Gastropods (Mollusca) of the priority marine region to conserve biodiversity No. 31 “Tlacoyunque”, Mexico, associated with the rocky intertidal

Mexico has 70 priority marine regions to conserve biodiversity, three located in the state of Guerrero and have large areas with rocky intertidal, which is one of the most structurally complex and diverse habitats in the marine environment. This research examined ecological characteristics of gastropods, which inhabit the rocky intertidal zone of the Marine Region 31, considering richness, abundance, local geographic distribution, hierarchical distribution, species diversity, and the similarity between sites. Gastropods collected in 2015, 2016, and 2018 were analyzed in nine sites. Per site, an area of 10 m2 was sampled. 103 species were identified. An inventory completeness of 78.41 % to 89.40 % was estimated. In five families, 52.42 % of the species richness and 84.8 % of the abundance were estimated. Nine species are new records for Guerrero. The value of H' was 4.57 bits/individuals and J' was 0.684. 38 species were dominant and 53 occasional. This research reports the greatest richness of gastropods in the rocky intertidal zone of Marine Region 31, increasing the list from 216 to 236 species. Sites with a more heterogeneous habitat, greater stability, and less exposure to waves showed greater richness, diversity, and abundance. Therefore, they must be prioritized for the protection and conservation of the biodiversity and ecosystem.