Neanderthal tot enters human-origins debate.

Around 60,000 years ago, one or more Neandertals buried a dead 10-month-old infant in a cave in northern Israel. Before filling the grave with dirt, someone placed the jawbone of a red deer against the baby's hip in a gesture that apparently held symbolic meaning.

That, at least, is the scenario presented by scientists who unearthed the infant's remains in 1992 at the Amud cave near the Sea of Galilee. Their analysis of the fossil, set to appear later this yar in the JOURNAL OF HUMAN EVOLUTION, supports the view that Neandertals inhabited the Midle East along with Homo sapiens. It also suggests that Neadertals possessed enough unique skeletal traits to exclude them from playing any role in the evolution of modern humans.

"The exciting thing is that we can identify a Neandertal infant based on anatomical structures outside the midfacial region," asserts Yoel Rak, an anatomist and paleontologist at Tel-Aviv University in Israel. Neandertal midfacial bones portray sloping foreheads, swept back cheeks, and projecting jaws.

Only the lower jaw, skull base, and several cranial bones remain in good shape on the Israeli specimen, report Rak and his co-workers, William H. Kimbel, an anthropologist at the Institute of Human Origins in Berkeley, Calif, and Erella Hovers, an archaeologist at Hebrew University in Jerusalem. The vertebral column and ribs also survived the millennia, as did incomplete pieces of the pelvis and other lower-body bones.

And Amud infant displays three features unique to Neandertals, Rak argues: a chinless lower jaw; an oval-shaped hole in the base of the skull, called the foramen magnum, through which the spinal cord passed; and a bony lip at the back of the lower jaw, on the inner surface, where an important chewing muscle attached.

From below, the Amud jaw shows a "squarish" profile, indicating the lack of a chin, Rak contends. A similar profile characterizes older juvenile Neandertal jaws found in Eastern Europe and the Middle East, he says. In contrast, fossils of anatomically modern children found at Israeli sites fron the same period contain triangular lower jaws, signifying the presence of a chin, he says.

The oval foramen magnum of the Amud specimen also departs from the rounded shape of this feature in living humans and most other primates, Rak adds. Four other partial skull bases of Neandertal children found elsewhere show an oval-shaped foramen magnum, he maintains.

It remains unclear whether this trait reflects any major differences in the workings of the Neandertal spinal cord and central nervous system.

The third clue to the fossil baby's species comes from bony protrusions for a chewing muscle know as the medial pterygoid. These bumps along the jaw's inner surface get larger toward the back of the mouth. Thus, the muscle thickened as it moved up the lower jaw, Rak holds.

The muscle markings end at a bondy lip, which served as an anchor for the medial pterygoid, the Israeli researcher notes. The same feature occurs on other Neandertal fossils but not on fossil or modern H. sapiens, he asserts.

The function of a think medial pterygoid muscle at the back of the mouth eludes Rak. In fact, it contradicts his prior theory that Neandertals chewed their food most vigorously with their front teeth.

Still, Neadertals apparently passed these three traits on genetically, since the features appear even in infant, Rak argues. Only a species distinct from H. sapiens could display these and other unique structures, he adds.

Controversy over Neandertals in the Middle East continues, however (SN: 6/8/91,p.360). Some researchers, such as Fred H. Smith of Northern Illinois University in DeKalb, welcome the new find, yet still class Neandertals and early modern humans in that region as closely related subspecies. Other place the two groups in a single population of "archaic" H. sapiens.