Heteropod molluscs (Carinariidae and Pterotracheidae) of the Gulf of México and western Caribbean sea

Abstract

THE DISTRIBUTION, COMPOSITION, AND ABUNDANCE OF CARINARIID AND PTEROTRACHEID HETEROPOD MOLLUSCS WAS ANALYZED FROM 160 ZOOPLANKTON SAMPLES COLLECTED DURING FOUR CRUISES CARRIED OUT IN OCEANIC AND NERITICAREAS OF THE MEXICAN CARIBBEAN SEA AND THE SOUTHERN GULF OF MEXICO. FOUR SPECIES WERE IDENTIFIED, FIROLOIDA DESMARESTI BEING THE MOST ABUNDANT , FOLLOWED BY PTEROTRACHEA HIPPOCAMPUS, CARDIAPODA PLACENTA, AND P. CORONATA. THESE RECORDS REPRESENT OVER HALF THE NUMBER OF SPECIES KNOWN IN THE ENTIRE GULF OF MEXICO AND THE CARIBBEAN SEA. NO DIFFERENCES OF ABUNDANCE OR SPECOES COMPOSITION WERE RECORDED WHEN SPRING AND SUMMER DATA WERE COMPARED IN NERITIC AND OCEANIC WATERS OF THE GULF OF MEXICO. THE OVERALL DENSITY OF HETEROPODS IN THE SURVEYED AREA IS RELATIVELY HIGHER THAN IN OTHER REGIONS. THE FINDING OF PTEROTRACHEA CORONATA IN THE MEXICAN CARIBBEAN SEA REPRESENTS A NEW GEOGRAPHIC RECORD FOR THE HETEROPOD FAUNA OF THE WESTERN CARIBBEAN SEA. A DICHOTOMIC KEY FOR THE IDENTIFICATION OF THE SPECIES RECORDED IN THIS SURVEY IS PRESENTED HEREIN. THIS IS THE FIRST SURVEY OF THE MEXICAN ATLANTIC OCEANIC HETEROPOD FAUNA.