Homo Floresiensis

Journal of Human Evolution 51 (2006) 360e374

Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo?
Debbie Argue a,*, Denise Donlon b, Colin Groves a, Richard Wright b
a

School of Archaeology & Anthropology, Australian National University, Canberra, ACT 0200, Australia
b
Department of Anatomy and Histology, University of Sydney, NSW 2006, Australia
Received 27 March 2005;accepted 17 April 2006

Abstract
The remarkable partial adult skeleton (LB1) excavated from Liang Bua cave on the island of Flores, Indonesia, has been attributed to a new
species, Homo floresiensis, based upon a unique mosaic of primitive and derived features compared to any other hominin. The announcement
precipitated widespread interest, and attention quickly focused on its possibleaffinities. LB1 is a small-bodied hominin with an endocranial
volume of 380e410 cm3, a stature of 1 m, and an approximate geological age of 18,000 years. The describers [Brown, P., Sutikna, T., Morwood,
M.J., Soejono, R.P., Jatmiko, Wayhu Saptomo, E., Awe Due, R., 2004. A new small-bodied hominin from the Late Pleistocene of Flores,
Indonesia. Nature 431, 1055e1061] originally proposed that H.floresiensis was the end product of a long period of isolation of H. erectus
or early Homo on a small island, a process known as insular dwarfism. More recently Morwood, Brown, and colleagues [Morwood, M.J., Brown,
P., Jatmiko, Sutikna, T., Wahyu Saptomo, E., Westaway, K.E., Awe Due, R., Roberts, R.G., Maeda, T., Wasisto, S., Djubiantono, T., 2005. Further evidence for small-bodied hominins from the LatePleistocene of Flores, Indonesia. Nature 437, 1012e1017] reviewed this assessment in
light of new material from the site and concluded that H. floresiensis is not likely to be descended from H. erectus, with the genealogy of the
species remaining uncertain. Other interpretations, namely that LB1 is a pygmy or afflicted with microcephaly, have also been put forward.
We explore the affinities of LB1using cranial and postcranial metric and non-metric analyses. LB1 is compared to early Homo, two microcephalic humans, a ‘pygmoid’ excavated from another cave on Flores, H. sapiens (including African pygmies and Andaman Islanders), Australopithecus, and Paranthropus. Based on these comparisons, we conclude that it is unlikely that LB1 is a microcephalic human, and it cannot be
attributed to anyknown species. Its attribution to a new species, Homo floresiensis, is supported.
Ó 2006 Elsevier Ltd. All rights reserved.
Keywords: H. floresiensis; Liang Bua 1; LB1; H. habilis; Australopithecus; H. erectus; H. sapiens; H. ergaster; Microcephalic; Multivariate statistics; Phylogenetic
analysis; Insular island dwarfism

Introduction
In October 2004 a remarkable partial adult skeleton fromexcavations in Liang Bua cave on the island of Flores, Indonesia, was described (Brown et al., 2004). Liang Bua 1 (LB1),
dated to 18 ka by Accelerator Mass Spectrometry (AMS) radiocarbon dating and bracketed by luminescence ages of
34 Æ 4 ka and 14 Æ 2 ka (Morwood et al., 2004), is described
as a small-bodied hominin with an endocranial volume (380e
* Corresponding author.
E-mail addresses:debbie.argue@anu.edu.au (D. Argue), ddonlon@anatomy.
usyd.edu.au (D. Donlon), colin.groves@anu.edu.au (C. Groves), richwrig@tig.
com.au (R. Wright).
0047-2484/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jhevol.2006.04.013

410 cm3) and stature (1 m) similar to, or smaller than, Australopithecus afarensis. LB1 has, however, substantially reduced
facial height andprognathism compared to A. afarensis, and
it lacks the masticatory adaptations of that species. Brown
and colleagues (2004) attribute LB1 to a new species, H. floresiensis, based upon a unique mosaic of primitive and derived
features compared with other hominins. As such, H. floresiensis could be the end product of a long period of isolation of H.
erectus or early Homo, a process known as...