In a message dated 5/16/2000 6:15:23 AM Pacific Daylight Time, tholtz@geol.umd.edu writes: > In any case, given that herrerasaurids and _Saturnalia_ each have at best a > semi-perforate acetabulum, a fully perforate condition may have arisen > independantly in theropods and sauropodomorphs _Guaibasaurus_ has a semi-perforate acetabulum as well. Nick P.