Polysiphonia sensu lato (Ceramiales, Florideophyceae) species of Caribbean Panama including Polysiphonia lobophoralis sp nov and Polysiphonia nuda sp nov.

Only two species of Polysiphonia sensu lato (predominately species of Polysiphonia and Neosiphonia) have been reported from Caribbean Panama. In contrast, 16 species are documented from the neighboring countries of Costa Rica and Colombia. Molecular-assisted identification using plastid-encoded ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene (rbcL) and mitochondria-encoded cytochrome c oxidase subunit I gene (COI) loci identified 14 species from 38 samples collected along the Caribbean coast of Panama. Morphological character states were examined and used to identify each sample, and phylogenetic relationships among these species were estimated through maximum likelihood analyses of rbcL and nuclear-encoded SSU sequence data. Neosiphonia ferulaceae, N. tongatensis, Polysiphonia binneyi, P. havanensis, P. macrocarpa, P. pseudovillum, P. schneideri, P. subtilissima, and two species that could only be identified as P. cf. sertularioides are reported for the first time from Panama. Polysiphonia pentamera, a species only known from the eastern Pacific is reported for the first time in the Caribbean, and two new species, P. lobophoralis and P. nuda are described. A key to Caribbean Panama species, descriptions of species morphology and remarks on taxonomy and relationships are provided. These findings demonstrate that previous limited reports of Polysiphonia sensu lato species from Panama resulted from a lack of study, rather than a lack of diversity, within the region.