Article: The Tethyan bivalve Roudairia from the Upper Cretaceous of California

The Tethyan genus Roudairia is described for the first time from North America. A new species, Roudairia squiresi, occurs in the shallow-marine, basal beds of the San Francisquito Formation (uppermost Maastrichtian) at Warm Springs Mountain, Los Angeles County, California. The earliest representatives of the genus Roudairia are from the Cenomanian of north and west Africa. The genus later migrated westward to the western Tethyan Realm and into California during the latest Cretaceous. The presence of R. squiresi suggests warm water in California at the end of the Cretaceous. The taxonomic status of two closely related genera, Cicatrea and Veniella, in relation to Roudairia, remains unclear. However, among these three related taxa, there are at least two distinct generic groups present. The first is represented by Veniella and the second by Roudairia. Specimens from Africa and Madagascar, previously ascribed to 'Cicatrea' cordialis, belong in the second group. Whether Cicatrea cordialis from India also belongs in this second group cannot be determined until additional specimens provide better morphological data.