Gracilaria microcarpa sp. nov. (Gracilariaceae, Rhodophyta) from the southwestern Gulf of Mexico

Abstract

Abstract Although the genus Gracilaria is well represented on the Mexican coasts, there are few studies focused on the taxonomic aspects and the clarification of the relationships between species. The high morphological plasticity exhibited by several of its representatives could underestimate the true species richness. In the present study, a group of cylindrical specimens of Gracilaria from the southeastern Gulf of Mexico, previously identified as G. cornea, was collected. Based on COI-5P and rbcL sequences, these samples formed an independent group closely related to G. ferox, a flat species. Morphologically, our specimens differed from G. ferox and the other species of Gracilaria by the presence of very small cystocarps and a thick pericarp composed of many layers of cells. We propose Gracilaria microcarpa sp. nov. as the name for this group of cylindrical specimens from the Yucatan Peninsula of Mexico.