THOOTHUKUDI: The marine fossils discovered at Panaiyur in Kulathur South panchayat approximately belong to the middle to late Holocene epoch, i.e., between 8,000 and 12,000 years ago, states a report sent to District Collector Vishu Mahajan by the Zoological Survey of India (ZSI) a week ago.
A team of ZSI scientists, between January 5 and 10, conducted a paleontological survey of the fossil sites in Panaiyur, located nearly 25 kilometres north of Thoothukudi.
In December 2025, archaeology ensthusiast P Rajesh Selvarathi discovered the fossil site, and subsequently the then collector K Elambahavath wrote a letter to the ZSI to undertake a research at the site.
The technical report, ‘Paleontological Assessment of Newly Discovered Fossil Beds in Thoothukudi District’ authored by Dola Roy, Debashree Dam, R Chandran, C Raghunathan and Dhriti Banerjee, stated that the Panaiyur fossil assemblage was assigned the tentative age based on its stratigraphic position, sedimentological context, degree of fossilisation, and comparison with dated quaternary deposits from the region.
The fossil bed represents deposits formed during the Holocene marine transgression, when rising sea levels inundated previously exposed coastal plains and created extensive shallow marine environments suitable for sediment deposition and fossil accumulation, it added.
The site contained marine invertebrate fossils – primarily bivalves and gastropods – embedded in ancient sedimentary formations. While the surface is dominated by quaternary alluvium, coastal and aeolian teri sands and tertiary sediments, the rock surfaces are composed of quartz, feldspar framework, pebble-sized fossils of bivalve and gastropods.
“The continuity of these species from the fossil record to the present demonstrates their resilience and adaptation to the Gulf of Mannar ecosystem,” stated the report.
On the ecological characteristics of the fossil species, the report stated that the assemblage indicated a shallow-marine to estuarine setting with mixed sandy-muddy substrates, moderate water circulation, marine to brackish salinity, and warm tropical temperatures.
The study also delved into coastal evolution and sea-level history, as the position of the fossil locality – 5-7 kilometres inland from the present coastline – provided evidence for changes in coastal configuration during the Holocene that spanned approximately 11,700 years, beginning at the termination of the last glacial period.
Further, the report recommended that the government protect the significant site, and conduct a radiocarbon dating exercise to establish precise depositional ages.
The scientists collected a total of 104 fossil specimens belonging to four taxonomic groups from the phylum Mollusca. Chandran said that the fossil assemblage shows similarity to the modern marine fauna of the Gulf of Mannar, suggesting environmental continuity over Holocene period.