The earliest shark nursery containing fossils of both young sharks and eggs has been found at the site of a nuclear power plant in northeastern Illinois.
The nursery, once located at what is now Mazon Creek at the Braidwood Nuclear Generating Station site, dates to 310 million years ago, according to a paper published in the Journal of Vertebrate Paleontology. It used to be teeming with a long-snouted shark called Bandringa, which was one of the earliest close relatives of all modern sharks.
"At least a dozen juvenile Bandringa shark fossils -- and probably more -- have been recovered from the site," University of Michigan paleontologist Lauren Sallan, who co-authored the paper with Michael Coates, told Discovery News.
Some of the fossils are in a remarkable state of preservation.
"We even have soft body tissue from the juvenile sharks," Sallan said, adding that the tissue retains pigment that, in the future, could reveal the precise coloration of the sharks. DNA could probably not be extracted from it, though.