Alveolinids from the Lower Indus Basin, Pakistan (Eastern Neo-Tethys): Systematic and biostratigraphic implications

The alveolinid group of larger benthic foraminifera has been vastly studied in western and central Neo-Tethys, but less well analysed in eastern Neo-Tethys. In this study, 19 Ypresian (Ilerdian-Cuisian) and Early Lutetian species of Alveolina have been identified and their biometrics, taxonomy, and biostratigraphic correlation with western and central Neo-Tethys discussed. The Taxa of Early Ypresian age (SBZ5-9) includes Alveolina vredenburgi, A. dedolia, A. subpyrenaica, A. cf. subpyrenaica, A. moussoulensis, A. aragonensis, A. decipiens, A. cylindrata, and A. ilerdensis. The Late Ypresian age (SBZ10-12) taxa includes A. ruetimeyeri A. oblonga, A. haymanensis, A. lehneri, A. cosinensis cosigena, A. aff. frumentiformis, A sp. aff. A. azzarolii, and A. elliptica. The Early Lutetian age (SBZ13) taxa include A. stercusmuris and A. keili. The identified species have a close affinity to those reported from other areas of the Tethyan realm. However, some of these Alveolina species are considered to have stratigraphic ranges longer than formerly reported. The first appearance of A. ilerdensis (SBZ8-10) is recorded earlier in SBZ7. The first appearance of A. ruetimeyeri (SBZ10-11) is recorded earlier in SBZ-9. The study provides more evidence for understanding the evolution of the Alveolina species and their biostratigraphic distribution in the eastern Tethyan realm.

Automated summary

This study focused on the analysis of the Alveolinid group of larger benthic foraminifera in the eastern Neo-Tethys region, identifying and discussing 19 species from the Ypresian and Early Lutetian ages. Their biometrics, taxonomy, and biostratigraphic correlation with the western and central Neo-Tethys were examined, providing further evidence for understanding the evolution and distribution of Alveolina species in the Tethyan realm.