Featured Research

from universities, journals, and other organizations

Chimp-sized Hominid Walked Upright On Two Legs Six Million Years Ago

Date:
September 3, 2004
Source:
Penn State
Summary:
Recent fossil evidence suggests that a hominid, the size of a chimp, walked upright on two legs in Kenya's Tugen Hills, over 6 million years ago --- about 3 million years earlier than "Lucy," the most famous early biped in our lineage.

Left: Reconstruction of the fossil bone from CT slices. The vertical line indicates the plane of the view shown on the right.
Credit: Image courtesy of Penn State

University Park, Pa. -- Recent fossil evidence suggests that a hominid, the size of a chimp, walked upright on two legs in Kenya's Tugen Hills, over 6 million years ago --- about 3 million years earlier than "Lucy," the most famous early biped in our lineage.

Dr. Robert Eckhardt, professor of developmental genetics and evolutionary morphology, Laboratory of Comparative Morphology and Mechanics (LCMM), Department of Kinesiology at Penn State, led the U.S. research team responsible for analysis of the CT scans of the internal structure of the fossil bone. Eckhardt says, "We have solid evidence of the earliest upright posture and bipedalism securely dated to six million years."

The evidence is detailed in the current (Sept. 3) issue of Science in a report, "External and Internal Morphology of the BAR 1002'00 Orrorin tugenensis Femur." Eckhardt's co-authors are Karl Galik, Orthopedic Biomechanics Laboratory, Allegheny General Hospital, Pittsburgh, Pa.; Brigitte Senut, Department of Earth History, National Museum of Natural History, Paris, France; Martin Pickford, who holds the chair of paleoanthropology and prehistory at the College of France and at the Department of Earth History of the National Museum of Natural History, Paris, France; Dominique Gommery, National Center for Scientific Research, Paris, France; Jacques Treil, Radiology Department, Pasteur Clinic, Toulouse, France; and Adam Kuperavage, a graduate student in Penn State's LCMM.

The fossil the team studied is part of a left thighbone unearthed nearly four years ago by Senut and Pickford at their dig in the Kenyan Lukeino Formation. The fragment includes the intact head of the left thighbone -- the ball that is inserted into the hip socket joint -- plus the bony neck that connects the ball to the thighbone shaft as well as part of the thighbone shaft.

Measurements, chiefly carried out by Dr. Galik, show that the fossil bone is about the same size as a chimpanzee's. However, CT scans of the interior of the bone reveal that the neck connecting the ball to the shaft is thinner on top than it is on the bottom, a sign the researchers say that the individual from which it came walked on two legs.

Eckhardt says, "In present day chimps and gorillas, the thicknesses in the upper and lower parts of that bone are approximately equal. In modern humans, the bone on top is thinner than on the bottom by a ratio of one to four or more. The ratio in this fossil is one to three."

The ratio in the fossil is evidence for transition to an upright posture and habitual bipedal gait the researchers argue. In addition, Eckhardt notes, because walking upright is the essential mark of a hominid, the ratio is functional evidence that the bones fossilized at Lukeino were from hominids.

The researchers write, "In known features, external and internal, BR1002'00 exhibits a total morphological pattern distinct from African apes, diagnostic of bipedal locomotion and appropriate for a population standing at the dawn of the human lineage."

The imaging research was supported, in part, by grants from the American Philosophical Society and from Sigma Xi.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Cite This Page:

Penn State. "Chimp-sized Hominid Walked Upright On Two Legs Six Million Years Ago." ScienceDaily. ScienceDaily, 3 September 2004. <www.sciencedaily.com/releases/2004/09/040903085349.htm>.
Penn State. (2004, September 3). Chimp-sized Hominid Walked Upright On Two Legs Six Million Years Ago. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2004/09/040903085349.htm
Penn State. "Chimp-sized Hominid Walked Upright On Two Legs Six Million Years Ago." ScienceDaily. www.sciencedaily.com/releases/2004/09/040903085349.htm (accessed September 17, 2014).

Share This



More Fossils & Ruins News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) — Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Museum Traces Fragments of Star-Spangled Banner

Museum Traces Fragments of Star-Spangled Banner

AP (Sep. 12, 2014) — As the Star-Spangled Banner celebrates its bicentennial, Smithsonian curators are still uncovering fragments of the original flag that inspired Francis Scott Key's poem. (Sept. 12) Video provided by AP
Powered by NewsLook.com
Spinosaurus Could Be First Semi-Aquatic Dinosaur

Spinosaurus Could Be First Semi-Aquatic Dinosaur

Newsy (Sep. 11, 2014) — New research has shown that the Spinosaurus, the largest carnivorous dinosaur, might have been just as well suited for life in the water as on land. Video provided by Newsy
Powered by NewsLook.com
Meet Spinosaurus, the First-Known Water Dinosaur

Meet Spinosaurus, the First-Known Water Dinosaur

AFP (Sep. 11, 2014) — Spinosaurus aegyptiacus was adapted for both land and water, and an exhibit featuring a life-sized model, based on new fossils unearthed in eastern Morocco, opens at the National Geographic Museum in Washington on Friday. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins