Homo floresiensis
Critics of the claim for species status continue to believe that these individuals are Homo sapiens possessing pathologies of anatomy and physiology. A 2nd hypothesis in this category is that the individuals were born without a functioning thyroid, resulting in a type of endemic cretinism.
Sophisticated stone implements of a size considered appropriate to the 3-foot-tall human are also widely present in the cave. The implements are at horizons from 95,000 to 13,000 years ago and are associated with an elephant of the extinct genus Stegodon (which was widespread throughout Asia during the Quaternary), presumably the prey of LB1. They also shared the island with giant rats, Komodo dragons, and even larger species of lizards. Homo sapiens reached the region by around 45,000 years ago.Homo floresiensis was unveiled on 28 October 2004, and was swiftly nicknamed the "Hobbit", after the fictional race popularized in J. R. R. Tolkien's book The Hobbit, and a proposed scientific name for the species was Homo hobbitus. It was initially placed in its own genus, Sundanthropus floresianus, but reviewers of the article felt that the cranium, despite its size, belonged in the genus Homo.
The 1st set of remains to have been found, LB1, was chosen as the type specimen for the proposed species. LB1 is a fairly complete skeleton, including a nearly complete cranium, determined to be that of a 30-year-old female. LB1 has been nicknamed the Little Lady of Flores or "Flo".
An indicator of intelligence is the size of Brodmann's area 10, the dorsomedial prefrontal cortex, an area of the brain associated with higher cognition. LB1's region 10 is about the same size as that of modern humans, despite the much smaller overall size of the brain.
Additional features used to argue that the finds come from a population of previously unidentified hominids include the absence of a chin, the relatively low twist of the arm bones, and the thickness of the leg bones. The presence of each of these features has been confirmed by independent investigators but their significance has been disputed.
Tocheri et al. examined three carpal bones believed to belong to LB1. The shapes of these bones were claimed to differ significantly from the bones of the modern human wrist and to resemble the wrist of great African apes or Australopithecus.
In early December 2004, Indonesian paleoanthropologist Teuku Jacob removed most of the remains from their repository, Jakarta's National Research Centre of Archaeology, with the permission of only one of the project team's directors and kept them for three months. Some scientists expressed the fear that important scientific evidence would be sequestered by a small group of scientists who neither allowed access by other scientists nor published their own research. Jacob returned the remains on February 23, 2005 with portions severely damaged and missing two leg bones to the worldwide consternation of his peers.
Reports noted the condition of the returned remains; "[including] long, deep cuts marking the lower edge of the Hobbit's jaw on both sides, said to be caused by a knife used to cut away the rubber mould"; "the chin of a 2nd Hobbit jaw was snapped off and glued back together. Whoever was responsible misaligned the pieces and put them at an incorrect angle"; and, "The pelvis was smashed, destroying details that reveal body shape, gait and evolutionary history" and causing the discovery team leader Morwood to remark "It's sickening, Jacob was greedy and acted totally irresponsibly".
Jacob, however, denied any wrongdoing. He stated that the damages occurred during transport from Yogyakarta back to Jakarta despite the physical evidence to the contrary that the jawbone had been broken while making a mould of bones.
In 2005 Indonesian officials forbade access to the cave. Some news media, such as the BBC, expressed the opinion that the reason for the restriction was to protect Jacob, who was considered "Indonesia's king of palaeoanthropology", from being proven to be wrong. Scientists were allowed to return to the cave in 2007 shortly after the death of Jacob.
In response, Weber et al. conducted a survey the same year comparing the computer model of LB1's skull with a sample of microcephalic human skulls, concluding that the skull size of LB1 falls in the middle of the size range of the human samples and isn't inconsistent with microcephaly. Next to dispute the finding of Falk et al. were Martin et al. (2006), who objected to the failure to compare the model of LB1's skull with a typical example of adult microcephaly. Martin and his coauthors concluded that the skull was probably microcephalic, arguing that the brain is far too small to be a separate dwarf species; if it were, the 400-cubic-centimeter brain would indicate a creature only one foot in height, one-third the size of the discovered skeleton. Shortly thereafter, a group of scientists from Indonesia, Australia, and the United States came to the same conclusion by examining bone and skull structure (Jacob (2006)).
In 2013, a comparison of the LB1 endocast to a set of 100 normocephalic and 17 microcephalic endocasts by Vannucci, Baron and Holloway showed that there is a wide variation in microcephalic brain shape ratios and that in these ratios the group as such isn't clearly distinct from normocephalics. The LB1 brain shape nevertheless aligns slightly better with the microcephalic sample, with the shape at the extreme edge of the normocephalic group.
Affected people, who were born without a functioning thyroid, have both small bodies and reduced brain size but their mental retardation and motor disability isn't as severe as with neurological endemic cretins. According to the authors of the study, the critical environment could have been present on Flores approximately 18,000 years ago, the period to which the LB fossils are dated. They wrote that various features found on the fossils, such as enlarged pituitary fossa, unusually straight and untwisted tops of the upper arm bone and relatively thick limbs, are signs of this diagnosis. The double rooted lower premolar and primitive wrist morphology can be explained in this way as well. The oral stories about strange human-like creatures may also be a record of cretinism.
Falk challenged the premise of Oberndorf et al. Studying computer tomography scans of LB1's pituitary fossa, she came to the conclusion that it isn't larger than usual.
In a paper delivered to the Australasian Society for Human Biology in 2009, Colin Groves and Catharine FitzGerald compared the Flores bones with those of ten people who had had cretinism, focusing on anatomical features which are typical of the disease. They found no overlap, and stated that they had put the claim to rest. However, an article by Oxnard, Obendorf and Kefford rejects Groves and FitzGerald's argument and revives the cretinism hypothesis. Oxnard and colleagues also criticise the cladistic analysis of Argue et al., stating that it isn't logically possible for the analysis to conclude that the Liang Bua remains represent a separate species and not a pathology because the cladistics analysis assumes that they don't represent a pathology.
Evidence supports the hypothesis that Homo floresiensis is a late-surviving species of early Homo with shared morphological similarities of the early African pre-erectus/ergaster hominins. This hypothesis provides a more reasonable explanation for H. floresiensis than previously established hypotheses about genetic mutations, diseases, and disordered growth. None of the current explanations account for the range of features observed in H. floresiensis, nor do they provide explanations for why a pathological condition in modern humans would mimic so closely the morphology observed in earlier hominins.
Susan G. Larson et al. analyzed the upper limb of LB1. They found that in LB1 the angle of humeral torsion is much less than in modern humans. This had been previously studied by Richards et al., who declared that it is a sign of modern pygmy populations, and T. Jacob et al., who pointed out that muscle attachments on the bone suggest LB1 had weak muscles which resulted in little development of humeral torsion. Larson et al. rejected Richards’ conclusion, arguing that the humeral torsion of pygmy populations is usually similar to that of peoples of average stature. They argued that Richards et al. cited a 1972 paper which had studied a sample of six female Eastern Central African pygmies and this sample was too small to represent the whole population. Larson et al. also failed to find signs of microcephaly on the studied bones.
In around 2006, two teams attempted to extract DNA from a tooth discovered in 2003, but both teams were unsuccessful. It has been suggested that the happened because the dentine was targeted; new research suggests that the cementum has higher concentrations of DNA. Moreover, the heat generated by the high speed of the drill bit may have denatured the DNA.
In October 2012, a New Zealand scientist due to give a public lecture on Homo floresiensis was told by the Tolkien Estate that he wasn't allowed to use the word "hobbit" in promoting the lecture.
In 2012, the American studio The Asylum, which produces low-budget "mockbuster" films, planned to release a movie entitled Age of the Hobbits depicting a "peace loving" community of H. floresiensis "enslaved by the Java Men, a race of flesh-eating dragon-riders." The film was intended to piggyback on the success of Peter Jackson's film The Hobbit: An Unexpected Journey. The film was blocked from release due to a legal dispute about using the word "hobbit." The Asylum argued that the film didn't violate the Tolkien copyright because the film was about H. floresiensis, "uniformly referred to as 'Hobbits' in the scientific community." The film was later retitled Clash of the Empires.
Related Sites for Homo floresiensis
- Hominid Species - talk.origins read Homo floresiensis
- Face-to-Face with Homo Floresiensis | Anthropology | Sci-News.com read Homo floresiensis
- Homo Floresiensis - Indonesia off the beaten track tours by Incito ... read Homo floresiensis
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