Revision of Syncyclonema (Upper Cretaceous) and comparison with other small pectinid bivalves and Entolium

New descriptions and figures are given for Pecten rigida Hall & Meek ( = Pecten halli Gabb), the type species of Syncyclonema Meek, and for the type species of genera to which Syncyclonema is often compared: Entolium Meek, Eburneopecten Conrad, Pectinella Verrill, Hyalopecten Verrill, Camptonectes Agassiz, Micronectes Ichikawa & Maeda, Pseudamussium Mörch, and Pseudamussium H. & A. Adams. Syncyclonema is shown to be a valid genus. A lectotype is designated for Syncyclonema halli, and on the basis of its chlamyiid shape, deep byssal notch, and hinge morphology Syncyclonema is placed in the family Pectinidae. These characters invalidate synonymy of Syncyclonema with Entolium and its assignment to the family Entoliidae Korobkov

Generic status of the Inoceramus? tegulatus species group (Bivalvia) of the latest Cretaceous of North America and Europe

Five named species of the latest Cretaceous Inoceramus? tegulatus species group are, on present information, considered valid: two from North America, fibrosus (Meek and Hayden) and argenteus Conrad; three from Europe, tegulatus Hagenow, caucasicus Dobrov and dobrovi Jeletzky. The morphology of the ligament area and the pattern of muscle scars differentiate the species from Inoceramus, and Tenuipteria Stephenson is the valid generic name for the broad taxon encompassing the five species. The five species can be divided into two lineages: a lineage of equivalved species (tegulatus, fibrosus, caucasicus) and a lineage of inequivalved species (argenteus, dobrovi). The equivalved species occur in the uppermost Late Campanian, Early Maestrichtian and lowermost Late Maestrichtian, and the inequivalved species appear to be restricted to the Late Maestrichtian. Tenuipteria fibrosa and argentea are redescribed and illustrated, a neotype for argentea is designated, and a lectotype for T. tegulata is designated