 They occupied a variety of niches despite relatively low species diversity, including both demersal (bottom-dwelling) species like hupehsuchians and nasorostrans, and pelagic (open-water) species like ichthyopterygians.Many ichthyosauriforms from the Early and Middle Triassic had molariform teeth (shown in the phylogenetic tree above), including "Cartorhynchus"; such teeth indicate a diet at least partially based on hard-shelled animals.In 2020, Huang and colleagues performed an ancestral state reconstruction of teeth among ichthyosauromorphs.