New freshwater crab genus identified in Yercaud

Scientists have identified a new genus and species of freshwater crab from the Shevaroy Hills in Yercaud, Salem district, adding to India’s growing record of freshwater crustacean diversity.

The newly described genus, patithelphusaand his kind, Patithelhusa yercaudensiswere discovered during a zoological survey by researchers from the Zoological Survey of India (ZSI), Kolkata and Pukyong National University, South Korea. The study was led by Santanu Mitra and Shibananda Rath of ZSI, along with researchers Hyun-Woo Kim and Shantanu Kundu.

The genus is named in honor of Sameer Kumar Pati, a noted Indian taxonomist who made significant contributions to the study of freshwater crabs.

The specimens were collected from a muddy microhabitat next to a rocky stream at Manjakuttai in the Shevaroy Hills, located more than 1,400 meters above sea level. The crabs were preserved and examined in the Crustacea division of the ZSI, where detailed morphological studies were carried out, followed by molecular analysis using mitochondrial DNA sequences.

This is evident from the research published in the international zoological journal ZooKeys Patithelhusa yercaudensis is genetically and morphologically distinct from its best known relatives. It shows a genetic abnormality of 9.66% Travancoriana schirneraea species found in southern India. Morphologically, it can be identified by its broader carapace, distinct triangular lobes and unique features of the male reproductive structures, which differ from other genera such as Baratha, Take a bathAnd Vela.

The study suggests that the crab’s evolution may have been shaped by the topographical isolation of the Shevaroy Hills, separated from nearby areas by deep valleys and the Cauvery River system. These natural barriers likely limited gene flow, allowing crab populations to evolve independently over time. Such high altitude habitats in the Eastern Ghats can serve as a refuge for endemic species that have adapted to specialized environments.

The discovery highlights the ecological significance of the Eastern Ghats, a region relatively less studied than the Western Ghats. The researchers note that the diversity of freshwater crabs in the Indian subcontinent is still being discovered, with many species only known from limited localities.

With this discovery, the number of recorded freshwater crab species from India rises to 112, belonging to 31 genera under the family Gecarcinucidae, the study notes. India accounts for almost 10% of the world’s known freshwater crab species, many of which are restricted to small, localized habitats.

The authors say continued research and documentation are needed to better understand the diversity of freshwater crabs in peninsular India. They add that protecting mountain stream ecosystems is crucial as these habitats face increasing pressure from tourism and land use changes in regions such as Yercaud.