Systematics of Poecilia mexicana (Pisces: Poeciliidae) in Northern Mexico

Abstract

Two distinct subspecies of Poecilia mexicana occur in the northeastern and east-central Gulf coastal drainages of México. P. m. limantouri, the northern subspecies, ranges from the Río Grande drainage in Nuevo León south to the lower Río Tamesí near Tampico. It is a slender, terete form with a short dorsal fin and narrow caudal fin. P. m. mexicana occurs along the Gulf coast from the Río Cazones drainage at least to the greater Río Jamapa system south of Veracruz City. It is a deep, somewhat compressed form with a long dorsal fin and broad caudal fin. A zone of intergradation extends coastwise from the lower Río Soto la Marina of Tamaulipas to the Río Tuxpan of northern Veracruz and inland along the southern drainage basin of the Río Pánuco.