"People always assume that biodiversity starts in shallow waters and moves to the deep sea, but these findings are evidence that the deep sea may be a neglected source of biodiversity,"said lead study author Ben Thuy, an invertebrate paleontologist at the National Museum of Natural History of Luxembourg.
A landslide in Glasenbach Gorge near the city of Salzburg in Austria exposed the fossils. Then, over the course of a decade, Moosleitner collected the fossils, alerting Thuy and his colleagues of the treasure trove there.
"The slopes of the gorge we got fossils from were quite steep, which made work a bit difficult, but it was also quite fun," Thuy told Live Science. "We dug up the rock, put it in a sieve, and washed [the rocks] in the brook downslope to get fossils. It was a bit like panning for gold."
The scientists deduced that these fossils came from deep-sea deposits from the absence of fossils of light-dependent organisms, as well as from physical similarities between the rock surrounding the fossils with modern deep-sea rock. The 2,500 or so fossils included the oldest-known members of a number of groups of deep-sea creatures alive today.