Higher systematics of scorpions from the crato formation, lower cretaceous of Brazil

Abstract

Several new specimens of Protoischnurus axelrodorum Carvalho and Lourenço and Araripescorpius ligabuei Campos from the Crato Formation, Brazil, are described. The preservation and recognition of new morphological features allows a re-diagnosis of both species and a modification of their familial placement. Protoischnurus axelrodorum is the oldest species belonging to the scorpionoid family Hemiscorpiidae Pocock (= Ischnuridae Simon; = Liochelidae Fet and Bechly) and the first Cretaceous record. It was originally placed in the extinct family Protoischnuridae Carvalho and Lourenço, which is here synonymized with Hemiscorpiidae. Araripescorpius ligabuei, now assigned to Chactidae Pocock, is the first chactoid recorded for the Cretaceous of Brazil. These findings confirm that the lineages of two modern families date back at least to the Early Cretaceous and, considering their current distribution, were probably present before the break-up of the supercontinent Gondwana. Palaeoecological inferences indicate the presence of tropical habitats in the vicinity of the Crato lake/lagoon. © 2007 The Palaeontological Association.