03/23/2005
Hobbit Revisited
Walking along the shores of the Gulf of Mexico here on Marco Island naturally stirs an interest in maritime topics. Perhaps you were as excited as I was by recent news reports of the discovery of a “sea of ice” on Mars. The reports came from a team of researchers involved with the High Resolution Stereo Camera onboard the European Space Agency’s Mars Express orbiter. The European workers interpret photos from the orbiter as indicating a frozen sea hundreds of miles across, comparable to the size of the North Sea here on Earth. A layer of volcanic ash and sediment covers the frozen “sea”. At least that’s the interpretation of the European team.
Not so fast, say a number of scientists here in the U.S., according to an article by Richard Kerr in the March 4 issue of Science. Planetary scientists Alfred McEwen of the University of Arizona, Laszlo Keszthelyi and Michael Carr, both associated with the U.S. Geological Survey, are skeptical of the claim and maintain that the sea of ice is really just a sea of lava. McEwen says we’ve been through this seven years ago when the Mars Global Surveyor first imaged these areas on Mars. He says that if you lay images of the purported sea on Mars next to images of lava flows in Iceland they look the same. I’m disappointed that there may not be an icy sea on Mars but, hey, controversy is part of the search for the truth in science.
One of the most controversial and shocking findings in science last year was the discovery of the skeletal remains of remarkably small humans in the Liang Bua cave on the island of Flores in Indonesia. We discussed this hobbit-like human, only about three feet tall, back in November (11/10/2004). The Australian- Indonesian team, led by archaeologist Mike Morwood, that discovered the fossil was convinced that this was not a modern Homo sapiens and dubbed it a new species, Homo floresiensis.
Aside from the size, the surprising thing was that the fossil was a mere 18,000 years old. To have a type of human that size and that was not one of us modern humans living among us so recently was a true shock to the scientific community. As we mentioned, the finding generated immediate controversy. One view, shared by a fellow named Teuku Jacob, was that our little guy was not some archaic human that survived until recent times but was actually a modern human pygmy with a disease known as microcephaly.
When we left the story, the Center for Archaeology in Jakarta, repository for the bones, had agreed to let Jacob, an Indonesian paleontologist, take possession of the bones for study in his lab at Gadjah Mada University in the city of Yogyakarta in Indonesia. Morwood and his discovery team colleagues cried foul when the bones were handed over to Jacob in November last year. Jacob claimed that for decades archaeologists had brought bones from the Liang Bua to his lab for anatomical analysis. Articles by Elizabeth Culotta and by Michael Balter in the February 25 and March 4 issues of Science, respectively, shed light on the continuing saga of the tiny bones.
The controversy continues. Three paleoanthropologists, Maciej Henneberg (University of Adelaide), Alan Thorne (Australian National University in Canberra) and Robert Eckhardt (Pennsylvania State University) examined the bones and agreed with Jacob’s view that they are the bones of a diseased modern pygmy. Offhand, this sounds like a devastating critique, which Morwood called mind-boggling.
Morwood seems to have good reason to disagree. Balter’s Science article discusses a study of the cranium of Homo floresiensis just published online by Science. I was taken by the fact that the lead author of the cranium study, Dean Falk, is here in Florida at Florida State University in Tallahassee. How did Falk become involved? It seems that, prior to the bones being turned over to Jacob, Morwood and his colleagues did manage to have the skull of our hobbit scanned at a hospital in Jakarta.
Why is the scan important? The inside surface of the skull preserves the surface features of the brain. Normally, to get a picture of a brain’s surface from a fossil skull one pours liquid rubber into the skull to make a cast of the inner surface of the skull. However, the discovery team considered the skull too fragile for that procedure. Falk’s team, one of whose members was Charles Hildebolt of the Mallinckrodt Institute of Radiology in St. Louis, took the CT scans from Jakarta and made a “virtual endocast” of the hobbit’s brain surface.
They compared their endocast with virtual endocasts of a microcephalic modern human, a modern woman, a Homo erectus, a pygmy and a chimpanzee. The Homo floresiensis brain is no bigger than the chimp’s. The Falk team also had latex casts of the brains of other primates and extinct hominids. Comparison of these various casts convinced the researchers that the hobbit skull is not that of a microcephalic pygmy.
One troubling aspect of Homo floresiensis is that small brain. Conventional wisdom has been that brain size matters. Yet, the researchers found advanced types of stone tools in the same area as the fossils of Homo floresiensis. How could that small brain come up with these tools? Well, the virtual endocast shows that our little hobbit’s brain has large temporal lobes, as well as highly convoluted and folded frontal lobes. These areas of the brain are those which are involved in such activities as understanding speech, undertaking initiatives and planning future actions; in other words, just the characteristics that could lead to the ability to visualize and create sophisticated tools.
Falk is quoted as saying that he hasn’t seen swellings (under the forehead) like this in any extinct hominid endocasts, including those of Homo erectus, one of our early relatively advanced human relatives. One postulated origin of our hobbit is that an earlier hominid, perhaps the tall Homo erectus, came to the island and, because of the limited island resources, gradually shrank in size in order to be able to exist on those resources. You may recall that Flores was home to a miniature elephant as well. The fact that the endocast doesn’t match Homo erectus leads Falk to suggest that our little guy may have evolved from an ancestor that predated H. erectus.
Finally, the microcephalic crowd has not thrown in the towel. Although Falk contends that the skull is “totally the wrong shape” to be a microcephalic, Alan Thorne counters that a single European microcephalic skull doesn’t say anything about the global range of microcephalic virtual endocasts. I may be mistaken, but I seem to recall that Thorne himself is no stranger to controversy and was involved in a fossil find that led him to contradict the prevailing view that all modern humans came out of Africa.
Wouldn’t you know? I had just finished this column when I logged onto AOL and spotted a headline, “Fresh Scandal Over Old Bones” on the USA Today Web site. Sure enough, the article by Dan Vergano dated March 22 was about the hobbit bones. On February 23, Jacob returned all but 4 leg bones to the Jakarta center. The “scandal” includes the fact that there was “irreparable damage” to the bones. Apparently, Jacob made rubber casts of the bones “for display” and in the process there were teeth broken off the skull, missing eye sockets, a smashed pelvis, a broken off chin on another skull glued back on misaligned and other damage. Jacob claims the damage must have been done in transport.
In addition, Jacob also gave a piece of bone to a German researcher for genetic analysis, which apparently violated a 1999 agreement that original hominid fossils would not be transported to other countries without “compelling scientific reasons”. Jacob’s action was described as “completely unethical” and “freeloading on our discovery” by a member of the discovery team. I’m sure we’ve not heard the last of Homo floresiensis!
Allen F. Bortrum
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