Termites are small insects that live in colonies and have distinct castes and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattodea (along with cockroaches). Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from cockroaches, as they are deeply nested within the group, and the sister group to wood eating cockroaches of the genus Cryptocercus. Previous estimates suggested the divergence took place during the Jurassic or Triassic. More recent estimates suggest that they have an origin during the Late Jurassic with the first fossil records in the Early Cretaceous. About 3,106 species are currently described, with a few hundred more left to be described. Although these insects are often called "white ants" they are not ants, and are not closely related to ants.