VERMECTIADIDAE, A NEW PRIMITIVE ASELLOTE ISOPOD FAMILY WITH IMPORTANT PHYLOGENETIC IMPLICATIONS

ABSTRACT Vermectiasnelladanae, new species, is described from subantarctic Macquarie Island. It differs in minor details from its only congener, V. caudiculata Sivertsen and Holthuis, 1980, from Tristan da Cunha. Vermectias is the only asellote with 3 free pleonites in front of the pleotelson. Other characters considered primitive within the Asellota are: lateral penes arising from the base of the protopod of pereiopods 7; pointed male pleopod 2 stylet with a broad, open lateral sperm groove; female oopore and cuticular organ opening separately but in a common midlateral pleural groove; cuticular organ and spermatheca derived from a small, discrete cuticular pit in pereionite 5, such pits being present in pereionites 5-7 in all life stages of both sexes. Vermectias is removed from the Janiroidea and a new family, Vermectiadidae, is erected. The new family is not placed in any of the existing superfamilies, pending a reevaluation of asellote phylogeny in the light of character polarities proposed here. Angeliera Chappuis and Delamare Deboutteville, 1954, is removed from the Janiroidea (Microparasellidae) because male pleopods 1 and 2 do not conform with the derived state characterizing that superfamily and because the penes arise from a lateral position close to the base of pereiopods 7. Male pleopods 1 and 2 in Angeliera are similar to those in Vermectias. Further analysis of the placement of Angeliera is outside the scope of this study. The genus is left as incertae sedis.

Affiliations: 1: (JJ) Australian Biological Resources Study, GPO Box 636, Canberra, ACT 2601, Australia;; 2: (GCBP) Department of Crustacea, Museum of Victoria, Swanston Street, Melbourne, Victoria 3067, Australia.