A spider that lives in a flooded stone tube: a new species was hiding on two tiny Mauritian islets

Dr Max Tercel had finished surveying everything else. All that remained on Ilot Vacoas — a one-hectare islet off southeast Mauritius — was a stretch of coastal rock where nobody expected anything remarkable. Headtorch on, he found legs extending from a burrow: a trapdoor spider, living not in forest soil but in ancient tubes in coralline rock that flood at high tide. Formally identified by the Durrell Wildlife Conservation Trust on 27 October and described in the journal Arachnology, Idioctis marevallum — 'sea wall' — seals its tube with a trapdoor of silk, sand and algae; when researchers poured seawater over nests, the spiders pulled their doors tighter and stayed dry inside. The wider study added 14 species to Mauritius's spider list, taking it from 37 to 51.

SDG 15 · Life on land