Aspects of the histology of reproduction in the female Angolan free-tailedbat Mops condylurus (Microchiroptera : Molossidae) in Mpumalanga, South Africa

The reproductive pattern of the female Angolan free-tailed bat Mops condylu rus (A. Smith, 1933) was investigated at two localities in Mpumalanga. Fema le Angolan free-tailed bats displayed a seasonal bimodally polyoestrous rep roductive pattern. Parturition in December was followed closely by a postpa rtum oestrus. Ovarian follicle and endometrium cycles also closely followed the breeding season. The reproductive tract displayed complete dextral dom inance with the right ovary and uterus being functionally dominant. Luteal activity was maintained throughout pregnancy and healthy corpora lutea were observed until late in pregnancy. Shedding of the zona pellucida occurred in the oviduct in the region of the ampulla-isthmus junction. The embryo en tered the uterus as a morula, where it was transformed into a unilaminar, f ree-lying blastocyst. A unique feature of the pre-implantation uterus was t he formation of a distinct decidua at the implantation site on the mesometr ial side. Implantation in the Angolan free-tailed bat was centric and super ficial. First attachment of the trophoblast to the endometrium was mesometr ial. The formation of a pre-placental pad of trophoblast cells was also ini tiated on the mesometrial side, while orientation of the embryonic disc was anti-mesometrial. Placental development occurred in the abembryonic hemisp here. Proliferation of the trophoblast over the embryonic hemisphere was sl ow and a bilaminar arrangement of the trophoblast was not observed in this region until after the primitive streak stage.