Horseshoe crabs have been crawling on our planet for nearly half a billion years, yet for all the brains we evolved in our measly half-million-year existence, we never did figure out what they actually are. Now a genetic study published this weekend in the journal of Systematic Biology finds evidence for the theory first postulated in the year 1881: the horseshoe crab is not a crab after all. It is a sister group to Ricinulei, the hooded tick spider.
Office of Strategic Communication