THE GROWTH, DEVELOPMENT AND REPRODUCTION OF A DEEP-SEA CUMACEAN (CRUSTACEA, PERACARIDA)

A single sample of over 1000 individuals of Leucon jonesi Bishop, 1982, taken at a depth of about 1500 m on the continental slope off Surinam, was studied. The carapace length of individuals in the 1st postmarsupial instar was already about half that of brooding females. Growth increments at early moults were of 20-25%. Males reached the final morphological form in the 6th postmarsupial instar. A prepuberty molt was recognized between the 3rd and 4th male instars. Females reached the preparatory stage in the 4th postmarsupial instar. Brooding condition occurred for the 1st time after the next molt. The brooding form could then alternate at successive molts with an interbrood form, resembling the preparatory female, with small non-overlapping oostegites. Preparatory and interbrood females were morphologically separable; vitellogenesis was restricted to these instars. Broods were of 6-12 young. The individuals in each brood probably completed marsupial development, and were released, one by one. The copepod parasite Sphaeronella infested 10% of brooding-form females.