DNA analysis of the lectotype specimen of Ulva nematoidea Bory (Ulvaceae, Chlorophyta) determines its synonymy with Ulva lactuca L.

Ulva nematoidea Bory is a currently accepted species distributed in the south eastern Pacific Ocean from Mexico to Chile. Its identity however remains unknown because no DNA sequences have been obtained from the type specimen. To determine its identity and taxonomic status, we performed high-throughput sequencing on a fragment of the lectotype specimen of U. nematoidea. Genetic analyses of the rbcL, tufA and nuclear ITS DNA found that U. nematoidea is identical in sequence to U. lactuca L. These results indicate that U. nematoidea is a synonym of U. lactuca and further highlight the need for sequencing additional type specimens of Ulva L.