A paper published online, on
Monday this week (1) brings us closer to an understanding of who the diminutive
humans, Homo floresiensis were.
The tiny hominids, popularly known as the ‘Hobbits’ died out
between 19,000 and 17,000 on the island of Flores in Indonesia.
Homo floresiensis female reconstruction by John Gurche. Photo by
Chip Clark (3).
Here’s the abstract:
Cranial vault thickness (CVT) of
Liang Bua 1, the specimen that is proposed to be the holotype of Homo
floresiensis, has not yet been described in detail and compared with samples of
fossil hominins, anatomically modern humans or microcephalic skulls. In
addition, a complete description from a forensic and pathological point of view
has not yet been carried out. It is important to evaluate scientifically if
features related to CVT bring new information concerning the possible
pathological status of LB1, and if it helps to recognize affinities with any hominin
species and particularly if the specimen could belong to the species Homo
sapiens.
Medical examination of the skull based on a
micro-CT examination clearly brings to light the presence of a sincipital T (a
non-metrical variant of normal anatomy), a scar from an old frontal trauma
without any evident functional consequence, and a severe bilateral hyperostosis
frontalis interna that may have modified the anterior morphology of the
endocranium of LB1. We also show that LB1 displays characteristics, related to
the distribution of bone thickness and arrangements of cranial structures, that
are plesiomorphic traits for hominins, at least for Homo erectus s.l. relative
to Homo neanderthalensis and H. sapiens. All the microcephalic skulls analyzed
here share the derived condition of anatomically modern H. sapiens. Cranial
vault thickness does not help to clarify the definition of the species H.
floresiensis but it also does not support an attribution of LB1 to H. sapiens.
We conclude that there is no support for the attribution of LB1 to H. sapiens
as there is no evidence of systemic pathology and because it does not have any
of the apomorphic traits of our species.
Micro-CT scan of LB1 showing thickening of the frontal bone, from
Balzeau and Charlier, et. al et al 2016 (1)
The authors Balzeau and Charlier,
et. al. used high-resolution images recently generated in Japan to compute maps
of bone thickness variation, study skull morphology and look for any abnormalities
such as microcephaly, as postulated by Vannuccia et. al. (2).
Overall the authors concluded that:
- The species is completely distinct from humans Homo sapiens. In other words they are not a small version of us
- The individual studied and by inference, Homo floresiensis as a species is not a human suffering from microcephaly
- The individual studied (LB1) had Hyperostosis frontalis interna. This is interesting as this is a common, benign thickening of the inner side of the frontal bone of the skull. It is found predominantly in women after menopause and is usually asymptomatic. Perhaps therefore, this condition is an ancient one occurring in a number of species on the Homo line?
- The studied individual had suffered a healed scar from a frontal skull trauma that had apparently not caused any functional consequence
In an interview for Agence
France-Presse, Balzeau said he could not exclude the possibility that the
"hobbit" was a scaled-down version of Homo erectus, which arrived on the neighbouring island of Java some
million years ago, nor could they be sure that H. floresiensis was not a species it its own right.
Comparison of Homo floresiensis
(L) and modern human (R)
Photo credit: Professor Peter
Brown/University of New England
References
1. Balzeau, A and Charlier P.
2016 What do cranial bones of LB1 tell us about Homo floresiensis? Journal of
Human Evolution Volume 93, April 2016, Pages 12–24
2. Vannuccia, C. et. al. 2011. Craniometric
ratios of microcephaly and LB1, Homo floresiensis, using MRI and endocasts. Proceedings
of the National Academy of Sciences of the United States of America vol. 108
no. 34
3. Retrieved from: http://www.gurche.com/content_homo_floresiensis_657.htm
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