|
Descent of Man In this lecture, beginners can familiarize themselves with basic information and terms used to describe the evolution of humanity beginning with the origin of primates through the comings and goings of Genus Homo. |
Flat-faced Man in family feud
Posted: Friday, March 28, 2003
28 March 2003, REX DALTON, www.nature.com
Palaeontologist claims geology set human relative apart.
A leading palaeontologist is questioning the heritage of a 3.5-million-year-old fossil skull hailed two years ago as a new human relative1. It's just one example, he suggests, of scientists being too quick to give us a bushy family tree.
The fossil hit the headlines in 2001 when Meave Leakey of National Museums of Kenya and colleagues described it as evidence of a new human-like lineage. They named their specimen Kenyanthropus platyops2 - literally, the 'Flat-faced Man of Kenya'.
Tim White of the University of California, Berkeley, now argues that K.platyops was more probably a Kenyan variant of one of the most famous human ancestors of all time - 'Lucy', discovered in Ethiopia in 1974. This fossil skeleton was formally named Australopithecus afarensis3.
Geology, not genes, gave the Flat-faced Man his distinctive looks, White reckons. Over time, he explains, fine-grained rock invaded tiny cracks in the skull and distorted its shape in an irregular way.
White has seen the Flat-faced Man, but has not conducted a full study. His suggestions are based mainly on the state of other fossils, especially some 30-million-year-old skulls of flat-headed pig relatives called oreodonts found in the early 1900s in the western United States. These were "flattened and narrowed by geological deformation, not natural selection", White says.
It is plausible that the same process has muddled the K. platyops story, says Elwyn Simons, who studies primate evolution at Duke University in Durham, North Carolina. Once again, he says, "the evidence may not support the description of a new genus".
Hominid specialist Bernard Wood of George Washington University in Washington DC agrees that geological processes altered the skull, but points out that Leakey's team knew that.
"What is at issue is whether that alteration materially affects if this is a new genus," he says - a question he feels unable to answer on current evidence. Nor does Wood think the case is made for the skull being Lucy's cousin.
These differences of opinion are the latest instalment of the long-running dispute over the diversity of human origins. White, Leakey and many of the world's leading hominid researchers will continue the debate next month at the annual meeting of the Paleoanthropology Society in Tempe, Arizona.
Rex Dalton is the West Coast Correspondent of the journal Nature
References
White, T. Early Hominids - Diversity or Distortion?. Science, 299, 1994 - 1997, (2003).|Homepage|
Leakey, M. G.. et al. New hominin genus from eastern Africa shows diverse middle Pliocene lineages. Nature, 410, 433, (2001).|Article|
Johanson, D. C. & Taieb, M. Plio-Pleistocene hominid discoveries in Hadar, Ethiopia. Nature, 260, 293 - 297, (2003).
© Nature News Service / Macmillan Magazines Ltd 2003
http://www.nature.com/nsu/030324/030324-10.html
Send page by E-Mail
