The struggle to understand the Hobbit

via Cosmos, 27 September 2017:

The discovery of Homo floresiensis in 2003 threw up many questions about the history of our own species. More than a decade later, they remain unanswered. Debbie Argue, biological anthropologist at the Australian National University, explains why.

Source: The struggle to understand the Hobbit | Cosmos

[Paper] The affinities of Homo floresiensis based on phylogenetic analyses of cranial, dental, and postcranial characters

This newly published paper by ANUs Debbie Argue has been making the news recently. A new analysis of the bones puts Homo floresiensis closer in time to Homo habilis than it does Homo erectus or Homo Sapiens, which suggests the the Hobbit’s lineage was more ancient than recent.

Although the diminutive Homo floresiensis has been known for a decade, its phylogenetic status remains highly contentious. A broad range of potential explanations for the evolution of this species has been explored. One view is that H. floresiensis is derived from Asian Homo erectus that arrived on Flores and subsequently evolved a smaller body size, perhaps to survive the constrained resources they faced in a new island environment. Fossil remains of H. erectus, well known from Java, have not yet been discovered on Flores. The second hypothesis is that H. floresiensis is directly descended from an early Homo lineage with roots in Africa, such as Homo habilis; the third is that it is Homo sapiens with pathology. We use parsimony and Bayesian phylogenetic methods to test these hypotheses. Our phylogenetic data build upon those characters previously presented in support of these hypotheses by broadening the range of traits to include the crania, mandibles, dentition, and postcrania of Homo and Australopithecus. The new data and analyses support the hypothesis that H. floresiensis is an early Homo lineage: H. floresiensis is sister either to H. habilis alone or to a clade consisting of at least H. habilis, H. erectus, Homo ergaster, and H. sapiens. A close phylogenetic relationship between H. floresiensis and H. erectus or H. sapiens can be rejected; furthermore, most of the traits separating H. floresiensis from H. sapiens are not readily attributable to pathology (e.g., Down syndrome). The results suggest H. floresiensis is a long-surviving relict of an early (>1.75 Ma) hominin lineage and a hitherto unknown migration out of Africa, and not a recent derivative of either H. erectus or H. sapiens.

Source: The affinities of Homo floresiensis based on phylogenetic analyses of cranial, dental, and postcranial characters

See also:

Learn the science of the Hobbit in this free online course

The University of Wollonggong is offering a free online course on the science of Homo floresiensis, one of the most intriguing hominid finds of recent history.

In a cave on the Indonesian island of Flores, a team of archaeologists were surprised to find the skeletal remains of a mysterious new species. This free online course follows the incredible discovery of Homo floresiensis – or ‘the Hobbit’ as it has come to be known. Join us on a quest of discovery and adventure as the mystery is unravelled piece by piece using a variety of scientific techniques and archaeological approaches.

Source: Homo Floresiensis Uncovered – Online Course

Evidence of fire-making in Liang Bua

A microstratigraphic study of the Hobbit cave, Liang Bua, reveals the use of fire between 41,000 and 24,000 years ago. The dates suggest that Homo sapiens used the cave after Homo floresiensis and fueling speculation that modern humans were responsible for the extinction of the hobbits.

Liang Bua. Source: Cosmo Magazine 20160630
Liang Bua. Source: Cosmo Magazine 20160630

Initial micromorphological results from Liang Bua, Flores (Indonesia): Site formation processes and hominin activities at the type locality of Homo floresiensis
Journal of Archaeological Science, 2016 DOI: 10.1016/j.jas.2016.06.004

Fire discovery sheds new light on ‘hobbit’ demise
Science Daily, 29 June 2016

Modern humans may have smoked ‘hobbits’ out of their caves and into extinction
Mother Nature Network, 29 June 2016

Gap Between “Hobbits” and Modern Humans Narrows
The Scientist, 29 June 2016

Fireplace discovery sheds light on hobbits’ demise
Cosmos, 30 June 2016

Humans did wipe out real-life ‘hobbits’, say scientists
The Independent, 1 July 2016

Liang Bua, a karstic cave located on the island of Flores in eastern Indonesia, is best known for yielding the holotype of the diminutive hominin Homo floresiensis from Late Pleistocene sediments. Modern human remains have also been recovered from the Holocene deposits, and abundant archaeological and faunal remains occur throughout the sequence. The cave, the catchment in which it is located and the gross aggradational phases of the sediment sequence have all been subject to a great deal of scientific scrutiny since the discovery of the holotype of H. floresiensis in 2003. A recent program of geoarchaeological research has extended analyses of the site’s deposits to the microstratigraphic (micromorphological) level. The stratigraphic sequence in the cave is well defined but complex, comprising interstratified sediments of diverse lithologies and polygenetic origins, including volcanic tephras, fine-grained colluvium, coarse autogenic limestone gravels, speleothems and anthropogenic sediments, such as combustion features. The sedimentological and chemical heterogeneity suggest that processes of site formation and diagenesis varied markedly through time, both laterally and vertically. We present initial results from samples collected in 2014 from an excavation area near the rear of the cave, which yielded radiocarbon ages from charcoal that fill an important temporal gap in the chrono-stratigraphic sequence of previously excavated areas of the site. The results indicate marked changes in site environment and hominin activity during the Late Pleistocene, relating primarily to the degree to which the cave was connected to the hydrogeological system and to the varying intensities of use of the cave by hominins. Importantly, we identify anthropogenic signs of fire-use at the site between 41 and 24 thousand years ago, most likely related to the presence of modern humans.

Article link here.

Another Hobbit paper argues against Down Syndrome theory

While the excitement was brewing over the discovery of 700,000-year-old hobbit bones in Flores, another paper published at the same time evaluates the theory that H. floresiensis presented with signs of Down Syndrome. The paper noted significant differences between the hominid bones and those with Down Sydrome and concluded that the bones were unique.

A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis
PLoS One, 08 June 2016, doi:10.1371/journal.pone.0155731

Homo floresiensis Remains Unique, Valid Species
Sci-News, 13 June 2016

The Liang Bua hominins from Flores, Indonesia, have been the subject of intense scrutiny and debate since their initial description and classification in 2004. These remains have been assigned to a new species, Homo floresiensis, with the partial skeleton LB1 as the type specimen. The Liang Bua hominins are notable for their short stature, small endocranial volume, and many features that appear phylogenetically primitive relative to modern humans, despite their late Pleistocene age. Recently, some workers suggested that the remains represent members of a small-bodied island population of modern Austro-Melanesian humans, with LB1 exhibiting clinical signs of Down syndrome. Many classic Down syndrome signs are soft tissue features that could not be assessed in skeletal remains. Moreover, a definitive diagnosis of Down syndrome can only be made by genetic analysis as the phenotypes associated with Down syndrome are variable. Most features that contribute to the Down syndrome phenotype are not restricted to Down syndrome but are seen in other chromosomal disorders and in the general population. Nevertheless, we re-evaluated the presence of those phenotypic features used to support this classification by comparing LB1 to samples of modern humans diagnosed with Down syndrome and euploid modern humans using comparative morphometric analyses. We present new data regarding neurocranial, brain, and symphyseal shape in Down syndrome, additional estimates of stature for LB1, and analyses of inter- and intralimb proportions. The presence of cranial sinuses is addressed using CT images of LB1. We found minimal congruence between the LB1 phenotype and clinical descriptions of Down syndrome. We present important differences between the phenotypes of LB1 and individuals with Down syndrome, and quantitative data that characterize LB1 as an outlier compared with Down syndrome and non-Down syndrome groups. Homo floresiensis remains a phenotypically unique, valid species with its roots in Plio-Pleistocene Homo taxa.

Full story here.

Possible Hobbit ancestors found in Flores, dating 700,000 years

A new paper out in Nature last month detail the find of tiny hominid bones in Flores, home of H. floresiensis. The fossils from Mata Menge date to 700,000 years old, and suggest that the hobbit had been older and had a longer history on the island than previously thought.

Mata Menge site. Source: Nature via ABC News 20160609
Mata Menge site. Source: Nature via ABC News 20160609

Homo floresiensis-like fossils from the early Middle Pleistocene of Flores
Nature, 09 June 2006

‘Hobbit’ relatives found after ten-year hunt
Nature, 08 June 2016

Homo floresiensis has been uncovered at the 700,000 year old site of Mata Menge, Flores, Indonesia
Human Evolution @ UCK, 08 June 2016

Flores fossil discovery provides clues to ‘hobbit’ ancestors
The Guardian, 08 June 2016

Flores fossil discovery gives new clue to ‘hobbit’ relatives
AFP, via Economic Times, 09 June 2016

Hobbit discovery: Hopes 700,000-year-old find could shed new light on evolution
ABC News, 09 June 2016

New fossils shed light on the origin of ‘hobbits’
Griffith University, via Popular Archaeology, 09 June 2016

Australian-led team unlocked new questions about human evolution and the history of the`Hobbit’, 10 June 2016

The evolutionary origin of Homo floresiensis, a diminutive hominin species previously known only by skeletal remains from Liang Bua in western Flores, Indonesia, has been intensively debated. It is a matter of controversy whether this primitive form, dated to the Late Pleistocene, evolved from early Asian Homo erectus and represents a unique and striking case of evolutionary reversal in hominin body and brain size within an insular environment1–4. The alternative hypothesis is that H. floresiensis derived from an older, smaller-brained member of our genus, such as Homo habilis, or perhaps even late Australopithecus, signalling a hitherto undocumented dispersal of hominins from Africa into eastern Asia by two million years ago (2 Ma)5,6. Here we describe hominin fossils excavated in 2014 from an early Middle Pleistocene site (Mata Menge) in the So’a Basin of central Flores. These specimens comprise a mandible fragment and six isolated teeth belonging to at least three small-jawed and small-toothed individuals. Dating to ~0.7 Ma, these fossils now constitute the oldest hominin remains from Flores7. The Mata Menge mandible and teeth are similar in dimensions and morphological characteristics to those of H. floresiensis from Liang Bua. The exception is the mandibular first molar, which retains a more primitive condition. Notably, the Mata Menge mandible and molar are even smaller in size than those of the two existing H. floresiensis individuals from Liang Bua. The Mata Menge fossils are derived compared with Australopithecus and H. habilis, and so tend to support the view that H. floresiensis is a dwarfed descendent of early Asian H. erectus. Our findings suggest that hominins on Flores had acquired extremely small body size and other morphological traits specific to H. floresiensis at an unexpectedly early time.

Article link here.

Hobbits older than expected

A new paper in Nature has revised the dates of the Hobbit, once thought to be 12,000 years old, to be an older 50,000 years old. This period roughly coincides with the time modern humans started appearing in the region, and while it’s tempting to think the two events are related it’s still too early to tell.

Excavations of Holocene deposits at Liang Bua
Archaeological excavations of Holocene deposits at Liang Bua on the Indonesian island of Flores are seen in progress in this undated handout picture courtesy of the Liang Bua Team.
Photo: Reuters

Revised stratigraphy and chronology for Homo floresiensis at Liang Bua in Indonesia
Sutikna et al.
Nature, doi:10.1038/nature17179

Suspicious: Hobbits Vanish When Modern Humans Appear
Discovery News, 30 March 2016

Indonesian ‘Hobbits’ may have died out sooner than thought
Griffith University, 30 March 2016

A decade ago, researchers reported that evolutionary cousins of modern humans, nicknamed hobbits, lived until fairly recently in an Indonesian cave
AP, via US News, 30 March 2016

The ‘hobbit’ was a separate species of human, new dating reveals
Science, 30 March 2016

Scientists: New evidence Indonesian ‘Hobbits’ disappeared 50K years ago
KVAL, 31 March 2016

Diminutive ‘Hobbit’ people vanished earlier than previously known, scientists say
Reuters, via Malay Mail, 31 May 2016

Homo Floresiensis: A Profile Of The Extinct ‘Hobbits’ Of Indonesia
Tech Times, 31 May 2016

New Homo Floresiensis Dates May Quash Cryptozoology Theories About ‘Hobbits’
Forbes, 31 May 2016

The ‘hobbits’ were extinct much earlier than first thought
The Conversation AU, 31 March 2016

‘Hobbits’ extinct much earlier than first thought
Australian Geographic, 31 March 2016

Forget Tolkien, the scientific tale of real-life “hobbits” is even more complex
Ars Technica, 01 April 2016

‘Hobbit’ people were no match for the unstoppable juggernaut of modern man
Tech Insider, 04 April 2016

The Hobbit gets a little older, and science a little wiser
The Conversation AU, 05 April 2016

Homo floresiensis, a primitive hominin species discovered in Late Pleistocene sediments at Liang Bua (Flores, Indonesia), has generated wide interest and scientific debate. A major reason this taxon is controversial is because the H. floresiensis-bearing deposits, which include associated stone artefacts and remains of other extinct endemic fauna, were dated to between about 95 and 12 thousand calendar years (kyr) ago. These ages suggested that H. floresiensis survived until long after modern humans reached Australia by ~50 kyr ago. Here we report new stratigraphic and chronological evidence from Liang Bua that does not support the ages inferred previously for the H. floresiensis holotype (LB1), ~18 thousand calibrated radiocarbon years before present (kyr cal. BP), or the time of last appearance of this species (about 17 or 13–11 kyr cal. BP). Instead, the skeletal remains of H. floresiensis and the deposits containing them are dated to between about 100 and 60 kyr ago, whereas stone artefacts attributable to this species range from about 190 to 50 kyr in age. Whether H. floresiensis survived after 50 kyr ago—potentially encountering modern humans on Flores or other hominins dispersing through southeast Asia, such as Denisovans12, 13—is an open question.

Nature paper here.

Cranial analysis of hobbit suggests no relation to modern humans

A new paper published in the Journal of Human Evolution compares the cranial structures of modern humans and homo florsiensis and concludes that the two species are not related.

What do cranial bones of LB1 tell us about Homo floresiensis?
Journal of Human Evolution, doi:10.1016/j.jhevol.2015.12.008

‘Hobbits’, Homo Floresiensis Were Another Species Not Deformed Humans,New Study
National Daily Press, 18 Feb 2016

Homo Floresiensis or ‘Hobbits’ Found on Flores Island were Not Modern Humans, Study Reveals
BiztekMojo, 16 Feb 2016

Cranial vault thickness (CVT) of Liang Bua 1, the specimen that is proposed to be the holotype of Homo floresiensis, has not yet been described in detail and compared with samples of fossil hominins, anatomically modern humans or microcephalic skulls. In addition, a complete description from a forensic and pathological point of view has not yet been carried out. It is important to evaluate scientifically if features related to CVT bring new information concerning the possible pathological status of LB1, and if it helps to recognize affinities with any hominin species and particularly if the specimen could belong to the species Homo sapiens.

Medical examination of the skull based on a micro-CT examination clearly brings to light the presence of a sincipital T (a non-metrical variant of normal anatomy), a scar from an old frontal trauma without any evident functional consequence, and a severe bilateral hyperostosis frontalis interna that may have modified the anterior morphology of the endocranium of LB1. We also show that LB1 displays characteristics, related to the distribution of bone thickness and arrangements of cranial structures, that are plesiomorphic traits for hominins, at least for Homo erectus s.l. relative to Homo neanderthalensis and H. sapiens. All the microcephalic skulls analyzed here share the derived condition of anatomically modern H. sapiens. Cranial vault thickness does not help to clarify the definition of the species H. floresiensis but it also does not support an attribution of LB1 to H. sapiens. We conclude that there is no support for the attribution of LB1 to H. sapiens as there is no evidence of systemic pathology and because it does not have any of the apomorphic traits of our species.

Article here.

Stone tools push the human occupation of Sulawesi back by 60,000 years

The discovery of stone tools from Sulawesi date to 118,000 years ago – possibly by the so-called hobbits – predate what is thought to be the earliest arrival of humans into Southeast Asia 50,000 – 60,000 years ago.

Stone tools dating to 118,000 years from Sulawesi. Source: ABC News 20160114
Stone tools dating to 118,000 years from Sulawesi. Source: ABC News 20160114

Earliest hominin occupation of Sulawesi, Indonesia
Gerrit D. van den Bergh, Bo Li, Adam Brumm, Rainer Grün, Dida Yurnaldi, Mark W. Moore, Iwan Kurniawan, Ruly Setiawan, Fachroel Aziz, Richard G. Roberts, Suyono, Michael Storey, Erick Setiabudi & Michael J. Morwood
Nature, doi:10.1038/nature16448

A group of mysterious humans left these tools in Indonesia over 118,000 years ago
Ars Technica, 15 January 2016

Stone tools found on Sulawesi in Indonesia ‘made by ancient humans at least 118,000 years ago
ABC News, 14 January 2016

‘Hobbit’ gets a neighbor: Stone tools hint at archaic human presence
CS Monitor, 14 January 2016

Ancient tools show how mysterious ‘Hobbit’ occupied Indonesian island
Reuters, via Ottowa Sun, 13 January 2016

Sulawesi is the largest and oldest island within Wallacea, a vast zone of oceanic islands separating continental Asia from the Pleistocene landmass of Australia and Papua (Sahul). By one million years ago an unknown hominin lineage had colonized Flores immediately to the south1, and by about 50 thousand years ago, modern humans (Homo sapiens) had crossed to Sahul2, 3. On the basis of position, oceanic currents and biogeographical context, Sulawesi probably played a pivotal part in these dispersals4. Uranium-series dating of speleothem deposits associated with rock art in the limestone karst region of Maros in southwest Sulawesi has revealed that humans were living on the island at least 40 thousand years ago (ref. 5). Here we report new excavations at Talepu in the Walanae Basin northeast of Maros, where in situ stone artefacts associated with fossil remains of megafauna (Bubalus sp., Stegodon and Celebochoerus) have been recovered from stratified deposits that accumulated from before 200 thousand years ago until about 100 thousand years ago. Our findings suggest that Sulawesi, like Flores, was host to a long-established population of archaic hominins, the ancestral origins and taxonomic status of which remain elusive.

Article can be found here.

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

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.