Water Project Dig Unearths an Ancient 'Beast'

Crews digging for a water project in Oceanside, Calif., just hit a very big, very old surprise. About 12 feet down, workers uncovered limb bones, ribs, and other fragments from a large hoofed mammal that roamed the region roughly 40 million years ago, scientists say. Paleontologist Joseph El Adli thinks the animal is either a brontothere—a deep-chested horse relative nicknamed a "thunder beast"—or an amynodont, sometimes called a "swamp rhino," a semi-aquatic, rhino relative with big canine teeth instead of a horn, per the Los Angeles Times.

Of the two plant-eaters, the brontothere was more common, leading El Adli to suspect that is what he's found, reports the San Diego Union-Tribune. A city statement notes preserved blocks of stone may contain a skull, which "could settle the question." The largest bone found so far, a suspected femur, is almost 3 feet long. The fossils, pulled from the fossil-rich Santiago Formation during a 10-day excavation, were cased in plaster, then moved to a Carlsbad lab where they'll be studied over the next several weeks. The city says they'll eventually go to a museum for public display. The hunt for a skull and other bones continues.