatory scheme in which all aplocheiloids are placed in a single family, the Aplocheilidae.