Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications

The Sarawak swellshark, Cephaloscyllium sarawakensis, has a new mode of oviparity named “sustained single oviparity”, characterized by retention of a single egg case in each oviduct until the embryo attains a sizable length. It may allow them to reach maturity sooner than larger species in a shorter time framed. It is crucial to a species produce a certain number of offspring to maintain a sustainable population and a low fecundity could be a serious disadvantage for a species.

Nakaya K, White WT, Ho H. (2020) Discovery of a new mode of oviparous reproduction in sharks and its evolutionary implications. Sci Rep 10, 12280. https://doi.org/10.1038/s41598-020-68923-1