SAN JUAN CAPISTRANO : Fossil Find May Be a Rare Whale

If their early predictions and hopes prove correct, paleontologists from the San Diego Natural History Museum may have found the fossil remains of a 5-million-year-old whale at a local construction site.

According to museum spokesman Tom Demere, early indications are that the whale remains--now largely encased in a matrix of hard mudstone--are those of a beaked whale. The species is a variety of toothed whale distinguished by beak-like snouts.

Demere said museum experts are “90% certain” that the whale uncovered in San Juan Capistrano is a beaked whale.

Brad Riney, a museum paleontologist, found the fossils June 29 while working at a construction site for a new Lusk Co. housing and golf course development called Lomas San Juan. Under state law, developers of large sites are required to hire paleontologists to search for significant fossils during excavation--a process Riney describes as “sitting down and watching the equivalent of 100,000 years of erosion happen in an hour.”

He said he was walking behind a large earth mover working a hillside when the machine cracked open several large rocks. “I could tell right away from the cross sections that there was fossil material inside,” Riney said.

Riney said he immediately suspected the fossil material came from a toothed whale.

The surrounding layers of earth deposits led Riney and Demere to place the whale’s age at about 5 million years, or hailing from the geologic era called “Early Pliocene.”

At that time, he said, much of what is now the South County coast was part of a deep-water abyssal plain. When the whale died, experts speculate that its body sank to the sea floor and was covered by gray mud. Over the millennia, the sea floor rose until the whale’s fossilized remains wound up 200 feet above sea level in the San Juan Capistrano hillside, he said.

Riney believes he uncovered about one-third of the whale’s body, from the skull to the rib cage.

His discovery marks only the sixth time that the remains of a beaked whale have been uncovered on North America’s western coast, according to Lawrence Barnes, curator of vertebrate paleontology at the Los Angeles County Museum of Natural History.

These earlier finds date as far back as 20 million years, Barnes said.

Since modern beaked whales normally have ranges limited to narrow bands of latitude, Demere believes that this ancient specimen may prove to be an undiscovered species. Barnes concurred, calling the excavation “extraordinary.”

The skull portion of the fossil measures about 30 inches from the tip of the snout to the back. Consequently, paleontologists believe the whale once spanned 15 feet in length and weighed about 2,200 pounds. The creature probably survived on squid and fish.

If Demere and Riney are correct, the find will help fill a gaping hole in the fossil record and may provide a “bridge” between older specimens and modern whales, experts said. Although other whale types are regularly found--Riney has uncovered remains of two baleen whales at the same site--beaked whales have remained elusive.

Riney believes the fossil may be more fodder in the debate over whether evolution occurs gradually or in a series of punctuated events.