The oldest evidence of parental care has been found in Ordovician mudstone in New York State. The species uncovered is new to science and has been named Luprisca incuba after the Roman goddess of childbirth. It is also the oldest evidence of ostracods, a type of crustacean, yet found.
Although 13,000 living species of ostcracod are known, along with more than 50,000 extinct versions, they keep a pretty low profile. After all, when a 3cm version gets named Gigantocypris you're a little easy to miss. Most live either as plankton on the open oceans or in the upper layer of the sea floor, while a few occupy forest soils in the remnants of Gondwanaland. They fossilize well however, and form the most common arthropod in the fossil record, so the discovery of 450 million year old examples was not a surprise.
The identification of both eggs and what appear to be recently hatched young, however, was much more unexpected. “This a very rare and exciting find from the fossil record. Only a handful of examples are known where eggs are fossilized and associated with the parent,” says Professor David Siveter of the University of Leicester, one of the authors announcing the find in Current Biology. ”This discovery tells us that these ancient tiny marine crustaceans took particular care of their brood in exactly the same way as their living relatives.”
Most remarkably of all we have not a single specimen but a host of them. The mother ostracods are 2-3mm long with even soft parts that seldom fossilize having been preserved. Some have eggs inside their bivalved shell, and some appear to be protecting hatched young.
Sieveter says L incuba occupied low oxygen conditions around the margin of the North American continent, and probably lived a lifestyle similar to their relatives today, scavenging and hunting on the sea floor. Previously the oldest confirmed ostracod fossils were 25 million years younger from the Silurian age.