TAXONOMIC RE-EXAMINATION OF THE LATE CRETACEOUS PLANKTONIC FORAMINIFERAL SPECIES ARCHAEOGLOBIGERINA CRETACEA (D'ORBIGNY, 1840) AND CONSTRAINTS ON ITS MORPHOLOGIC VARIABILITY AND STRATIGRAPHIC DISTRIBUTION IN ONE OF THE TYPE LOCALITIES (KENT, SE ENGLAND)

Distinctive and taxonomically relevant morphological differences exist between the original drawings of Archaeoglobigerina cretacea illustrated by d'Orbigny (1840) and the lectotype designated by Banner & Blow (1960), particularly regarding the equatorial periphery, which is rounded in the former and double-keeled in the latter specimen. Such differences would suggest that they are not conspecific, but this hypothesis cannot be easily tested because d'Orbigny's drawings likely represent a synthesis of observations on several specimens rather than a single individual and the slide intended to contain the lectotype is empty. In this study, we have re-examined the A. cretacea type specimens deposited in the d'Orbigny collection at the Museum National d'Histoire Naturelle in Paris and samples from one of the type localities (Kent, SE England) with the aim to reconstruct d'Orbigny's species concept, clarify its morphological features, and better constrain its stratigraphic distribution.