430-million year-old arthropod kept its kids on a leash
Derek Briggs, Derek Siveter, David Siveter, Mark Sutton, and David Legg

430-million-year-old arthropod kept its kids on a leash

Parents know how hard it can be to keep their kids from wandering off—and a new fossil find shows that animals have been looking for ways to deal with the same problem for hundreds of millions of years. Digging around in a rare volcanic deposit in Herefordshire, U.K., researchers found a 430-million-year-old fossil arthropod with 15 pairs of legs, antennalike stalks on its head, and no shortage of spines (pictured). And tethered to those spines are 10 capsules containing smaller arthropodswhich researchers say are likely its offspring. The leggy marine creature may have used these threads to keep its young ones close, making them less likely to get snapped up by predators. Some modern arthropods use similar strategies. Crayfish, for example, attach their embryos to themselves with stalks made of a cementlike secretion. The authors of this study—published today in the Proceedings of the National Academy of Sciences—also mention another possibility: Rather than being juveniles, the capsules could be parasites of another species, hitching a ride and stealing nutrients. But that’s a remote possibility at best. The threads are attached to the arthropods’ spines, and if parasites wanted to suck out nutrients, say the researchers, they’d stick themselves somewhere juicier.