DEHRADUN: In a landmark discovery that rewrites the geological history of the Himalayan foothills, scientists from the Wadia Institute of Himalayan Geology (WIHG) have unearthed 4.5-million-year-old fish fossils in the Mohand area, near the Uttarakhand border.
This marks the first time aquatic life fossils have been identified in this region, which was previously known only for terrestrial animal remains.
The discovery, which includes ear bones (otoliths) of three distinct freshwater fish species, offers a rare glimpse into the prehistoric ecosystem of the Shivalik range.
"The Shivalik hills are a treasure trove for paleontologists. While we have long studied the area, we predominantly found fossils of land-dwelling mammals. Finding aquatic fossils, specifically ear bones, is a breakthrough that changes our understanding of the ancient environment here," said Dr. Ningthoujam Premjit Singh, a senior scientist at the Wadia Institute, who led the research.
The team identified three species: the snakehead, the goby, and the gourami. The discovery of the gourami (Trichogaster fasciata) is particularly significant; it is only the second time this species has been reported in the global fossil record, with the only previous instance documented in Sumatra, Indonesia.
According to Dr. Singh, these fossils are not just relics; they are indicators of a lost habitat.
"Ecologically, these assemblages suggest that the Mohand area was once a calm, stable freshwater body, likely a lake or a slow-moving river, surrounded by dense vegetation approximately 4.5 to 4.8 million years ago," he explained.
The research process was meticulous, spanning two field seasons. Sharing the methodology exclusively with TNIE, Dr. Singh described the arduous task of uncovering microscopic history.
"During our 2024 and 2025 field seasons, we identified several fossiliferous layers. We conducted bulk sampling and transported large quantity of sediment to the institute. In the laboratory, we washed the samples through different sieves, dried them, and meticulously examined the material under microscopes to isolate the otoliths."
Beyond the fish, the Mohand site continues to yield other biological surprises.
The team previously discovered fossils of the Indian Bush Rat, which belonged to a lineage distinct from modern species, suggesting a high level of prehistoric biodiversity in the region.
This interdisciplinary study was a collaborative effort involving researchers from Panjab University, Chandigarh, the Central University of South Bihar, and the Biodiversity Research Centre at Academia Sinica, Taiwan.
As scientists continue to analyze these findings, the discovery serves as a reminder that the rugged Himalayan terrain holds secrets far older than its towering peaks. T
his research not only sheds light on the aquatic evolution of the region but also provides critical data for understanding how the local environment transitioned over millions of years, potentially unlocking further mysteries buried within the Shivalik strata.