The Edmond Sun

Features

October 17, 2013

Ancient skulls suggests one lineage for early human ancestors

SAN FRANCISCO — A "time capsule" from 1.8 million years ago, located in Dmanisi, Georgia, shows variations among five human skulls from that period that suggest long-debated distinctions about early human development may be overblown.

The differences between the skulls were no more than that seen in modern humans, according to a report Thursday in the journal Science. The findings suggest there may have been only one species of early human in a key period of time when they first began to migrate out of Africa, said David Lordkipanidze, an anthropologist at the Georgian National Museum in Tbilisi and the report's author.

The analysis drew immediate criticism from scientists who said other members of the hominid family — Homo erectus, Homo habilis, and Homo rudolfensis — were identified using more than just their skulls. Lordkipanidze said the Dmanisi artifacts offer the earliest known representation outside of Africa of human development after the migration.

"Dmanisi has a uniqueness: it's a real snapshot in time, a time capsule from 1.8 million years ago," he said on a phone call with reporters.

The site, which sits below the ruins of the medieval town of Dmanisi, in the Mashavera River Valley, was discovered in 1983, when archaeologists studying the medieval town noticed bones of species they knew were extinct. In 1984, ancient stone tools were found there.

One of the five skulls found at the site recently had a small braincase, a long face, and large teeth, features never before seen together, according to the paper in Science. It was discovered with four other crania from the same place and time.

The skull has "a strange combination of features we didn't see before in early Homo," said Marcia S. Ponce de Leoacuten, a report co-author, of the Anthropological Institute and Museum in Zurich, in a call with reporters. Its location with other contemporary skulls allows the researchers to compare them to each other, she said.

The jaw of the skull was found first, in 2000, and the rest of the skull was found in 2005. Its braincase is "unexpectedly small," said Ponce de Leon, measuring only 33.3 cubic inches (546 cubic centimeters). Modern humans have an average brain volume of about 76 cubic inches (1,250 cubic centimeters).

Given that the population of individuals showed no greater range of variation than that of 5 humans or bonobos, the researchers proposed that early Homo individuals may not represent three species, but one.

"The variation within the samples from Africa is no more than our variation within homo erectus," said Christoph Zollikofer from the Anthropological Institute and Museum in Zurich, Switzerland, a co-author on the Science report. "We're pretty sure that the variation is within a single species, and we're calling it homo erectus."

Other anthropologists urge caution, saying the differences in cranial shapes may not reflect changes in other bones.

Bernard Wood, a professor of human origins at Georgetown University in Washington, D.C., said he was convinced all the skulls from the site belonged to the same group. However, he didn't agree with the group's larger generalization.

"They look at this overall cranial shape and say, 'If you look at Homo habilis and erectus, there isn't much more difference," Wood said by telephone. "You can't infer the latter from the former."

The reason why Homo habilis and Homo erectus are viewed as distinct isn't just the cranial shape, Wood said. Changes in the wrists and ankles, as well as in leg bones, took place at that time. Merging the classes doesn't make sense even if they share cranial shapes, he said.

The finding likely won't change expert's views on species diversity, where two groups are heavily entrenched said William Harcourt-Smith, an assistant professor at Lehman College and a research associate in the American Museum of Natural History's Division of Paleontology.

Some, nicknamed "splitters," see the tree of evolution as having many species. Others, called "lumpers," see wider species categories and fewer limbs on the tree.

"To be honest it just adds some important fuel to the debate," Harcourt-Smith wrote in an email. "The lumpers, of course, will love this new paper, but I can see splitters saying that there is too much variation in both the African early Homo and Dmanisi sample for them to all be Homo erectus."

 

1
Text Only
Features
  • Cats outsmart the researchers

    I knew a lot had been written about dogs, and I assumed there must be at least a handful of studies on cats. But after weeks of scouring the scientific world for someone - anyone - who studied how cats think, all I was left with was this statement, laughed over the phone to me by one of the world's top animal cognition experts, a Hungarian scientist named Ádám Miklósi.

    April 23, 2014

  • clock edit.jpg Antique clock collection on display at Edmond Library

    In a world that’s often hurried and brief, the Sooner Time Collectors have nothing but time. Oklahoma chapter members of the National Association of Watch and Clock Collectors have provided antique pieces from personal collections to display at the Edmond Library until the end of April.
    Since the 1950s, Sooner Time Collectors have gathered to learn about the inner workings of clocks and to admire one-of-a-kind finds. Of interest to the community is their involvement with repairs for the Cowboy Hall of Fame clock and the UCO tower. They now have 35 members who meet monthly as a chapter of the 16,000-member NAWCC community across America and the world.

    April 23, 2014 1 Photo

  • Be on the lookout for termites

    Warming temperatures and spring rainfall means swarming conditions for the homeowners’ nemesis in Oklahoma — the termite.
    Termites are Mother Nature’s way of recycling dead wood, as well as aerating the soil and increasing its fertility and water percolation. They are an important food source for other insects, spiders, reptiles, amphibians and birds within the food web, and they are essential for the wellbeing of the environment.

    April 23, 2014

  • McCain 1 House Republicans are more active on Twitter than Democrats

    Your representative in the House is almost certainly on Twitter. Your senator definitely is. But how are they using the social network? Are Democrats more active than Republicans, or vice versa? Who has the most followers on the Hill?

    April 22, 2014 1 Photo

  • Do your genes make you procrastinate?

    Procrastinators, in my experience, like nothing better than explaining away their procrastination: General busyness, fear of failure, and simple laziness are just a handful of the excuses and theories often tossed around. Now researchers from the University of Colorado Boulder have added another option to the list: genetics.

    April 22, 2014

  • VIDEO: Moose charges snowmobile, flees after warning shot

    While snowmobiling in New England, Bob and Janis Powell of Maine were charged by a moose and caught the entire attack on camera.

    April 22, 2014

  • 6th annual run event in Guthrie to benefit Free to Live

    The sixth annual “The See Spot Run” will take place at 9 a.m. May 10 in downtown Guthrie. This 5K, 10K and 1-mile run/walk event benefits Free to Live, a nonprofit animal sanctuary located Logan County. In the past five years of this event “The See Spot Run” has welcomed more than 3,000 runners and raised $30,000 for the Free to Live Animal Sanctuary.
    “The See Spot Run” will offer all participants the opportunity to compete in either the 5K or 10K event in addition to a 1-mile “Fun Run.” Walkers and runners (both two- and four-legged) are welcome and can register directly at www.theseespotrun.com. Visit www.freetoliveok.com. Donations also can be sent to “The See Spot Run,” P.O. Box 292, Guthrie, 73044.
     

    April 21, 2014

  • Touch-A-Truck event draws families to UCO

    Edmond Electric and Edmond Vehicle Maintenance are co-hosting the Edmond Touch-A-Truck from 9 a.m. to 1 p.m. May 17 in the UCO parking lot off Second Street. Touch-A-Truck is a fundraising event that provides children of all ages with the opportunity to experience life-size vehicles and interact with community support leaders like police officers, firemen, construction workers and many more. Families will have the opportunity for a hands-on exploration of many vehicles such as Edmond’s own fire trucks and police cars, an Edmond Electric bucket truck and even a solid waste truck.
    Admission for the Touch-A-Truck event is a suggested $2 donation with the proceeds going to the Edmond HOPE Center. For more information, contact Edmond Electric at 216-7671 or email michelle.gumaer@edmondok.com.

    April 21, 2014

  • Why do wolves howl?

    Of all the myths that dog the wolf, none is more widely accepted than the idea that wolves howl at the moon. Images of wolves with their heads upturned, singing at the night sky, are as unquestioned as a goldfish's three-second memory or a dog's color-blindness (both also myths).

    April 20, 2014

  • Screen shot 2014-04-18 at 4.44.15 PM.png Paint, doodle and sketch: 3 apps for art lovers

    In the absence of a palette of watercolors and a sketchpad, these three apps can fill in as your art supplies of choice.

    April 20, 2014 1 Photo