Lake sharks of Triassic Kyrgyzstan

Several 230-million-year-old teeth and egg capsules uncovered at a fossil site in southwestern Kyrgyzstan suggest hundreds of young sharks once congregated in a shallow lake, a new study says.
Called hybodontids, the animals were likely bottom feeders, like modern-day nurse sharks.
Mothers would've attached their eggs to horsetails and other marshy plants along the lakeshore. Once born, the Triassic-era babies would've had their pick from a rich food supply of tiny invertebrates, while dense vegetation offered protection from predators.

Image (showing a beautiful fossil egg case) and information from National Geographic.