Workers are about 12.6–14.4 mm long.
Fine-art photographic collection
Polyrhachis medusa
A large East African ant armed with four separate petiole points and clothed so densely in hair that its sculptured armour is almost hidden.
About this species
Polyrhachis medusaForel, 1897
Information reviewed15 July 2026
Polyrhachis medusa is a robust East African spiny ant in the militaris group. Workers are black, heavily haired and protected by pronotal spines plus a petiole carrying paired spines and lateral teeth.
Taxonomy
Animalia · Arthropoda · Insecta · Hymenoptera · Formicidae · Polyrhachis
Accepted taxon. · checked 2026-07-15
Kenya, Tanzania and MozambiqueBroad range and selected reference localities — not a complete occurrence map.
Kenya, Tanzania and Mozambique
Warm woodland, coastal forest and shrub vegetation.
Workers forage above ground and on vegetation.
Sugary liquids and captured or scavenged arthropods.
Social colony with queens and workers.
What makes this species remarkable?
The petiole is transformed into a four-point defensive gateway: two dorsal spines and two strong lateral teeth surround the narrow joint leading to the abdomen.
Long dense hairs cover the body so completely that they conceal the fine reticulate sculpture underneath, giving the ant a matte, almost mammalian surface at macro scale.
At up to roughly fourteen millimetres, a worker is enormous for a formicine ant, yet the waist remains a single narrow articulated node carrying the full weight of the abdomen and its chemical-defence system.
More photographs
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