Species richness and biogeographical affinities of the marine molluscs from Bahía de Chamela, Mexico.

For more than 10 years (2007-2018), the benthic macroinvertebrates of Bahía de Chamela (Mexican Pacific) were sampled at 31 sites (0-25 m depth). A total of 308 species of the five main classes of benthic molluscs were obtained (106 bivalves, 185 gastropods, 13 polyplacophorans, two scaphopods and two cephalopods). This is a significant increase in the number of species (246 new records) compared to the 62 species previously recorded more than 10 years ago. The distribution in the 31 localities of the bay is given for the first time for most of the species, together with information on its ecological rarity (incidence in the samples). Two families of bivalves (Veneridae and Mytilidae) and three families of gastropods (Calyptraeidae, Muricidae and Collumbellidae) comprised ~ 30% of all species. Ecological rarity was evident with 45 families (45.0%) with only one species and 178 species (57.8%) collected in one site and 67 (21.8%) in two sites. The molluscs of Bahía de Chamela represent 12.2% of all species recorded in the Mexican Pacific. Their biogeographic affinities are mostly related to the Tropical Eastern Pacific (TEP) including the oceanic islands and a few are restricted to the Tropical Mexican Pacific (TMP). Some have broader distributions to adjacent northern and southern temperate regions of the American Pacific, one to the western Atlantic, two pantropical (PAN) and two cosmopolitans (COS). The range distribution of each species was reviewed and updated, thus finding that seven species have extended their ranges of geographic distribution.

Annotated checklist of marine fishes from the Sanctuary of Bahía Chamela, Mexico with occurrence and biogeographic data.

An annotated checklist of marine fishes of the Sanctuary of Islands and Islets of Bahía Chamela in the central Mexican Pacific is presented. Records of fish species were obtained by different methods including visual census, sampling with anesthetics, fisherman-nets, and trawling with a biological dredge. Additional records were obtained from natural history collections and publications. The list comprises 196 species in 64 families and 141 genera. The Carangidae is the most speciose family with 11 species, followed by the Labridae with 10 and the Pomacentridae with nine. Fourteen species are endemic in Mexican Pacific waters, but none is restricted to Bahía Chamela. The most dominant species recorded during underwater surveys were Epinephelus labriformis, Stegastes flavilatus, and Halichoeres dispilus. Most species are of tropical affinities distributed throughout the tropical eastern Pacific (123), eastern Pacific (23), and Mexican Pacific (14). Other species are known from the eastern and Indo-Pacific regions (18), eastern Pacific and western Atlantic oceans (2), and some are circumtropical (9). A new record of the Gulf Brotula Ogilbia ventralis is provided for the Bahía Chamela and its geographical distribution is extended to Mexican central Pacific.