TAXONOMY AND ECOLOGY OF THE GENUS
 CHASMODES (PISCES: BLENNIIDAE)
 WITH A DISCUSSION OF ITS ZOOGEOGRAPHY
 JEFFREY T. WILLIAMS'

SYNOPSIS: The western Atlantic blenniid fish genus Chasmodes is represented by two species,
C. bosquianus and C. saburrae. C. saburrae is the more tropical of the species and is found on
Florida's east coast from Edgewater southward around the tip of Florida, northward and
westward to the Chandeleur Islands, Louisiana. C. bosquianus is composed of two subspe-
cies, C. b. bosquianus and C. b. longimaxilla new subspecies. C. b. bosquianus is distributed
on the Atlantic seaboard from Maryland to Marineland, Florida, and C. b. longimaxilla occurs
in the northern Gulf of Mexico from Pensacola, Florida, to Veracruz, Mexico.

 Chasmodes bosquianus longimaxilla exhibits character displacement in the zone of sym-
patry with C. saburrae in the Gulf. Increased maxillary length in this area may be contributing
to the divergence of the disjunct populations of C. bosquianus.

 The zoogeography of the genus Chasmodes is discussed and recent geological information
is used in a consideration of the events leading to its present distribution.
 Experimental hybridization experiments were performed with Chasmodes saburrae and C.
b. longimaxilla, but lack of adequate facilities prevented rearing the larvae.

RESUMEN: El g6nero Chasmodes de peces bleniidos del Atlantico Occidental esta represen-
tado por dos species: C. bosquianus y C. saburrae. C. saburrae es la mas tropical de las
species y se encuentra en la costa este de Florida, desde Edgewater hasta el extreme sur de
Florida; y hacia el norte y este hasta las Islas Chandeleur, en Louisiana. C. bosquianus se
compone de dos subespecies: C. b. bosquianus y C. b. longimaxilla.
 C. b. bosquianus se distribuye cerca a las costas atlanticas desde Maryland a Marineland,
en Florida; y C. b. longimaxilla se distribuye en la parte norte del Golfo de Mexico, desde
Pensacola en Florida, hasta Veracruz en M6xico.
 Chasmodes bosquianus longimaxilla exhibe desplazamiento de caracteres en la zona de
simpatria con C. saburrae en el Golfo de Mexico. El aumento de longitud maxilar en esta area
podria contribuir a la divergencia observada en poblaciones disyuntivas de C. bosquianus.
 Se discute la zoogeografia del genero Chasmodes; asi como informaci6n geol6gica
reciente al considerar los events que conducen a su actual distribuci6n.
 Se Ilevaron a cabo experiments de hibridaci6n utilizando Chasmodes saburrae y C. b.
longimaxilla, pero debido a la falta de facilidades adecuadas las larvas no pudieron ser criadas
con exito.
 TABLE OF CONTENTS
 INTRODUCTION .............................. .................... 66
 ACKNOWLEDGEMENTS ................ .. ......................... 67
 METHODS ................... .................. ....................... 68
 GENUS CHASMODES ................... .................... ................ 69
 KEY TO THE SPECIES AND SUBSPECIES OF CHASMODES.....................70


 The author is with the Division of Fishes, National Museum of Natural History, Smithsonian Institution, Washington, D.C.
 20560. The study was begun at the University of South Alabama, Mobile, and completed at the University of Florida,
 Gainesville, in partial fulfillment for the degree of Master of Science.
 WILLIAMS, JEFFREY T. 1983. Taxonomy and Ecology of the Genus Chasmodes (Pisces:
 Blenniidae) with a Discussion of Its Zoogeography. Bull. Florida State Mus., Biol. Sci. 29(2):
 65-101.