Phylogenetic analyses of Macaronesian turf-forming species reveal cryptic diversity and resolve <i>Stichothamnion</i> in the <i>Vertebrata</i> clade (Rhodomelaceae, Rhodophyta)

Algal turfs are ecosystem engineers receiving steadily growing attention in recent years relation to their expansion on temperate reefs due global change. However, species diversity and taxonomy still poorly understood, mostly based solely morphological information. the dominant type of assemblage Macaronesia, but molecular surveys have barely been applied this region. We aim show how tools can assist us improve our understanding natural algal by studying turf-forming rhodomelacean genus Stichothamnion which has only one recognized generitype S. cymatophilum. resembles other members tribe Streblocladieae, it unbranched trichoblasts, an unusual character family. Here, we using phylogenetic analyses rbcL gene that specimens collected Canary Islands Azores identifiable morphologically as cymatophilum exhibit cryptic diversity, these position Vertebrata clade with full support. place synonymy Vertebrata, transfer existing species, describe a newly discovered V. barbarae Muñoz-Luque & Díaz-Tapia, sp. nov., found exclusively Azores. The new was indistinguishable from cymatophila diverged 2.1–2.3% gene. This study illustrates work required better understand extraordinary such those Macaronesia remain taxonomically under-studied.