The systematics and zoogeography of cephalopods from the Gulf of Mexico.

Sixty-four of the 84 species of cephalopods known to occur in the Gulf of Mexico are described in this report. Seventeen species are reported for the first time from this region, plus four probable new species, among the squid genera of Neorossia, Neoteuthis, and Chiroteuthis, and the octopod genus Grimpoteuthis, are described. Descriptions are given for the adults of Octopoteuthis megaptera (Verrill) and Bathothauma lyromma Chun, for the male of Abralia redfieldi G. Voss, and the hectocotylized state of Brachioteuthis. Synonymies are suggested for Onykia carriboea Lesueur and Mastigoteuthis glaucopsis Chun. Zoogeographic relationships are given for the entire Gulf cephalopod fauna. Several of the deep-sea benthic species appear to be distribution within wide bathymetric zones on the continental slope, and only one species, Grimpoteuthis sp., is found exclusively at abyssal depths.