Termite (Insecta: Isoptera) nest ichnofossils from the upper triassic chinle formation, petrified forest national park, Arizona

Abstract

A fossil nest (calie), including chambers and galleries (runaways), from the lower part of the Petrified Forest Member of the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona, is similar to nests constructed by modern primitive termites (Insecta: Isoptera), which reflect cooperation in nest construction typical of complex social behavior. A new ichnogenus and ichno‐species, Archeoentomichnus metapolypholeos, is proposed for the distinctive ichnofossil that may represent the efforts of a social caste system in primitive termites. The Late Triassic (Late Carnian) nest also may represent the earliest known fossil evidence of Isoptera (termites) and is suggestive of the antiquity of social behavior among insects. Social behavior in insects, including termites, was previously thought to have evolved in the Early Cretaceous in conjunction with the evolutionary radiation of angiosperms. Because the fossil and ichnofossil record of insects and organisms suggested to be insects dates back...