Algal epibiont species on Chiton articulatus (Mollusca: Polyplacophora) from a rocky intertidal coast from the Mexican Tropical Pacific

Chiton articulatus, a mollusk endemic to the Mexican Pacific, is a species whose ecological associations with the algae that colonize it are not well known. This work describes the epibionts observed on the shells of this species. We collected chitons in the rocky intertidal of 2 localities in the state of Guerrero, Mexico. Sixty-two chitons were collected that had 50 species of algae. The best represented family was Cladophoraceae with 10 species. Of the total number of specimens, 26 had epibionts whose distribution on the shell was different: 11 species on the valves, 17 on the suture, 1 on the belt, and 22 species shared in the first 2 zones. Five morphofunctional groups of algae were recognized: microscopic, filamentous, crustose, foliose and corticated filaments, with a predominance of filaments. A relationship was found between the size of the chitons and the percentage of algal cover. Studies like the present one are important due to the interaction between both organisms, since chitons offer surfaces of easy colonization for algae. Furthermore, records of species that do not commonly appear in floristic inventories can be found on these.