Road Builders Travel Back in Time : Highway Construction Turns Up Fossils of an Ancient Camel Ancestor

Caltrans workers and paleontologists announced Monday that they have uncovered a nearly complete skeleton of a 47-million-year-old ancestor of the camel, a species never identified before.

The fossil find, part of a rich cache of ancient bones discovered about 11 miles northeast of downtown San Diego where workers are building a highway, will let scientists gain new insights about the Earth’s earliest mammals.

“We are talking about way back to the dawn of the evolution of mammals,” said Thomas Demere, head of the paleontology department at the San Diego Natural History Museum.

The paleontologists found remains of several mammals that fed on plants in the area during the mid-Eocene age. The discoveries include about half a dozen partial skeletons of the protoreodont, a distant cousin to the camel, and the rhinoceros-like brontothere.

The fossil finds have been made since October when construction began on a highway extension--a 10-mile long, four-lane connector between Interstate 15 and California 67, Demere said. Many were displayed Monday for journalists at the excavation site.

The highway addition, meant to reduce congestion on the interstate and to link a four-freeway network has also provided entree into an ancient period about which scientists knew little. This species of dog-sized protoreodont had not previoiusly been identified, Demere said.

“With these finds, we have gradually been able to fill in the picture,” said Demere as he displayed stones with animal skulls and bones embedded. Next to the display was an artist’s rendering of how the area appeared during the Eocene epoch. “If it hadn’t been for the construction, we wouldn’t have found these,” he said.

Caltrans has arranged for the museum to do the paleontological supervision during road construction for about a decade, since a state environmental act mandated that private and public developers in fossil-rich areas work to avoid destroying remains, said Chris White, environmental branch chief for Caltrans.

The remains were found in three sites in the construction area, all in fine-grain sedimentary rock about 30 feet below the surface, White said.

The museum has uncovered significant finds during construction work on California 78 in northern San Diego County and on building sites in Chula Vista south of San Diego. The discoveries have made San Diego County the “richest assembly of fossils west of the of the Rocky Mountains,” Demere said.