New Evolution Link

Press, Volume CVII, Issue 31551, 13 December 1967, Page 11

New Evolution Link

(By a staff writer of the

Science Monitor”)

The 30 - million-year-old skull of an ape-like creature has added another link to the chain of evolution of the human species. Dr Elwyn L, Simon*, a Yfde geologist and leader of a series of expeditions tn the remote eastern fringes of the Sahara in Egypt, recently announced the discovery of the skull by his associate, Dr Grant E. Meyer. It was found in February, 1966, in the Fayum Desert region about 60 miles southwest of Cairo.

On the last day of that winter’s expedition, Dr Meyer spotted it from 25 yards away, while walking along the base of a 300-foot bluff. “I didn’t know it was a whole skull when I found it,” he said. All he could see was the forehead at the surface of the ground. Nor could he immediately dig it out of the ground. Most fossils become hardened with mineral deposits over periods of millions of years. But at Fayum the sand and pebbles of the desert have been without water for so long that they never formed rock.

Pieces Glued

So the skull had slowly weakened and fragmented, but remained undisturbed—encas-

ed in the sandy sediment of a dried-up riverbed. To protect the find, the Yale palaeontologists poured many batches of thin glue into the skull and surrounding sand. Next they carefully dug out the artificially hardened chunk, wrapped it in wet paper, covered it with plaster, and shipped it home. It was in the laboratory that the discovery really unfolded. As Dr Simons and his colleagues carefully cleaned away the sediments, they found that most of the skull was still there—including the upper teeth. The teeth are allimportant. “It’s the teeth that prove it’s an ape,” he said. He also explained that comparison of the teeth with those of early apelike ancestors of man supported the theory that this extinct species belongs to the family trees of both humans and modern apes. Trees Indicated

Other fossils of flora and fauna found near the skull seem to be typical of the early Oligocene Age, about 30 to 35- million years ago. They show that the region was a tropical forest at the time. Petrified logs indicated the presence of trees as much as 100 feet tall. The skull seems to be that of a young creature about the size of a monkey. Dr Simons suggested that reptiles may have caught inexperienced offspring as they drank at the edge of the river.

He conservatively estimates that the skull is about 28 million years old. A layer of lava at the top of the cliff was examined to see how much of its radioactive potassium had decayed to argon. Comparing the amounts of these two chemical elements produced a date of about 25 to 26 million years.

The 300 feet of sand burying the skull beneath the lava could easily have been deposited by the river during the few million years just before the volcanic activity.

Earlier Find* Noted

Previously, the oldest known skulls in the ape and human families were about 14 to 18 million years old. There was a large gap in time between them and similar, but much older, fossils.

This made It difficult to find any correlation between these long-extinct species and the later ancestors of man. Dr Simons hopes the skull will be a great help in filling this gap. Very early in the evolution of primates a split developed among the various species. One branch eventually became the modern long-tailed monkeys (and their relatives). The other branch led to tailless apelike creatures. This second branch later split again, one branch leading to the apes and chimpanzees of today's world and the

other branch leading to the various human species. Near Split in Line

Dr Simons thinks his ape, Aegyptopithecus zeuxis (which means linking the Egyptian ape,) lived during the early stages of the secondary split in the evolution of the apes. He says, “This is at the crotch of the Y, and it’s thus sort of pedantic to say which branch it’s on.” It has some features similar to later species of apes, others similar to later species of human (though still apelike) ancestors, and still others related to earlier creatures. Palaeontologists believe it was at least another 14 million years after Aegyptopithecus that man’s ancestors began showing something of the adaptability of man. And the oldest tool-using hominids are only about 2 million years old. “A Howling Desert” Dr Simons describes the Fayum area as “a howling desert.” But he is optimistic about its future.

“I think other (skulls) can be found there,” he said. “I’d like to be there now. In fact, if it weren’t for the hostilities there, I would be.” East Africa is one of the few areas of the world with the peculiar dimate that preserves such old fossils. But even 99 per cent of that territory doesn’t have much left from the Oligocene Age. Most of it has disappeared through aeons of erosion and sedimentation.

The Fayum Desert is the best of only a very few known sources of fossils from this period. Dr Simons plans to return to continue his work there as soon as possible.

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