Diversity and environmental implications of Paleocene-Eocene coralline red algae in the eastern Tethys (Meghalaya, northeastern India)

Increasing research interest and application of coralline red algae in case studies pertaining to the reconstruction of Cenozoic shallow-marine environments have made it intriguing to delve deeper into their diversification patterns and evolutionary history. Corallines in the Tethys realm have mostly remained in the shadow of concurrent benthic organisms like corals and larger benthic foraminifera during the dramatic climate regimes of the Paleogene. Factors like sampling bias, taphonomic impacts, and taxonomic constraints associated with the regular morpho-anatomical approaches have been major challenges in the evaluation of fossil coralline algae. Resultantly, their response to the Paleogene hyperthermals and other climatic perturbations are poorly understood. The current work aims to analyze the diversity and environmental implications of coralline algae from multiple Paleocene-Eocene sedimentary successions of Meghalaya, northeastern India. Corallines maintained near persistent levels of generic diversity and abundance, with only Distichoplax being preponderant in the Lakadong Limestone and showing a drastic population collapse in the early Eocene. Manifesting an extensive paleogeographic range worldwide, Sporolithon , Lithothamnion , Mesophyllum , and Lithoporella are the other common genera in the study region, which diversified consistently and were not significantly influenced by the environmental changes.