Late Cretaceous alveolinaceans (larger foraminifera) of the Caribbean palaeobioprovince and their stratigraphic distribution

摘要

Architectural analysis of the Late Cretaceous alveolinaceans of the Caribbean palaeobioprovince has made it possible to separate four genera: Praechubbina, Chubbinella gen. nov., Chubbina and Caribalveolina. The first three genera belong to the family Rhapydioninidae, while the fourth is placed in the family Alveolinidae. Two species, Praechubbina breviclaustra and P. oxchucensis sp. nov., represent the primitive genus Praechubbina, while the species cardenasensis and obesa, previously ascribed to this genus, must be reassigned respectively to Chubbinella gen. nov. and Caribalveolina. The species Chubbina jamaicensis, C. macgillavryi and C.fourcadei sp. nov. complete the inventory of Chubbina. The alveolinid genus Caribalveolina comprises two species, C. obesa and C. michaudi. Caribbean alveolinaceans include two successive assemblages. The lower assemblage is characterized by Praechubbina oxchucensis, P. brevisclaustra, Chubbinella cardenasensis and Caribalveolina obesa. The upper assemblage is represented by the genus Chubbina, with C. fourcadei, C. jamaicensis and C. macgillavryi, and Caribalveolina michaudi. The age of the lower assemblage is uncertain (probably Late Campanian-Early Maastrichtian), while the upper assemblage has been dated by strontium isotope stratigraphy as Late Maastrichtian.