The earliest known fossil evidence of brooding behavior was presented in the March 13, 2014, edition of the journal Current Biology by a team of researchers led by University of Leicester geologist Professor David Siveter.
The newly discovered fossil is an ostracod. Ostracods are the ancestors of shrimp, lobsters, and crabs.
The 450 million-year-old fossils were found in mudstone rocks from New York State. The area at the time the ostracods lived is considered to have been mostly ocean.
The two to three millimeter long fossils were so well preserved that soft tissues and sex characteristics were retained.
The new species, Luprisca incuba, shows definite evidence of a routine incubation of eggs on or inside the female’s body and delivery of live young. The presence of newly delivered young near the females is indicative of brooding behavior post birth. The researchers consider the location of live young to be indicative of an undefined term of association between the female ostracod and their young before the young became independent. Ostracods are considered to have traveled the oceans and waters of Earth in large groups much like shrimp.
This is the oldest evidence of brooding behavior in an animal ever seen in the fossil record.