Dwarf males of giant warty squid Kondakovia longimana and a description of their spermatophores

摘要

Antarctic squids are widely known to play an important role in the diet of various Antarctic predators, although the biology of those squids and how that relates to their availability to their predators is poorly known. We assessed the reproductive system of the deep-sea giant warty Antarctic squid Kondakovia longimana under a predator-prey context. The spermatophores of male K. longimana are described, based on two specimens foraged by albatrosses at Bird Island, South Georgia (54A degrees S, 38A degrees W). Spermatophore length (SL) was 42-90 mm, head occupied mean = 1.8-2.4% SL, ejaculatory tube = 17-22% SL, cement body = 19-22% SL, seminal reservoir = 56-59% SL and rear empty part = 0.4-0.8% SL. All spermatophores of K. longimana in our study were normal and functional, and very dissimilar to those of other spent squid, in which the spermatophores have short, semi-transparent seminal reservoirs and a large empty rear part. Senescent male K. longimana could become available to predation by albatrosses (presumably being surfaced) with spermatophoric sacs (Needham's sacs) containing at least a hundred of normal spermatophores having no evidence of reproductive system degeneration. From known relation between beak and body size all known adult males in K. longimana were dwarfs in respect to females. Our data also show that they have extended spermatophore production as in other squids.