New mayflies (Insecta, Ephemeroptera) from the Santana Formation (Lower Cretaceous), Araripe Basin, northeastern Brazil

Abstract

This paper reviews all previous knowledge about ephemerid nymphs from the Santana Formation (Lower Cretaceous, northeastern Brazil) involving the families Hexagenitidae, Siphlonuridae and Oligoneuriidae, represented by nymphs and adult forms. They occur associated with representatives of at least five other ephemerid families, as well as twenty three other insect orders. This is one of the richest and most diverse insect fauna known in the geological record. Five new taxa are proposed, viz. Cratogenites corradiniae gen. n., sp. n., Cratogenitoides delclosi gen. n., sp. n., Palaeobaetodes britoi sp. n., Costalimella nordestina gen. n., sp. n., and Cratoligoneuriella leonardii gen. n., sp. n. The genera Protoligoneuria Demoulin and Palaeobaetodes Brito are reviewed. The palaeontological significance of ephemerid nymphs in the lacustrine complex at Crato Member is discussed, and possible ephemerid provinces are proposed, as well as habitats, as deduced from the material collected.