Molecular phylogeny of Neocalanus copepods in the subarctic Pacific Ocean, with notes on non-geographical genetic variations for Neocalanus cristatus

Monophylies of Neocalanus cristatus, Neocalanus plumchrus and Neocalanus flemingeri were revealed by nucleotide sequences of mitochondrial 16S rRNA gene (410 bp) but not of nuclear 18S rDNA gene (1802 bp). Intraspecific variations in mitochondrial 16S rRNA of N. cristatus collected from geographically distant regions were very low (<0.5%).