Published online by Cambridge University Press: 14 January 2011
Reproduction remains poorly understood in the Onychoteuthidae, with information previously published on only six of the ~25 species, from three of the seven genera. Herein new information is presented for a further five species from four genera: mated and spent females are reported from the genera Onychoteuthis, Onykia, Notonykia and Callimachus, and the morphologies and locations of implanted spermatangia for the species Onychoteuthis meridiopacifica and Onykia aequatorialis are provided. Males of the genus Onychoteuthis are found to implant spermatangia within longitudinal cuts in the female's mantle surface, while males of Onykia implant individual spermatangia into the female's mantle at various locations, without a specific associated wound. These different implantation strategies are discussed in the context of mating and fertilization. A bulb-like structure at the aboral end of the spermatangium, possibly unique to the genus Onychoteuthis, is also described and examined and its function discussed. All onychoteuthids examined herein are observed to undergo extreme late-life physical degeneration.