Palaeocampa lived among freshwater fish and sharks like xenacanths, small freshwater arthropods like the bizarre horseshoe crab Alanops, in lakes and rivers among the thriving coal forests of the Carboniferous.

There is no other lobopodian quite like it.

In fact, Palaeocampa's spines were not its only defence - the papilale that lined the animals dorsum (the upper surface) are sclerotized, with small pores at their centre which housed small setae.

These armoured papillae gave its back a rough, pebbly appearance.

It is most similar to Hadranax from the Sirius Passet. They both have stubby, clawless limbs, yet longer than those of velvet worms - they both have elongate frontal appendages, bodies lined with papillae, and a thickened dorsal cuticle.

Our phylogenetic analysis places Palaeocampa among the Aysheaiids (the classic Burgess Shale animal Aysheaia being its namesake), a group of poorly known lobopodians known from the Cambrian and Ordovician. Palaeocampa is the only known aysheaiid to possess a sclerite armature.

They are septated internally, and serrated externally - even without the poison, these would have been painful to touch. Unlike the urticating hairs of some modern arthropods and plants, these were firmly attached to the body, so their exact function is a mystery.

The spines themselves are incredible, and their preservation is immaculate - these spines are unique in the animal kingdom, even among other lobopodians. They emerge from bundled, modified "basement papillae", and only tape slightly at the top before opening outwards again.

Our FTIR results support the idea that this fluid, pushed out of the spines upon burial, was likely a natural chemical defence - either poison, or some foul-tasting chemical irritant.

Poisonous lobopodians have been speculated on before, but this is the first solid proof.