DNA barcoding for squids of the family Gonatidae (Cephalopoda: Teuthida) from the boreal North Pacific.

AbstractA fragment of cytochrome c oxidase I was used to assess whether species of the squid family Gonatidae from the North Pacific could be identified using DNA barcoding approach. Pairwise intra- and interspecific p-distances were assessed, and systematic relationships among species were estimated by NJ analysis. Examined species formed well-differentiated species-specific clades on the neighbor-joining and Bayesian trees. Multiple taxa formed clades supported by both tree topologies and species hypothesis-free ABGD method. Species morphologically identified as Gonatus tinro and Gonatopsis okutanii demonstrated intraspecific level of molecular genetic divergence (0.2–0.3%) indicating that they are conspecific. Genetic differences between the G. berryi clade and a squid morphologically close to that species may indicate a new cryptic species. High levels (>6.2%) of genetic differentiation within B. borealis suggested the existence of two cryptic species. This study confirms the usefulness of DNA barcodi...