A 'Missing Link' Fossil Adds 'Foliage' To The Early Human Ancestor Family Tree

April 27, 1999

East African paleo-anthropological sites have yielded 2.5-million-year-old fossils of a possible direct human ancestor. "These fossils are providing exciting new evidence about the long-sought evolutionary connection between species of early hominids, like Australopithecus, and the genus Homo," said National Science Foundation (NSF) Physical Anthropology Program Director Mark L. Weiss.

The cranial, leg, and arm bone fossils of this newly discovered species were unearthed in Ethiopia by a team of scientists led by NSF-supported anthropologist Tim White of the University of California-Berkeley and Berhane Asfaw of Ethiopia, and are publicized in the April 23 issue of Science magazine. Significantly, the femur is elongated-a million years before hominid fossil evidence shows forearm shortening-which, together with shortened forearm, creates the familiar modern human limb proportions.

Similar-age animal fossils discovered in the same area, the Middle Awash study area in the Afar desert, indicate that the meat and bone marrow of large mammals (antelopes and horses, specifically) were obtained with the world's earliest stone tool technology, according to a companion article in Science. White cautioned that "we cannot yet conclusively link the new species with the butchery or the more modern limb proportions."

Both sets of fossils were dated using the argon-argon radioisotope method as well as biochronology and paleomagnetism. The same research team had discovered the earliest-known hominid, the 4.4-million-year-old Ardipithecus, at the nearby Aramis site in 1992.

These fossil finds are significant for several reasons, according to the discoverers. "The hominid fossils may allow us to add a new member to the human evolutionary family tree," said Weiss, "and the evidence regarding the use of stone tools in food processing indicates an early reliance on meat in hominid diet. This adaptation would have allowed them to venture into new habitats and ultimately into new continents."

According to the discoverers, the new Ethiopian hominid fossils, named Australopithecus garhi, help fill a serious void in the east African record of human origins that spans a duration of between 2 and 3 million years ago. This void has made it impossible to settle scientifically the relationship between the 1.8-million-year-old Homo habilis and earlier ape-like Australopithecus africanus.

Increasingly, the focus on African early hominid fossil wealth has centered on Ethiopian sites in contrast to the last few decades' focus on better-known productive sites in Tanzania, Kenya and elsewhere. "With the publication of these new results, and with a record spanning five million years, Ethiopia's Middle Awash has become the world's most important single site for studying human origins and evolution," said White.

The research in the Middle Awash area is supported mainly by the National Science Foundation. Additional support comes from the Institute of Geophysics and Planetary Physics of the University of California's Los Alamos National Laboratory and several other institutions mentioned in the published Science articles. The international research team includes archaeologists, geologists and paleontologists from diverse institutions in 13 countries.
-end-


National Science Foundation

Related Fossils Articles from Brightsurf:

First exhaustive review of fossils recovered from Iberian archaeological sites
The Iberian Peninsula has one of the richest paleontological records in Western Europe.

Fossils reveal mammals mingled in age of dinosaurs
A cluster of ancient mammal fossils discovered in western Montana reveal that mammals were social earlier than previously believed, a new study finds.

Oldest monkey fossils outside of Africa found
Three fossils found in a lignite mine in southeastern Yunan Province, China, are about 6.4 million years old, indicate monkeys existed in Asia at the same time as apes, and are probably the ancestors of some of the modern monkeys in the area, according to an international team of researchers.

Scientists prove bird ovary tissue can be preserved in fossils
A research team led by Dr. Alida Bailleul from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences has proved that remnants of bird ovaries can be preserved in the fossil record.

Biosignatures may reveal a wealth of new data locked inside old fossils
Step aside, skeletons -- a new world of biochemical ''signatures'' found in all kinds of ancient fossils is revealing itself to paleontologists, providing a new avenue for insights into major evolutionary questions.

Fish fossils become buried treasure
Rare metals crucial to green industries turn out to have a surprising origin.

New Argentine fossils uncover history of celebrated conifer group
Newly unearthed, surprisingly well-preserved conifer fossils from Patagonia, Argentina, show that an endangered and celebrated group of tropical West Pacific trees has roots in the ancient supercontinent that once comprised Australia, Antarctica and South America, according to an international team of researchers.

Ancestor of all animals identified in Australian fossils
A team led by UC Riverside geologists has discovered the first ancestor on the family tree that contains most animals today, including humans.

Metabolic fossils from the origin of life
Since the origin of life, metabolic networks provide cells with nutrition and energy.

Fossils of the future to mostly consist of humans, domestic animals
In a co-authored paper published online in the journal Anthropocene, University of Illinois at Chicago paleontologist Roy Plotnick argues that the fossil record of mammals will provide a clear signal of the Anthropocene era.

Read More: Fossils News and Fossils Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.