Sunday, February 1, 2009

The ebu gogo of Flores - an unfinished story

The locals knew of them as the ebu gogo, the 'grandmother who eats everything'. At first glance, it appeared to be one of those countless cryptozoological stories of mythical animals. "Probably a large macaque that was mistaken as a human" said the scientists.
In 1998 a team led by Michael Morwood of the University of New England in Armidale, Australia discovered crude stone implements and then followed it up by discovering LB1 (alternatively known as Flo, Hobbit etc.) the skeletal remains in the Liang Bua (LB) limestone caves of the remote island of Flores (see map and picture below) in the Indonesian archipelago. Subsequently, that cave revealed the existence of the skeletons of seven more of these 'hobbits', named because of their exceptionally small body size and height (see pic below).


It was one of the most electrifying findings in anthropology and started one of the most fiercely contested scientific debates over the origins of the little people of Flores. The owner of the bones seemed to have existed as recently as 12,000 years ago, something unimaginable for a primitive hominin, all of which were believed to have been extinct at least 24,000 years back.
One of the greatest mysteries of the modern world finally seems to be showing signs of resolution with the publication of the most recent study by Karen Baab and her colleagues at the Stony Brook University in the Journal of Human Evolution (Jan, 2009). The study addresses the primary bone (couldn’t resist the pun!) of contention among the two camps of scientists and concurs with the initial paper of Morwood which assigns the hobbits the status of a new species altogether - the Homo floresiensis. The opposing camp has vehemently protested this species status claiming that the skeletons were nothing more than pygmy Homo sapiens with microcephaly. What is of interest is the number of scientific papers in respected scientific journals that have gone back and forth proving and disproving the acceptance of this new species. And it hasn't been short of controversies too!
Looking at the immense volume of scientific literature starting from 2004, I have tried to simplify matters by summarising the findings for each year subsequent to the initial announcement of the find in Nature. The studies are colour coded green (agreeing with the hobbit being a new species) and orange (disagreeing on the species status):




2004
Brown, P.; Sutikna, T., Morwood, M. J., Soejono, R. P., Jatmiko, Wayhu Saptomo, E. & Rokus Awe Due . "A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia". Nature 431: 1055

Morwood, M. J.; Soejono, R. P., Roberts, R. G., Sutikna, T., Turney, C. S. M., Westaway, K. E., Rink, W. J., Zhao, J.- X., van den Bergh, G. D., Rokus Awe Due, Hobbs, D. R., Moore, M. W., Bird, M. I. & Fifield, L. K. "Archaeology and age of a new hominin from Flores in eastern Indonesia".
Nature 431: 1087–1091.

Letter to Sunday Mail from M. Henneberg of the University of Adelaide, Australia on October 31st, three days after Nature report attributing the reduced head size to microcephaly

2005"Technical Comments: Comment on "The Brain of LB1, Homo floresiensis"". Science. 2005-10-14

Morwood, M. J.; Brown, P., Jatmiko, Sutikna, T., Wahyu Saptomo, E., Westaway, K. E., Rokus Awe Due, Roberts, R. G., Maeda, T., Wasisto, S. & Djubiantono, T. (2005-10-13). "Further evidence for small-bodied hominins from the Late Pleistocene of Flores, Indonesia".
Nature 437: 1012–1017

Falk, D.; Hildebolt, C., Smith, K., Morwood, M. J., Sutikna, T., Brown, P., Jatmiko, Wayhu Saptomo, E., Brunsden, B. & Prior, F. (
2005). "The Brain of LB1, Homo floresiensis". Science 308 (5719): 242.

2005 was an important year. The first scientific publication challenging Morwood's findings appeared in the form of the technical comments in Science. Till then it was restricted to letters in newspapers and articles in magazines. Dean Falk published her comprehensive study supporting the species status based on a brain pan. It was also the year when the controversy turned ugly with the shenanigans of Teuku Jacob of the Gadja Mada University in Yogyakarta, Java. Jacob was not in the team that made the initial discovery in Liang Bua. However, even before he published scientifically, he was already parroting the 'microcephaly' idea of Henneberg. November, 2004 Jacob had all the delicate skeletal specimens moved from the Indonesian Centre for Archaeology to his own laboratory without the permission of the Centre's Directors. He eventually had to return them after an outcry from other scientists, who knew of his reputation for restricting scientific access to fossils. But by then, the damage was done. Portions of the skeletons were severely damaged with two leg bones completely missing.

2006
Jacob, T.; Indriati, E., Soejono, R. P., Hsu, K., Frayer, D. W., Eckhardt, R. B., Kuperavage, A. J., Thorne, A. & Henneberg, M. (September 5, 2006). "Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities". Proceedings of the National Academy of Sciences, USA 103: 13421–13426

Martin, R. D.; MacLarnon, A. M., Phillips, J. L., Dussubieux, L., Williams, P. R. & Dobyns, W. B. (
May 19, 2006). "Comment on "The Brain of LB1, Homo floresiensis"". Science 312 (5776): 999

Falk, D.; Hildebolt, C., Smith, K., Morwood, M.J., Sutikna, T., Jatmiko, Wayhu Saptomo, E., Brunsden, B. & Prior, F. (2006). "Response to Comment on "The Brain of LB1, Homo floresiensis"".
Science 312: 999c.

Argue, D.; Donlon, D., Groves, C. & Wright, R. (October 2006). "Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo?". Journal of Human Evolution 51: 360–374.


Dean Falk's paper continued to generate debate in the form of 'comments' and 'response to comments' from both camps. Jacob finally published along with various scientists from Australia and United States who attributed virtually everything in the skeletons to 'pathological abnormalities'. Debbie Argue compared the skull of LB1 to various microcephalic skulls and concluded that it indeed deserved the new species status.

2007
Falk, D.; Hildebolt, C.; Smith, K.; Morwood, M.J.; Sutikna, T.; Others, (2007). "Brain shape in human microcephalics and Homo floresiensis". Proceedings of the National Academy of Sciences 104 (7): 2513

Tocheri, M.W.; Orr, C.M.; Larson, S.G.; Sutikna, T.; Others, (2007). "The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution".
Science317 (5845): 1743.

Larson SG, Jungers WL, Morwood MJ, et al (2007). "Homo floresiensis and the evolution of the hominin shoulder". J. Hum. Evol. 53 (6): 718–31.

Hershkovitz I, Kornreich L, Laron Z (2007). "Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron Syndrome)". Am. J. Phys. Anthropol. 134 (2): 198–208.

The important publications that added to the voices supporting the new species view were Tocheri et al. and Larson et al. Tocheri compared the wrist bones and concluded that it was very similar to African apes and early hominin-like wrist rather than modern humans and Neanderthals. Larson et al. found similar results for the shoulder bones. This proved that the hobbits were much more likely to be a new species rather than deformed modern humans.

2008
Lyras GA, Dermitzakis DM, Van Der Geer AAE, Van der Geer SB, De Vos J. 2008. The origin of Homo floresiensis and its relation to evolutionary processes under isolation. Anthropological Science. Published online 1 August 2008.
Hershkovitz I, Kornreich L, Laron Z (2007). "Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron Syndrome)". Am. J. Phys. Anthropol. 134 (2): 198–208.

Obendorf, P.J.; Oxnard, C.E.; Kefford , C.E. (June 7, 2008). "
Are the small human-like fossils found on Flores human endemic cretins?". Proceedings of the Royal Society of London, B Biological Sciences (Online: Royal Society) 275 (1640): 1287-1296.

Lyras study confirmed what Debbie Argue had found by comparing the 3D-morphometrics of a number of microcephalic human skulls with the LB1 skulls. The LB1 skull morphometry was significantly different from microcephalic human skulls. Hershkowitz suggested that the hobbits were in fact afflicted by a hormonal disease called the Laron Syndrome. Similarly, Obendorf et al. proposed that the hobbits were actually born without a functional thyroid, leading to something called 'Cretinism' (and all this time I thought cretin was a swear word!). However the latter two theories didn’t seem to have too many takers.

2009
Baab, K and K. P. McNulty (2009). Size, shape, and asymmetry in fossil hominins: The status of the LB1 cranium based on 3D morphometric analyses. Journal of Human Evolution.
The latest in the series, this paper by Karen Baab looks at 3D morphometrics of the LB1 skull in much the same way as Lyras and Argue. Dr. Baab and colleagues collected 3D landmark data on the LB1 skull and a large sample of fossils representing other extinct hominin species, as well as a comparative sample of modern humans and apes. They performed several analyses of different regions of the skulls. Taken together, these analyses indicated that the LB1 skull shape is that of a scaled down Homo fossil and not a scaled down modern human.
So, is this finally the end? That’s anybody's guess, but as Karen Baab herself remarks, she recognizes that the controversy as to the evolutionary origins of Homo floresiensis will continue, perhaps without an answer.

Updated: 18/08/2014

Was that last paragraph above prophetic or not? So now, after all this time, it seems like the Flores human is not a new species at all. It was just the microcephalic skull of an individual with Downs Syndrome! If you look at my review above, there have been researchers who have come to similar conclusions earlier. How could a peer reviewed paper that announces something as dramatic as a new species of Homo fall so flat? Serious questions need to be raised on the review process for a start.
For the time being, here are some links to the popular articles on the new discoveries as well as the original paper:
http://www.sciencedaily.com/releases/2014/08/140804151510.htm
http://phys.org/news/2014-08-flores-bones-features-syndrome-hobbit.html
http://www.pnas.org/content/early/2014/07/31/1407382111.abstract?sid=b742aa82-5bcd-46cd-a8a3-59b72dec61b2

2 comments:

karthee said...

Wow, that's some decent review you have done there! enjoyed reading...
cheers

sm said...

good info,good to read.