Hybolophus Stewart, 1930

Devries, Thomas J., 2016, Fossil Cenozoic crassatelline bivalves from Peru: New species and generic insights, Acta Palaeontologica Polonica 61 (3), pp. 661-688 : 675

Genus Hybolophus Stewart, 1930

Type species: Crassatella gibbosa Sowerby, 1832 ; original designation; Pacific coast of South America, Recent .

Remarks.— Stewart (1930) equivocated in his description of Hybolophus , focusing finally but with reservations on the opisthogyrate beaks (umbones?) of the new taxon. Thus, Hybolophus is better viewed through the descriptive prism of the type species, H. gibbosus . MacNeil (1936) and Ward and Blackwelder (1987) consequently leaned towards excluding less inflated and less posteriorly produced species that are herein placed in Kalolophus . Similarly, Marks (1951) expressed uneasiness about placing in Hybolophus his early Miocene species from Ecuador, which, being only slightly produced posteriorly and possessing a widely divergent and single posterior ridge, presents a veneriform profile. Marks (1951) would have been uneasier yet if Olsson (1964) had already published accounts of his late Miocene Ecuadorian Eucrassatella picadera and Colombian E. tubera . For now, considering the scarcity of exposed hinge plates and specimens of veneriform crassatellines, it is premature to assign the veneriform crassatellines to a separate genus or subgenus; they are included here within a more broadly conceived Hybolophus .

Stratigraphic and geographic range.—Upper Eocene to Recent, western North and South America, Caribbean.