Construction workers in Oceanside have uncovered the fossilized skeleton of a prehistoric mammal believed to have lived between 40 and 45 million years ago, according to city officials. The discovery was made this month during excavation for an infrastructure project, with bones found about a dozen feet beneath the surface.
A paleontologist monitoring the site identified several limb bones, ribs, and other skeletal fragments during routine oversight of the construction work. Dr. Joseph El Adli, the principal paleontologist, quickly secured the location and spent a week with his team carefully extracting the remains from hardened layers of mudstone and sandstone. The fossils were wrapped in protective plaster casings before being transported to a laboratory for further analysis.
The remains date to the Eocene Epoch and were recovered from the Santiago Formation, a geological layer known to contain fossils from that ancient period. Scientists believe the bones belonged to a large, odd-toed hoofed mammal, potentially either a brontothere or an amynodon. Brontotheres, sometimes called "thunder beasts," were massive animals comparable in size to modern black rhinoceroses and featured distinctive horns. Amynodons, often referred to as "swamp rhinos," resembled hippopotamuses and lived in or near water.
Laboratory technicians will now remove the surrounding rock and stabilize the bones using specialized preservation materials. Once fully prepared, the fossils are expected to be placed in a museum collection for public viewing and scientific research.
The discovery was possible because Oceanside, following California environmental regulations, stations paleontological monitors at major construction sites. City officials have not disclosed the precise location of the find to prevent safety risks and protect the site from unauthorized interference.