Scientists have identified a new species of spiny ant thriving in the fragmented forests on the outskirts of Guwahati. This finding shows the ecological value of urban green spaces.

The new species, Polyrhachis garbhangaensis, commonly known as the "Assamese Spiny Ant", was found in Garbhanga Reserve Forest. This 117 sq km green corridor borders the city and is contiguous with Rani Reserve Forest.

This discovery counters narratives of widespread insect decline in the region. It also shows that even pressured forest patches continue to support undocumented biodiversity and complex ecological interactions.

The research was led by Ankita Sharma, a PhD scholar at the National Institute of Advanced Studies (NIAS), Bengaluru. The team included Paul Antony Mangaly, Suraj Kumar Singha Deo, Sangavi D, and senior researcher Prof. Anindya Sinha.

Field sampling using pitfall traps was conducted in August 2023. This was part of a broader study on the impacts of urbanisation on ant and spider assemblages in South Guwahati.

A preprint was posted on bioRxiv on August 19-20, 2025. The formal description was later published in the international journal Asian Myrmecology (Volume 19: 019001, pp. 1-9) on January 30, 2026.

The ant measures about 5.6 mm. It belongs to the rare Polyrhachis mucronata group and is only the third species recorded from India. It has a glossy black body, a vivid yellowish-orange abdomen (bright in life and turning yellow-brown when preserved), and distinctive curved spines on the petiole and propodeum. These features likely serve as defence against predators.

Researchers also observed an ant-mimicking spider at the same site, suggesting ongoing predator-prey interactions.

"This finding… highlights the importance of urban and fragmented forest areas in sustaining tropical ant biodiversity." The Study noted.

The authors note that Garbhanga's mix of habitats supports specialised species despite surrounding development.

Assam already records 217 ant species across 58 genera, with Polyrhachis showing notable diversity. Earlier surveys had indicated that human activities can reduce ant richness outside core forests. However, this discovery shows that protecting even small urban-adjacent patches can help safeguard vital ecosystem engineers, predators, soil aerators, and seed dispersers essential to tropical ecosystems.

While global insect declines remain a serious concern, Assam's ants appear resilient in these green areas.

Officials said that conserving fragmented forests like Garbhanga is essential for preserving the state's biodiversity before further urban pressure limits such discoveries.