Artículo de publicación WOSThe systematics of the comb-fin squid species is problematic and poorly resolved. In total, 53 specimens of comb-fin squids (Chtenopteryx spp.) were caught at depths ranging from 30 to 800 m off the Canary Islands (NE Atlantic Ocean). Mantle lengths of the individuals ranged from 18 to 43 mm and the sample included immature, mature male and mature female specimens. Two species of comb-fin squids, Chtenopteryx canariensis and C. sicula, were identified by combining traditional morphological characters with a molecular analysis of a fragment of the cytochrome c oxidase subunit I (COI) gene. Intra- and interspecific genetic distances and maximum likelihood tree analyses based on COI sequences available from GenBank suggest the existence of at least four species, two from the Pacific and two from the Atlantic Ocean. Our data expand the current geographic range of C. canariensis from the NE to NW Atlantic. In the GenBank database, several sequences of comb-fin squid in different species-specific clades have been attributed only to C. sicula, indicating the possible existence of cryptic species and the need to re-analyse these data.