First record of hybodont egg capsules from the Jurassic of Thailand

Abstract

Two egg capsules of Palaeoxyris sp. are reported from the Jurassic Phu Kradung Formation in the Khorat Plateau, northeastern Thailand. As the record of this genus remains rare in the Jurassic, it complements its stratigraphic distribution. Most importantly, it represents the first unambiguous evidence that some hybodont sharks from the Mesozoic of Thailand were able to reproduce in fresh waters, even if it is not yet possible to identify which species in particular.