Reclassification of Glomalveolina subtilis as a distinct species within Glomalveolina genus: new record from the Iranian platform in the Central Neo-Tethys

Abstract This study considers Glomalveolina subtilis Hottinger, 1960, to be a distinct species within the genus Glomalveolina , previously grouped with G. lepidula (Schwager, 1883). This species is distinguished by unique morphological and biometrical features, setting it apart from closely related species and establishing it as a significant biostratigraphic marker for the early Ypresian (SBZ6-7) in the central Neo-Tethys. Although first reported from the Iranian platform, it expands the paleobiogeographic distribution of G. subtilis , with earlier records from the western Neo-Tethys (Mediterranean and North African basins) during the early Ilerdian (SBZ5–SBZ6) and from the eastern Neo-Tethys (China) in the middle Ilerdian (SBZ7–SBZ8). The Alveolina biostratigraphy is correlated with the calcareous nannofossil biostratigraphy, placing it in the middle part of the NP10 Zone. This discovery highlights the broader distribution of G. subtilis and its significance in refining biostratigraphic correlations and understanding foraminiferal evolution during the Paleocene–Eocene transition.