 Probabilistic methods suggested that rounded or flat teeth most likely evolved independently five times, while methods based on parsimony suggested that they evolved independently three to five times.Huang and colleagues observed that the development of molariform teeth occurred independently many times in aquatic animals (including multiple lineages of monitor lizards, moray eels, and sparid and cichlid fish), and thus the frequency among ichthyosauriforms is not unusually high.They also observed that Early Triassic ichthyosauriforms generally had small, rounded teeth; the teeth of Middle Triassic ichthyosauriforms were more diverse in size and shape, which correlates with increased invertebrate diversity.