New Record of Freshwater Snail, Planorbella Trivolvis and Planorbella Pilsbryi in Maharashtra, India

Freshwater molluscs exhibit remarkable adaptability, thriving in diverse habitats and fluctuating climatic conditions. This study reports the first record of two exotic freshwater snail species, Planorbella trivolvis and Planorbella pilsbryi, in Maharashtra, India. Surveys conducted during 2016–2017 around the Godavari River in Gangapur, Nasik, revealed the presence of these species in ponds and slow-moving streams. Specimens were collected and identified through morphological and taxonomic analyses, with confirmation from the Zoological Survey of India. Planorbella trivolvis is characterized by a sinistral, discoidal shell with a diameter of 16–17 mm and is typically found attached to aquatic vegetation. The species thrives in lentic environments, tolerating pH levels of 7–8 and temperatures ranging from 20–28°C. Similarly, Planorbella pilsbryi exhibits strong ecological adaptability, surviving in muddy, polluted, and desiccated habitats. Its shell, also sinistral and discoidal, measures 15–17 mm in diameter. Both species are detritivorous, feeding on algae, decaying organic matter, and aquatic vegetation. This study highlights the invasive potential of these alien species, as they were found colonizing local ecosystems alongside native snails. The findings underscore the importance of monitoring molluscan diversity and understanding the ecological impacts of non-native species. As these snails can influence ecosystem dynamics and serve as indicators of environmental changes, further research is imperative to mitigate potential ecological disruptions caused by their introduction.