They Return Each Year to Fill Hands With Muck and Bones : Hancock Park: Fossil- hunters have dipped into the tar pit every summer since 1984. This time, they pulled out 552 specimens from the past.

The stirring sounds of “Raiders of the Lost Ark” filled the air as the fossil-hunters climbed one last time out of Pit 91, the nation’s only regularly excavated tar pit.

Every summer since 1984 volunteers have pulled Ice Age fossils from the bowels of Hancock Park. As chief excavator Eric Scott explained, it’s traditional to end each successful season by playing the music associated with Indiana Jones, the movie hero who makes the hot, tedious work of excavation look glamorous. A wrap party with pizza and beer is also planned.

The haul from this summer’s dig, which ended recently, was 552 specimens, including the fossilized bones of long-extinct saber-toothed cats, dire wolves and Ice Age condors, caught in the gooey asphalt that has been trapping animals for at least 40,000 years.

That was considerably fewer than last season’s total of 746 animal and plant specimens, Scott said. But it included an unusually large number of big bones.

On the last day, volunteer Gary Takeuchi, a geology student at Cal State Los Angeles, removed the season’s prize, a finely preserved dire wolf skull.

Its worn teeth indicated an animal that had managed to beat the ancient odds and survive until old age.

Originally excavated almost a century ago, the tar pits constitute one of the richest caches of Ice Age fossils in the world.

Preserved by the asphalt that ensnared them, 550 species of plants and animals have been recovered from more than 100 sites in the Hancock Park area.

The summer dig has been an annual event since it began in 1984 to coincide with the Olympics.

A $6,000 budget only allows for a nine-week dig. Summer is the preferred time, Scott explained, because the asphalt softens in the heat and more volunteers are available.

According to Christopher A. Shaw, who coordinates the summer dig for the George C. Page Museum of La Brea Discoveries, one reason Pit 91 was reopened in 1969 was to redress the bias of early paleontologists toward large remains, called macrofossils.

Of the more than 1 million specimens removed from the tar pits by early excavators, less than 1% were of plants or animals smaller than a rabbit, Shaw said.

Unlike the pits’ first excavators, today’s scientists treasure insect parts and other microfossils.

“We were taking out saber-toothed cat bones that were bigger than the bones in my body,” said Scott, 28.

As each fossil was painstakingly removed, some with dental picks, Scott made careful field notes, including a record of exactly how each specimen was positioned when found.

Saber-tooth bones were especially plentiful this year, Scott said. Evidence of four different individuals was uncovered.

Information about the 552 newly found specimens will end up in the Page Museum’s growing data base on Pit 91, Scott said.

Data on 48,000 specimens already taken from Pit 91 are now being computerized. The project will give scientists instant access to information that, in the past, was sometimes buried again in the museum’s files.