India, Oct. 19 -- A six-year-old boy searching for fossils at a Nebraska park stumbled upon something far rarer than he had expected. Leo Youngdahl noticed an unusual imprint on a rock, prompting experts to take a closer look. The discovery has drawn attention because a similar fossil had not been recorded in the US state for more than 55 years.

Leo, who lives in Eagle, Nebraska, was attending a late-summer Rafting and Rocks event at Schramm Park State Recreation Area near Gretna when he came across a large rock. According to Outdoor Nebraska, a publication of the Nebraska Game and Parks Commission, he turned it over in the hope of finding his favourite fossils of crinoids, marine animals that often resemble plants.

Instead, he noticed ...