The species of Isoptera (insecta) from the Early Cretaceous Crato Formation: A revision

摘要

The termite species from Brazil's Early Cretaceous (Aptian-aged) Crato (Santana) Formation are evaluated on the basis of the degree of character variation seen in modern species, using a series of 56 specimens, scanning electron microscopy of minute structures, and a bivariate plot of the proportional sizes of sclerotized body structures. Of the previously described species only the following are considered valid: Mariconitermes talicei Fontes and Vulcano, Meiatermes araripena Krishna, Cratomastotermes wolfschwenningeri Bechly, Cratokalotermes santanensis Bechly. and Cretarhinotermes novaolindense Bechly. The combination M. araripena Krishna (once placed in Cretatermes) is restored, and Cretatermes pereirai Fontes and Vulcano is proposed as a junior synonym of M. araripena. The following new species is described: Meiatermes hariolus Grimaldi, new species. The following are considered nomina dubia based on superficial and even contradictory diagnoses: Caatingatermitinae Martins-Neto et al. (likely synonymous with Hodotermitinae); Araripetermes nativa Martins-Neto et al. (nomen incorrectum, recte: nativus), Caatingatermes megacephalus Martins-Neto et al., and Nordestinatermes obesa Martins-Neto et al. (nomen incorrectum, recte: obesus). These are probably all new synonyms of the Cretaceous genus Meiatermes Lacasa-Ruiz and Martinez-Delclos and of M. araripena in particular, but. this assertion cannot be verified without access to the type specimens. Of the six definitive species of Crato termites, reconstructions are provided for four. All species appear to be basal taxa, either a stem group to Isoptera, to Hodotermitidae sensu lato, or to Kalotermitidae. Despite very partial preservation, Cretarhinotermes appears to be within the hodotermitid grade and riot a rhinotermitid. Some specimens have yielded detailed preservation of soft internal tissues, including the midgut, which has further phylogenetic implications.