Time to say goodbye: taxonomic revision of Dictyoconus walnutensis (Carsey, 1926), the last Lower Cretaceous representative of the genus.

(Carsey) represents a middle-lower upper Albian orbitolinid marker taxon, endemic to the American-Caribbean realm (Gulf Coast area, Mexico, Venezuela). The species has a number of features incompatible with Dictyoconus Blanckenhorn, namely the presence of a simple and slightly eccentric embryo instead of an initial spire with an embryo that may be septulated, lack of marginal apertures, and a rather simple exoskeleton. Based on the combination of these characteristics, the new genus Carseyella is herein established with the new combination Carseyella walnutensis (Carsey). The upper Aptian Carseyella algeriana (Cherchi & Schroeder) comb. nov. is considered a more primitive representative due to the lack of horizontal partitions in the marginal zone. Dictyoconus once used as a catch-all term for various larger foraminifera of Jurassic to Palaeogene age is now removed from the Early Cretaceous and restricted to the Maastrichtian – Palaeogene. The phylogenetic relationship of the Maastrichtian (D. bakhtiari Schlagintweit, Rashidi & Babadipour) and the Eocene species [e.g., D. egyptiensis (Chapman), D. indicus Davies] requires further clarification. This once commonly used generic name can now be used in a much more precise and stratigraphically restricted sense. [ABSTRACT FROM AUTHOR]