Diversity of seaweeds of the coast of Veracruz, Mexico

Background and Aims: The first records of benthic marine algae for the Veracruz coast date back to 1846; after 114 years, Mexican phycologists restarted their study. There are 312 species recorded for this area. Considering this species richness, as well as the taxonomic modifications and updates that these groups have had, the aim of this work was to present a list of the identified seaweeds organized by taxonomic categories and with data on distribution, temporality and new records for the study area. Methods: Ninety-two samplings were carried out over a period of 18 years, at the intertidal level in 11 localities on the Veracruz coast. Previous records from 1960 to 2020 were also obtained through a bibliographic revision and the phycological collection of the ENCB herbarium was reviewed as well. The nomenclatural status of each species and the classification system were reviewed. The alpha diversity for each locality was calculated with the Shannon-Wiener index; a clustering analysis was also performed using UPGMA with the PAST program. Key results: The phycofloristic list includes 316 species of benthic marine algae distributed in 3 Phyla, 6 classes, 31 orders, 60 families and 130 genera. Each species includes distribution on the Veracruz coast, reproduction, seasonality, habitat, observations, bibliography and ENCB herbarium catalog number. The alpha diversity analyzes show that the greatest diversity is in localities with predominantly rocky substrate with 180 species. The summer rains recorded a high number of species (269); Barra de Cazones has the highest number with 181 species, 70 new records were found for the Veracruz coast; with this the number of taxa increased to 391. Conclusions: The list reveals a higher specific richness of marine algae compared to that reported in Yucat & aacute;n, Campeche, and Tabasco. The phytogeographic affinity of the algae of the Veracruz coast is mixed, since tropical and Caribbean taxa converge there. Constant monitoring is necessary to determine changes in the algal community to establish conservation and use programs.