Two publications in Nature this week 1,2, a special issue of the Journal of Human Evolution, and a conference at Stony Brook University this past month provide new data on the origins of the curious fossil hominin from Ling Bua Cave, Flores, Indonesia. First announced in 2004 3,4, the LB-1 fossil hominin has been the subject of much debate. Its peculiar stature (est. 30 kg, 1.06 m tall), cranial capacity (417 cm3), age (38,000-18,000 years ago), and location (the remote island of Flores in eastern Indonesia) have led scientists to various interpretations of the fossil 5. Is LB-1 a new hominin species (Homo floresiensis) 3,4? If so, which fossil hominin is its ancestor and how did they arrive on the island of Flores? Alternatively, LB-1 might represent an individual who suffered from a developmental pathology causing her small stature such as Laron syndrome 6.
I was initially skeptical of LB-1’s status as a new species of hominin, yet the two recent Nature publications suggest Homo floresiensis may indeed be a legitimate taxon 1,2. The foot of LB-1 is exceptionally long relative to its femur and tibia and is outside the expected range of variation observed in hominins, but within the range of variation observed in chimpanzees and bonobos 2. While other aspects of its lower limbs suggest that Homo floresiensis was an obligate biped, it may not have had the endurance running capabilities of Homo erectus 2,5. Additionally, evidence from fossil hippopotamus species from Madagascar suggests that the degree of brain size reduction observed in Homo floresiensis is observed in other mammalian species suffering from insular dwarfism 1. In other words, the extremely reduced cranial capacity of H. floresiensis (assuming a late Homo ancestor) can be explained through evolutionary, not pathological, processes.
- Weston, E. M. & Lister, A. M. Insular dwarfism in hippos and a model for brain size reduction in Homo floresiensis. Nature 459, 85-88 (2009).
- Jungers, W. L., Harcourt-Smith, W. E. H., Wunderlich, R. E., Tocheri, M. W., et al. The foot of Homo floresiensis. Nature 459, 81-84 (2009).
- Brown, P., Sutikna, T., Morwood, M. J., Soejono, R. P., et al. A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature 431, 1055-1061 (2004).
- Morwood, M. J., Soejono, R. P., Roberts, R. G., Sutikna, T., et al. Archaeology and age of a new hominin from Flores in eastern Indonesia. Nature 431, 1087-1091 (2004).
- Lieberman, D. E. Homo floresiensis from head to toe. Nature 459, 41-42 (2009).
- Hershkovitz, I., Kornreich, L. & Laron, Z. Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron Syndrome). Am J Phys Anthropol 134, 198-208 (2007).
Here is an interesting video from Science Friday explaining the recent research.
Filed under: Anthropology, Human Evolution, Paleoanthropology | Tagged: hobbits, Homo floresiensis, summertime
Catching up on my blog-readings…
First, I should admit that I didn’t read the Nature articles, and generally try to steer clear of the Hobbit debate entirely because it’s messy and people are mean. As such, I don’t have strong feelings either way, and won’t be remotely upset if you tell me I’m an idiot who doesn’t know enough about the topic to make a legitimate comment.
That said, 1) aren’t most people in agreement that LB1 is a hominin, they just aren’t sure if it’s a pathological human or a descendant of H erectus (which would still make it a hominin, wouldn’t it? Or am I mixing up hominin and hominid again?). Either way, it’s closer to humans, or at least to H erectus, than bonobos, regardless of foot size. 2) I’m not up on the different types of dwarfism, but aren’t dwarfs still considered humans? How is that an “evolutionary” explanation (re: different species explanation) and NOT a pathological one?
If you respond to this, you’ll be in Ethiopia. I’m sad I didn’t see you in the lab before you left. Hope you have a great time and I’ll see you in the fall (or end of the summer – when do you get back?)!