A new species of Digenea (Rhodomelaceae, Ceramiales) based upon a molecular assessment and morphological observations of plants historically known as D-simplex in Bermuda

Using mitochondrial COI-5P as a barcode marker, the red algal species previously identified as Digenea simplex in Bermuda is shown to be distinct from this species found in the Adriatic (type locality) and Mediterranean Seas, as well as other tropical locations worldwide. This finding led to a comparative study of the morphology of Bermuda specimens and D. simplex from the type locality, as well as other congeners. Our data show the Bermuda specimens to be morphologically, as well as genetically, distinct from D. simplex necessitating the description of D. arenahauriens sp. nov. for plants found in the islands and a single collection from the Caribbean Sea. It represents the first species partitioned from the pantropical D. simplex and we present genetic evidence of additional undescribed isolates in the species complex requiring further study.