Reassessment of the Early Cretaceous non-marine ostracod genera Hourcqia Krömmelbein, 1965 and Pattersoncypris Bate, 1972 with the description of a new genus, Kroemmelbeincypris

Abstract

The Early Cretaceous non-marine ostracod genera Hourcqia Krömmelbein and Pattersoncypris Bate are reinstated. A previously published referral of Hourcqia to Cypridea Bosquet is rejected due to the absence of an anteroventral rostrum in the holotype of the type species Hourcqia africana Krömmelbein. The genus Hourcqia is characterized by an “inverse” valve ratio (right valve larger than left) and the lack of an anteroventral rostrum, and the diagnosis of the genus is broadened to accommodate ornamented forms, resulting in the acceptance of five species: Hourcqia africana, H. confluens (Krömmelbein and Weber), H. kouilouensis (Grosdidier), H. bateke (Grosdidier) and H. sylvesterbradleyi (Bate). The previously published synonymy of Pattersoncypris with the genus Harbinia Tsao is also rejected. The diagnosis of Pattersoncypris is refined, meaning that three species are recognized: Pattersoncypris micropapillosa Bate, P. salitrensis (Krömmelbein and Weber), and P. sinuata (Krömmelbein and Weber). The new genus Kroemmelbeincypris is erected for two species initially assigned to Hourcqia, and subsequently to Pattersoncypris and Harbinia by different authors: Kroemmelbeincypris symmetrica (Krömmelbein and Weber) and K. angulata (Krömmelbein and Weber). The genus Hourcqia is diagnostic of latest Barremian non-marine settings, whilst Pattersoncypris and Kroemmelbeincypris characterize Aptian saline lacustrine environments. The geographic ranges of all three genera are restricted to northeastern and eastern Brazil and northern and western Africa, though a species of Pattersoncypris (P. dakotaensis Tibert and Colin) is also present in the United States.