Quantitative paleobiogeography of the Albian–Maastrichtian bivalves of Ariyalur, south India: Impact of the northward movement of the Indian Plate

• Published in: Journal of Earth System Science 2023-09, Vol.132 (3), p.116, Article 116
• Main Authors: Mukhopadhyay, Arkaprava, Paul, Shubhabrata, Poddar, Arghya
• Format: Article
• Language: English
• Subjects: Affinity; Biogeography; Bivalvia; Cretaceous; Datasets; Earth and Environmental Science; Earth Sciences; Mollusks; Paleobiogeography; Paleobiology; Plates; Sediments; Similarity; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Taxonomy
• ISSN: 0973-774X; 0253-4126; 0973-774X
• DOI: 10.1007/s12040-023-02134-w

The paleobiogeographic affinity of the late Early to Late Cretaceous bivalves of the Cauvery Basin, India, has been debated for decades. While some studies have documented an affinity with the Austral province, others have suggested more similarity with the bivalve fauna of the East African province-subprovince. In the present study, we present an updated dataset of the Albian–Maastrichtian bivalves of the Ariyalur region of the Cauvery Basin. Records of the contemporaneous bivalves from the Austral province and the East African province-subprovince are also compiled from the global database and previous literature. Quantitative analyses suggest that the paleobiogeographic history of the Ariyalur bivalves is more complex than previously thought. Ariyalur bivalves were more similar to the bivalves of the Austral province in the Albian to middle Turonian. However, the paleobiogeographic affinity of the Ariyalur bivalves shifted towards the East African province-subprovince in the middle Turonian to Maastrichtian. This temporal shift is evident in different taxonomic levels and ecological groups. The northward movement of the Indian plate and the associated change in the relative distance between the provinces with the Ariyalur region may explain the observed temporal shift in the paleobiogeographic affinity. Research Highlights An analytical approach, along with an updated dataset, suggests that the biogeographic history of the Late Cretaceous Ariyalur bivalves is more complex than previously reported. While the Ariyalur bivalves show higher similarity with the Austral province in the Albian–mid Turonian (113–91.1 Ma), the paleobiogeographic affinity of Ariyalur bivalves shifted to the East African province-subprovince in the middle Turonian–Maastrichtian (91.1–66 Ma). Analyses at different taxonomic levels and ecological groups with three different similarity indices reinforce the observed shift in faunal similarity. The northward movement of the Indian plate and the change in relative distances between provinces may explain this temporal shift in paleobiogeographic affinity.