Appendix: species list for the Crato Formation David M. Martill, G¨unter Bechly and Sam W. Heads
Arachnida Araneae Araneomorphae Araneoidea Familia incertae sedis Cretaraneus Selden, 1990 Cretaraneus martinsnetoi Mesquita, 1996 Mygalomorphae Dipluridae Diplurinae Cretadiplura ceara Selden in Selden et al., 2006 Dinodiplura ambulacra Selden in Selden et al., 2006
Chelonethi = Scorpiones Chactoidea Chactidae Araripescorpius ligabuei Campos, 1986 Scorpionoidea Hemiscorpiidae Hormurinae Protoischnurus axelrodorum Carvalho and Louren¸co, 2001