The ovaries of the smooth lumpsucker are characterized by the absence of sperm in all gonads, indicating gonochorism, oviparity
, and external fertilization (Devlin and Nagahama, 2002).
'Grass snake exploit anthropogenic heat sources to overcome distributional limits imposed by oviparity
Heisermann, "Regulation of vitellogenesis in reptiles: correlations with oviparity
and viviparity," in Proceedings of the 9th International Symposium on Comparative Endocrinology, Current Trends in Comparative Endocrinology, pp.
Researchers from the University of Exeter and the University of Lincoln investigated the hypotheses that historical invasions of cold climates by Liolaemus lizards - one of the most diverse groups of vertebrates on earth - have only been possible due to their evolution to viviparity (live birth) from oviparity
Members of the genus Bythaelurus variably display retained oviparity
, probably giving birth to live young with egg capsules observed in utero being described as thin, fragile bags (eg.
Great differences may be observed, from oviparity
to aplacental viviparity, so that it is difficult to use similar techniques for all of them (Demski, 1990).