 During the Triassic and Early Jurassic, hybodontiforms were the dominant selachians in both marine and non-marine environments.A study of Middle Jurassic fossils from England analyzed 20 species from 11 genera suggesting that hybodonts flourished at that time.A shift in hybodonts was seen during the Middle Jurassic, a transition between the distinctly different assemblages seen in the Triassic – Early Jurassic and the Late Jurassic – Cretaceous.