The phyllodocid polychaete
Notophyllum foliosum occurs in two colour morphs in Swedish and Norwegian waters, one palish yellow to grey form with black patches that is restricted to deeper waters and often associated with reefs of the deep-water coral
Lophelia pertusa, and one usually yellow-orange form with black patches and white spots that is usually encountered on more shallow bottoms. We have sampled the two forms from sympatric occurrences in Norway, and the shallow form from the Swedish west coast. Phylogenetic and haplotype analyses based on the mitochondrial cytochrome c oxidase subunit I (
COI) gene and the nuclear internal transcribed spacer region (
ITS1-5.8SrDNA-ITS2) unequivocally indicate that the two forms represent different species. We apply the name
N. foliosum (Sars, 1835) to the ‘shallow form’, and propose
N. crypticum n. sp. for the ‘deep form’. A lectotype is fixed for
N. foliosum.
