Teeth study of H. floresiensis unlike any other, suggests new species

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A new study on the tooth morphology of Homo floresiensis suggests that they may be not be a group deformed modern humans, and may also support the theory that the hobbits were derived from Homo erectus undergoing island dwarfism.

Teeth of Homo floresiensis. Source: PLOS One DOI: 10.1371/journal.pone.0141614

Teeth of Homo floresiensis. Source: PLOS One DOI: 10.1371/journal.pone.0141614

Hobbits Were a Separate Species, Ancient Chompers Show
Live Science, 18 November 2015

Fossils Reveal That Ancient Hobbits Were A Separate Species
IFL Science, 19 November 2015

“Hobbit” Teeth Analyzed
Archaeology, 20 November 015

Unique Dental Morphology of Homo floresiensis and Its Evolutionary Implications
Kaifu et al, PLOS One
DOI: 10.1371/journal.pone.0141614

Homo floresiensis is an extinct, diminutive hominin species discovered in the Late Pleistocene deposits of Liang Bua cave, Flores, eastern Indonesia. The nature and evolutionary origins of H. floresiensis’ unique physical characters have been intensively debated. Based on extensive comparisons using linear metric analyses, crown contour analyses, and other trait-by-trait morphological comparisons, we report here that the dental remains from multiple individuals indicate that H. floresiensis had primitive canine-premolar and advanced molar morphologies, a combination of dental traits unknown in any other hominin species. The primitive aspects are comparable to H. erectus from the Early Pleistocene, whereas some of the molar morphologies are more progressive even compared to those of modern humans. This evidence contradicts the earlier claim of an entirely modern human-like dental morphology of H. floresiensis, while at the same time does not support the hypothesis that H. floresiensis originated from a much older H. habilis or Australopithecus-like small-brained hominin species currently unknown in the Asian fossil record. These results are however consistent with the alternative hypothesis that H. floresiensis derived from an earlier Asian Homo erectus population and experienced substantial body and brain size dwarfism in an isolated insular setting. The dentition of H. floresiensis is not a simple, scaled-down version of earlier hominins.

The full paper can be downloaded on PLOS One.

New paper argues against claims of Hobbit Down Syndrome theory

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Skull of LB1. Source: The Conversation 20150210

A new paper in PNAS tears down the arguments made last year in the same journal about the Hobbit being a human with Down Syndrome. The arguments centre around the attributes of LB1 and LB6’s chins. The Conversation piece by the same authors breaks it down nicely.

Skull of LB1. Source: The Conversation 20150210

Skull of LB1. Source: The Conversation 20150210

Down syndrome theory on Hobbit species doesn’t hold to scrutiny
The Conversation, 10 February 2015

Mandibular evidence supports Homo floresiensis as a distinct species
Proceedings of the National Academy of Science, doi: 10.1073/pnas.1418997112

Henneberg et al. (1) and Eckhardt et al. (2) present another pathology-based alternative to the hypothesis that the “hobbit” fossils from Liang Bua, Indonesia, represent a distinct hominin species, Homo floresiensis. They contend that the Liang Bua specimens are the remains of small-bodied humans and that the noteworthy features of the most complete specimen, LB1, are a consequence of Down syndrome (DS). Here, we show that the available mandibular evidence does not support these claims.

Absence of chins in the two mandibles recovered at Liang Bua, LB1 and LB6, is a key issue (1, 3). That these specimens lack chins has been argued to preclude their attribution to Homo sapiens, because a chin is widely accepted to be a defining characteristic of our species (3). Henneberg et al. reject this argument on the grounds that a chin is often absent in living Australo-Melanesians. However, the evidence they present does not support their assertion regarding Australo-Melanesian mandibular morphology. One of two studies they cite has not been peer reviewed (the publication is just a conference abstract), whereas the other one has been severely criticized (4). Henneberg et al. also imply that a mandible from Roonka, Australia, supports their claim, but a CT scan of this specimen shows that it has a positive chin (Fig. 1). Thus, there is no reason to believe that living Australo-Melanesians often lack chins and therefore no reason to overturn Brown and Tomoko’s (3) assessment that the absence of chins in LB1 and LB6 precludes their attribution to H. sapiens.

The link to the paper here.