Reproduction in the Western Pygmy-Possum, Cercartetus-Concinnus (Marsupialia, Burramyidae), With Notes on Reproduction of Some Other Small Possum Species

Abstract

The patterns of breeding and reproduction in Cercartetus concinnus were investigated through the histology of specimens in Australian museums, field observations in north-western Victoria, and published accounts. Histology of the reproductive tracts of museum specimens of female C. nanus, C. lepidus, Acrobates pygmaeus and Distoechurus pennatus was also undertaken to elaborate on reproduction in these species. Young of C. concinnus are born in most months, and some reproductively active males are probably present at all times of the year. Embryonic diapause occurs during the unilaminar blastocyst stage of embryonic development; the blastocysts expand slowly during diapause. The presence of embryos in the uteri of lactating female D. pennatus and C. lepidus suggests that diapause is also probable in these species. The gross anatomies of the female reproductive tracts of the five small possum species are described. Cercartetus spp. have a vaginal system characterised by voluminous culs-de-sac, and only vestigial remains of a median septum. This contrasts with the condition in the two acrobatids, in which the vaginal culs-de-sac are smaller and divided by a prominent septum. The male reproductive anatomy of C. concinnus is similar to that of C. lepidus. The prostate is carrot-shaped and its internal structure is unlike that described for other marsupial groups.