Homo Floresiensis, again

[John Grehan]

For those interested, a recent posting from another server on Homo floresiensis. 

John Grehan

> Many list members may not have access to _The Scientist_, the online
> science news service that focuses mainly on biological issues. Therefore,
> below I've reprinted the essential contents of their article (published
> today) about the ongoing controversies concerning Homo floresiensis.
> -----------------------------------------------
> The Scientist
> Volume 19 | <http://www.the-scientist.com/2005/2/28>Issue 4 | 14 | Feb.
> 28,
> 2005
> 
> Researchers wrangle over access to Homo floresiensis
>          by Tabitha M. Powledge
> 
> [The article begins by summarizing the well-publicized seizure of the
> bones
> of H. floresiensis by Teuku Jacob. The release of the bones for study by
> other scientists, promised by January 1, has apparently not been kept as
> of
> the publication of this news article. Jacob has claimed that the small
> scale of the bones reflect an individual who was a microcephalic H.
> sapiens, and not a new species.]  Jacob says that the archaeological
> center's skeletal finds have been referred to his lab for more than 40
> years. "In July 2004 the center persuaded us to pack and transport them
> [the bones] carefully to our lab," he says. One reason was fear that the
> bones would be spirited abroad and become difficult to recover. As for
> access, Jacob declares that scientists around the world have done research
> in the paleontology collections at Gajah Mada, which are particularly rich
> in H. erectus fossils. Robert Eckhardt of Pennsylvania State University
> recounts that Jacob has twice invited him to come study the Flores find.
> Indonesian researchers discovered the bones, and Australian scientists did
> many of the analyses. Michael Morwood of the University of New England in
> Australia writes in an E-mail: "The excavation team has no plans to ask
> Prof Jacob for access to our finds." Morwood reports that Jacob promised
> to
> return the bones on Jan. 1, 2005, a deadline that Tony Djubiantono,
> director of the Indonesian Center for Archaeology, has extended more than
> once.
> 
> [Morwood and others have suggested that skeleton LB 1 is a miniature
> descendant of H. erectus.] "Probably not," says Jeffrey Schwartz, of the
> University of Pittsburgh, who has intensively studied fossils attributed
> to
> H. erectus. LB1 is "like a Rube Goldberg version of hominids," he
> declares.
> "When I look at its features I just don't know what to do with it."
> Schwartz says the knee is apelike, the pelvic region is hominid-like, but
> not like sapiens, and the teeth are unlike any in the fossil record
> attributed either to hominids or apes. "The only thing that looks H.
> sapiens about this to me is the thinness of the cheekbones below the eye
> and the concavity of that region below the eye." He's not even sure about
> LB1's gender. The researchers had concluded that LB1 is female, but
> Schwartz says the pelvis strikes him as intermediate between male and
> female.
> 
> "I am open to any interpretation until the research is complete," says
> Etty
> Indriati, of Jacob's lab, who is studying the Flores remains. She thinks
> LB1's skull is more modern than archaic, and the incisor and canine teeth
> and molars are sapiens-like, too. A lower premolar is peculiar, but wide
> variation is common in those teeth. Brain size, which she measured at 430
> cubic centimeters, is smaller than any known for erectus or sapiens, and
> hence she is leaning to the microcephalic hypothesis.
> 
> If LB1 is an example of microcephaly in the Homo genus, it's like none
> ever
> reported before. Geoffrey Woods, neurogeneticist at the University of
> Leeds, UK, says the head seems in proportion to the body, and surviving
> for
> three decades suggests that LB1 probably was not mentally deficient. That
> makes LB1 quite unlike the people he studies, who have primary
> microcephaly, or people with similar disorders. Woods notes, however, that
> "it is impossible to be sure." William Dobyns, neurogeneticist at the
> University of Chicago, says the researchers dismissed microcephaly too
> quickly as an explanation for LB1's chimp-like cranial capacity. He
> suggests that it's similar to microcephalic osteodysplastic primordial
> dwarfism type II (MOPD II). The usual MOPD II skeletal abnormalities are
> not all present, Dobyns acknowledges, but the head is so extremely small
> that it's reasonable to diagnose a midget microcephalic H. sapiens if not
> MOPD II, then some other syndrome that has yet to be described.
> 
> "There is no way this could be MOPD II," says Judith Hall, medical
> geneticist at the University of British Columbia in Vancouver, who has
> studied the autosomal recessive condition thoroughly. She points out that
> the skull bones are not thin enough for MOPD II. Moreover, few people with
> MOPD II survive for long, and there are no known cases of reproduction
> among them. Hall says LB1 strikes her as similar to known groups of
> isolated Central Americans who are tiny as a result of poor nutrition, and
> whose small size can persist for generations even when their diet
> improves.
> Indonesia is also home to groups of small people.
> 
> Publication of other finds made last year at the Flores site may or may
> not
> help. "With the remains of at least six H. floresiensis individuals
> represented between 74 and 12 kyr, it is very clear that we are not
> dealing
> with a pathological [microcephalic] dwarf as has been claimed," Morwood
> notes. But Maciej Henneberg, paleoanthropologist at the University of
> Adelaide in Australia, points out that these individuals are represented
> by
> small bone fragments, and one by a single tooth. "Neither of those other
> individuals has a braincase preserved to show its small size, while some
> long bones, though small in comparison with an average modern person, are
> well within the range observed in H. sapiens."
> 
> Perhaps details of the brain will clarify classification. These details
> can
> be imprinted inside the braincase, and researchers can reproduce them on
> endocranial casts. Peter Brown, of the University of New England, made a
> brain endocast last year. "In this case, the question will be whether the
> morphology of the cerebral cortex (as reflected on the endocast) appears
> apelike or more like a miniature version of a human brain. Brain size in
> living primates, including humans, does have a small, but significant,
> correlation with cognitive abilities. But a more important factor is the
> organization, wiring, and neurochemistry of the brain in question,
> regardless of its size," Dean Falk explains. Falk, a paleoanthropologist
> at
> Florida State University in Tallahassee, is collaborating with Morwood and
> Brown on endocast studies and reports that a paper on the topic is under
> review.
> 
> RECOVERING DNA DNA studies won't explain everything, but mitochondrial DNA
> could at least reveal whether H. floresiensis is actually a tiny H.
> sapiens. Mitochondrial (mt)DNA recovered from Neandertal fossils is quite
> different from H. sapiens mtDNA, and researchers have argued that it
> demonstrates Neandertals were not part of the human lineage. Alan Cooper,
> the ancient DNA specialist at Oxford who is carrying out the discovery
> team's studies, says that H. erectus mtDNA should also look very different
> compared to H. sapiens mtDNA.
> DNA recovery is a long shot. The hot, wet conditions at Liang Bua are the
> worst possible for preserving it, and moving the specimens from place to
> place increases chances of contaminating it with extraneous sequences. At
> press time, Jacob reportedly had permitted Svante Pääbo's lab at the Max
> Planck Institute for Evolutionary Anthropology, Leipzig, Germany, to
> attempt DNA studies on the Flores bones.
> Cooper says he is hopeful that his own research can proceed, too. Early
> soil results, he says, are encouraging. "Mostly I think we got DNA from
> plants in the sediments. But it's kind of good because at least it means
> potentially DNA is capable of surviving at the site." Cooper had hoped to
> get permission to drill into a Liang Bua hominid tooth (a successful
> strategy in other ancient species) in search of DNA that has been
> protected
> from the elements. But now he says, "Because of all the complications with
> the actual material, we haven't gotten any further on that. I'm still
> optimistic we will in the long term, but there's a good bit of politics to
> be sorted out there."