Tags: Arachnid.
Cyclocosmia or trapdoor spider is a genus of spiders in the Ctenizidae family.The abdomen of spiders in this genus is abruptly truncated and ends in a hardened disc which is strengthened by a system of ribs and grooves. They use this to clog the entrance of their 7 to 15 cm deep vertical burrows when threatened a phenomenon called phragmosis. Strong spines are located around the edge of the disc.
