Meet the blind, subterranean hexapods that have thrived for millions of years underground

Nature · Published 3 October 2026 Swipe more like this →

In short: Hidden beneath your feet in moist soil and leaf litter live the diplurans. These tiny, eyeless creatures are not insects, though they share a six-legged body plan. With their mysterious double-pronged tails and ancient lineage, these elusive soil-dwellers offer a silent, subterranean perspective on the health of our planet.

Diplurans belong to a group known as Entognatha, a classification that separates them from true insects. While they share the six-legged structure common to hexapods, their defining feature is their mouthparts, which are tucked away inside a small pouch within the head capsule. These creatures are remarkably widespread, inhabiting nearly every land mass on Earth, with the notable exception of Antarctica and various oceanic islands. Despite their global presence, they remain largely unseen due to their small size and strictly subterranean habits.

The order is defined by a pair of caudal appendages known as cerci, which project from the end of their bodies. These structures vary significantly between lineages: the Japygidae family sports aggressive, pincer-like appendages used for hunting prey, while the Campodeidae possess long, flexible filaments. Some species even exhibit autotomy, the ability to shed these cerci if threatened. Their bodies are typically unpigmented and lack eyes, relying on long, bead-like antennae to navigate their dark, damp environments. To maintain water balance, they utilize eversible vesicles on their abdomens to absorb moisture from the surrounding soil.

The life cycle of a dipluran is relatively brief, estimated at about one year, during which they may moult up to 30 times. Their reproductive strategy involves external fertilization, where males deposit stalked spermatophores that remain viable for roughly two days. The fossil record for these animals is sparse, but evidence from the Carboniferous period suggests that early ancestors, such as Testajapyx, possessed compound eyes and mouthparts more similar to those of insects. Today, their presence in the soil serves as a biological indicator, helping researchers measure the impact of human activity, such as farming-induced nutrient depletion, on the environment.

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