Taxonomy of millipede Diplopoda fauna in the sacred groves of northern Kerala

Abstract

Millipedes (Class: Diplopoda) are crucial macroarthropods of the soil ecosystem, contributing significantly to decomposition and nutrient cycling. Despite their ecological importance and wide distribution—excluding only Antarctica—they remain one of the least studied groups in Indian biodiversity research. This study, focused on the sacred groves of north Kerala, represents a pioneering effort in documenting the diversity, biogeography, and seasonal activity of millipedes in the region. Through extensive field surveys conducted over three years and integrative taxonomic approaches, the study elevated the known species count in Kerala from 57 to 70, including the discovery of nine species new to science, along with several new state and regional distributional records. The study also reported, for the first time in India, a mermithid nematode parasitizing a millipede, revealing unexplored aspects of diplopod parasitology. Observations on seasonality showed peak millipede activity from June to November, corresponding to the monsoon and post-monsoon periods. The documentation of widely distributed as well as endemic species reinforces the biogeographic uniqueness of the Western Ghats, particularly Kerala’s sacred groves and high-altitude regions, as critical refugia for rare and endemic taxa. This study underscores the importance of faunal documentation as the foundation of biological conservation, particularly for poorly studied and culturally sensitive ecosystems. However, challenges such as seasonal limitations, insufficient ecological data, and cultural restrictions on access to sacred groves was faced during field surveys. These barriers, coupled with increasing anthropogenic pressures, highlight the urgent need to integrate millipede taxonomy with conservation planning. Overall, the findings provide a significant baseline for future research in systematics, ecology, behaviour, and conservation of millipedes in India. The study emphasizes the necessity of habitat preservation, restoration of lost vegetation, and policy-level recognition of soil invertebrates as vital components of biodiversity. By illuminating the overlooked diversity of millipedes, this study reinforces the Western Ghats’ status as a global biodiversity hotspot that demands sustained scientific and conservation attention.