RESUMEN
Six sediment samples weighing between 224-735 g were collected in June of 2016 from Cayo Nuevo reef, located at the Campeche Bank, southern Gulf of Mexico. Samples were collected by SCUBA diving, from were two stations at depths of 7.6 and 18.2 m. Sediment was sieved and molluscs (adults and micromolluscs ≤ 10 mm) were sorted, examined, and identified to the lowest taxonomic level. A total of 1,347 specimens was found, of which 224 shells were dead and 1,123 were alive. Thirty-four families, 53 genera, and 67 species were identified. The most abundant families were Chamidae and Arcidae for the Bivalvia class, and Caecidae and Tornidae for the Gastropoda class. The vertical range of Bentharca sp. was extended.
RESUMEN
This study represents the first comprehensive chiton study from Alacranes Reef, the largest reef system in the Gulf of Mexico. Nine chiton species were found in seven localities within the area, in the intertidal and subtidal to 12 m depth. SEM examination of C. janeirensis, A. hemphilli, T. schrammi and C. floridanus, showed variations in the sculpture and radular teeth morphology when compared to specimens of the same species from Florida Keys, Bahamas and Puerto Rico. The distribution ranges of T. schrammi, L. liozonis and S. floridana are extended into the south-western area of the Gulf of Mexico. Altogether, combining previous literature and the present survey, reports eleven chiton species which have now been recorded within the Alacranes reef area.