Manipur University, 8 July, 2026, Researchers from the Department of Zoology, Manipur University, have discovered two new freshwater mussel species from Manipur, making a significant contribution to the scientific understanding of the region’s aquatic biodiversity, taxonomy and evolutionary history. The research was conducted by Dr. Yambem Tenjing Singh, Prof. Naorem Mohilal Meitei, Samita Sorokhaibam Devi and Dr. Bina Loukrakpam. The study documented the freshwater mussel diversity of Manipur using an integrative taxonomic approach that combined morphological examination with DNA-based analyses.
The research identified six freshwater mussel species belonging to the subfamily Parreysiinae across four genera, namely Indonaia, Lamellidens, Parreysia and Radiatula. Among them, two species have been described as new to science: Indonaia manipurensis sp. nov. and Parreysia imphalensis sp. nov. The study also clarified the taxonomic status of Radiatula theobaldi, an endemic freshwater mussel species of Manipur, based on newly sequenced topotypes. This has provided fresh evidence on the diversity, classification and evolutionary relationships of freshwater mussels in the Indo-Myanmar region.
According to the researchers, Manipur’s freshwater mussel fauna represents a distinctive assemblage of endemic and allochthonous unionid species. This diversity has been shaped by ancient geological and biogeographical processes, including historical connections between freshwater systems of the Indian Plate and the Burma Terrane.
The study’s time-calibrated phylogenetic reconstructions reveal broader biogeographical patterns linked to plate tectonics. The divergence times traced by the study go back to the Cretaceous period, while the origin of Parreysiinae aligns with the breakup of Gondwana. Subsequent dispersal and vicariance events from the Cretaceous to the Miocene further shaped their present distribution.The researchers also recorded the aquatic leech Hemiclepsis myanmariana inhabiting the mantle cavity of the freshwater mussel Lamellidens generosus, highlighting a notable host-symbiont association in Manipur’s freshwater ecosystems.
Freshwater mussels are recognised as important ecosystem engineers because they filter water, cycle nutrients and help maintain the ecological health of freshwater habitats. The study noted that this unique biodiversity, which evolved over millions of years, is increasingly threatened by habitat fragmentation, pollution and overharvesting caused by human activities.
The researchers emphasised the need for strengthened conservation measures to protect freshwater mussels and their habitats in Manipur. They stated that proper documentation and conservation of these species are essential for maintaining the ecological balance of freshwater ecosystems in the region.
The findings have been published in two internationally recognised peer-reviewed journals: Biological Journal of the Linnean Society, published by Oxford University Press, United Kingdom, in 2026, and Ecologica Montenegrina, published by the Institute for Biodiversity and Ecology, Montenegro, in 2025.
The discovery of Indonaia manipurensis and Parreysia imphalensis adds to Manipur’s growing scientific importance as a region of rich freshwater biodiversity and provides valuable insights into the evolutionary history and biogeography of the Indo-Myanmar region.