Rare events in earth history include the LB1 human skeleton from Flores, Indonesia, as a developmental singularity, not a unique taxon
- aLaboratory for the Study of Morphology, Mechanics and Molecules, Department of Kinesiology, Pennsylvania State University, University Park, PA 16802;
- bSchool of Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia; and
- cKenneth J. Hsü Center for Integrated Hydrological Circuits Development, National Institutes of Earth Sciences, Beijing 100871, China
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Contributed by Kenneth J. Hsü, May 13, 2014 (sent for review November 21, 2013)

Significance
The taxon “Homo floresiensis” was termed “the most important find in human evolution for 100 years.” The name was invented for several fragmentary skeletons found on one Indonesian island, all less than 100,000 y old (some as recent as 12,000 y), all coeval with only Homo sapiens existing everywhere else in the world. Defining taxonomic features appear in just a single specimen, LB1, which has the only known skull and femora. Key features of 380 mL and 1.06 m are shown here to be underestimates, supportable as species-defining only by overlooking asymmetry and disproportion that are general signs of abnormal development. Logically, patent isolated individual abnormality obviates new species status even without diagnosis of a particular syndrome.
Abstract
The original centrally defining features of “Homo floresiensis” are based on bones represented only in the single specimen LB1. Initial published values of 380-mL endocranial volume and 1.06-m stature are markedly lower than later attempts to confirm them, and facial asymmetry originally unreported, then denied, has been established by our group and later confirmed independently. Of nearly 200 syndromes in which microcephaly is one sign, more than half include asymmetry as another sign and more than one-fourth also explicitly include short stature. The original diagnosis of the putative new species noted and dismissed just three developmental abnormalities. Subsequent independent attempts at diagnosis (Laron Syndrome, Majewski osteodysplastic primordial dwarfism type II, cretinism) have been hampered a priori by selectively restricted access to specimens, and disparaged a posteriori using data previously unpublished, without acknowledging that all of the independent diagnoses corroborate the patent abnormal singularity of LB1. In this report we establish in detail that even in the absence of a particular syndromic diagnosis, the originally defining features of LB1 do not establish either the uniqueness or normality necessary to meet the formal criteria for a type specimen of a new species. In a companion paper we present a new syndromic diagnosis for LB1.
Footnotes
- ↵1To whom correspondence may be addressed. Email: eyl{at}psu.edu or kenjhsu{at}aol.com.
↵2Present address: Virginia Tech Carilion School of Medicine, Roanoke, VA 24014.
Author contributions: R.B.E., M.H., and K.J.H. designed research; R.B.E., M.H., A.S.W., and K.J.H. performed research; R.B.E., M.H., and A.S.W. analyzed data; and R.B.E., M.H., and K.J.H. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1407385111/-/DCSupplemental.
Freely available online through the PNAS open access option.
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