A REVISION OF THE EASTERN PACIFIC SPECIES OF THE GOBIID FISH GENUS CHRIOLEPIS (TELEOSTEI: GOBIOIDEI) (MEXICO, LATIN AMERICA).

Abstract

This study presents the first partial systematic revision of the speciose American seven-spined gobiid fish genus Chriolepis, which occurs in sublittoral reef-rock and rubble cryptobenthic habitats in tropical-subtropical, primarily insular, waters of the eastern Pacific and western Atlantic oceans. Although a few of the (more poorly known) western Atlantic species are briefly discussed or mentioned, this study focuses on eight eastern Pacific species, representing the majority of the known forms. These populations are disjunctively distributed in the Panamic Province from the Gulf of California, Mexico, southward to Costa Rican (Coco)-Colombian (Malpelo)-Equadorian (Galapagos) oceanic islands lying near or on the equator. This study offers a key to the species, diagnoses of the genus and two subgenera (Chriolepis and Eleotriculus), and diagnoses and descriptions of each species, including the type species and four new forms. The diagnoses and descriptions are based on external morphological study of all known specimens (including statistical analyses of several morphometric characters) and include data derived from recently collected material for the majority of the species. Also provided are illustrations of each species, their geographical and bathymetric distributions, discussions of their zoogeography and postulated evolutionary relationships, and notes on what little is known of their ecology. The highly sedentary behavior of these secretive fishes, coupled to habitat selection with small body size permitting tight-crevice and rock-interspace inhabitation, has favored morphological adaptation (e.g., loss of pelvic-fin fusion and head canal pores) as well as spatial isolation and genetic divergence within the sublittoral cryptobenthic ecotopes inhabited by these gobies in the eastern Pacific. Exploitation of such ecotopes evidently has produced a remarkable degree of convergent evolution between the American seven-spined genus Chriolepis (and its close allies) and several forms of six-spined gobiids found in similar habitats in the Old World.