Marsupium morphology and brooding biology of the Antarctic giant isopod, Glyptonotus antarcticus Eights 1853 (Crustacea, Isopoda, Chaetiliidae)

Abstract

The marsupium of the Antarctic giant isopod, Glyptonotus antarcticus Eights 1853, has unique characteristics. It deviates in its proportions and construction from the so called Idotea type of brood pouch found in other marine isopod species; some features even remind you of the so called Porcellio type of marsupium which is typical of terrestrial isopods. Details are described by scanning electron microscopy. From our observations and from reviewed data, we suggest that, during the prolonged incubation of brood, adelphophagy contributes to the nourishment of the developing young, and assume that additional nutrition is provided by maternal secretion. These suggestions would partly explain marsupial conditions in G. antarcticus as an adaptation to slow development in an adverse environment. Two species of epizoa, a turbellarian and a fish leech, were found to occur on G. anarcticus in the vicinity of the marsupium.