| Four species in the red algal family Ceramiaceae (Ceramiales) have been described in the phycological literature as being widespread in distribution. Instead, the present study based on comparative vegetative morphology, an examination of historical specimens, and molecular evidence inferred from chloroplast-encoded rbcL, or nuclear LSU rDNA and SSU rDNA sequence analyses, points to the opposite. Centroceras clavulatum, described from Peru, is restricted to that country, northern Chile, southern California, and southeastern Australia; at least five additional species go under the name C. clavulatum: two are new to science, three are resurrected from synonymy, and three more species from South Africa are undescribed. Spyridia filamentosa, described from the Adriatic Sea, is restricted to that region, east and west Florida, the Caribbean Sea, California, Australia, Hawaii, or, alternatively, from the Mediterranean Sea, the western and eastern Atlantic Ocean, and Pacific Panama. Five well-supported clades each encompass distinct species that are likewise either new or validly described taxa that were placed in synonymy under that name. Spyridia hypnoides, described from Cape Comorin in South India, is restricted to the Indian Ocean with one more species distributed in the western and eastern Atlantic Ocean. Antithamnion pectinatum is restricted to New Zealand, and is distinct from A. hubbsii from California and from A. nipponicum from Japan, which are conspecific taxa. The distribution of A. nipponicum is extended to California, Atlantic North Carolina, and the Mediterranean Sea; historical reports suggest that A. nipponicum was recently introduced from Japan. It has become apparent that many species referred to in the literature as "cosmopolitan" have in fact a more restricted distribution, and that the term "cryptic" species is incorrect as applied to these taxa. |
