Liang Bua

Liang Bua
Cave where the remains of Homo floresiensis were found
Location	Flores, East Nusa Tenggara, Indonesia
Length	50 meters
Discovery	1950s
Geology	Limestone
Entrances	1

Liang Bua is a limestone cave on the island of Flores, Indonesia. The cave is slightly north of the town of Ruteng in Manggarai Regency, East Nusa Tenggara. The cave demonstrated archaeological and paleontological potential in the 1950s and 1960s as described by the Dutch missionary and archaeologist Theodor L. Verhoeven.

The skeleton of a Homo floresiensis woman at the Natural History Museum in London, England.

In September 2003, an Indonesian field team and its coordinator of the excavation team, Thomas Sutikna, uncovered the first indications of a skull. Initially, the archeologists only analyzed the top of the cranium and believed that the skull discovered belonged to a small child due to the small size. However after several days of excavating the skull, Sutikna and his colleagues discovered that its teeth were permanent and mature, revealing that this skull actually belonged to a fully grown adult. After a few weeks, the team had discovered most of this particular hominid's skeleton and later was coded LB1, LB2, etc., after the name of the cave. This skeleton later became the holotype specimen of Homo floresiensis, also known as the "hobbit." Despite the small stature and brain size of Homo floresiensis, they were capable of using stone tools, hunting animals such as small elephants and rodents, and dealing with many predators such as large Komodo Dragons.  Excavations are still being conducted and additional findings such as teeth are being discovered and analyzed.

There has been much debate if the skeletal remains are actually Homo floresiensis or not due to the small nature of these species. Further research and studies are still being conducted to confirm whether these discoveries are Homo floresiensis or not. So far Liang Bua is the only location in which such remains have been identified. Although archeological work in the nearby Soa Valley in Ngada Regency appears to support findings from the Liang Bua site.

History of Discoveries

Theodor L. Verhoeven, a Dutch missionary and archaeologist, was living in Flores in the 1950s and 60s. Verhoeven studied archeology at The University of Utrecht and showed a great interest in it. During this time, he worked at a Catholic Seminary and on his free time, he would explore many archeological sites and perform many excavations in Flores. He discovered stone tools and suspected that Homo erectus from Java were the ones making these stone tools. However, Verhoeven's work was not acknowledged by many paleoanthropologists at this time and/or dismissed his work. After 30 years, an Indonesian-Dutch excavation team discovered new evidence that suggest that Verhoeven's predictions were correct.

In 2001, an Indonesian-Australian team began excavations in Liang Bua. Their goal was to excavate deeper into the cave with the hopes to see if modern or pre-modern humans were using Liang Bua. They were led by Indonesian field coordinator, Thomas Sutikna.

In 2003, Benyamin Tarus, a locally hired worker, was excavating a 2 by 2 meter square and found the first indication of a skull at a depth of 6 meters. At that point, many archeologists stepped in to help carefully remove sediment from the top of the skull. Rokus Due Awe, an Indonesian faunal expert, was called in to help inspect the excavated top portion of the skull. By looking at just the top of the skull, Awe believed it belonged to a small child due to the small size of the cranium. However after several days of excavating, more of the cranium and mandible became exposed. This allowed Awe to further analyze the age and condition the skull was in. They discovered that its teeth were permanent, revealing that this skull actually belonged to a fully matured adult. The team had discovered most of this particular hominid's skeleton and many stone tools that they may have created and used. They were later was coded LB1, LB2, etc., after the name of the cave.

Dr. Peter Brown, an expert on cranial, mandibular, and dental anatomy of early and modern humans was asked to help identify and analyze this new discovery. The skeletal evidence indicates that the adults of these species weighed approximately 66 - 86 pounds, had an average height of 106 cm (3'6") tall, and had very small brains (400 cubic centimeters). Dr. Brown concluded that the proportions between the humerus and femur were very similar to the proportions in Australopithecus and Homo habilis.  The characteristics of this skeleton appeared more similar to early hominins like Australopithecus afarensis than compared to modern humans. This skeleton later became the holotype specimen of Homo floresiensis.

The key specimens that many researchers focus on are LB1 and LB6. LB1 was discovered unfossilized in September 2003 and consisted of an almost complete skull and partial skeleton. Scientists assume that LB1 was an approximately 30 year old female, approximately 3 feet, had a brain volume of about 380 - 420 cc, and weighed approximately 55 pounds.  On the other hand, LB6 consisted of a partial skeleton that appeared shorter than LB1 and its jaw was significantly different as it had a more V- shaped jaw. Scientists assume that LB6 was a child and was approximately five years old.

In 2004 Kira Westaway, a paleoanthropologist at the University of Wollongong, analyzed a thick blanket of sediment that the fossils were found in and discovered that these bones ranged from 18,000 to 38,000 years old. This suggests that these species at Liang Bua were alive during modern times and could have possibly shared this island with modern humans for approximately 30,000 years.

Further Research and Findings

In 2010 and 2011, archaeologists discovered two hominin teeth in the cave that did not come from Homo floresiensis. According to Sutikna, the teeth date to around 46,000 BP and speculate that the teeth are likely to have come from Homo sapiens. Sutikna proposed that Homo sapiens could have coexisted with the "hobbits" for thousands of years and he also proposed that Homo sapiens could have led to the extinction of Homo floresiensis. However, there is no evidence to indicate that and research is still being conducted to prove his hypothesis.

In 2013, a 3D model of the cave created via laser scanning was made available online by the Smithsonian Institution.

In 2016, scientists discovered a lower jaw and teeth from at least one adult and potentially two children in Mata Menge, about 70 kms east of Liang Bua. These findings are dated to about 700,000 years old and could possibly be an early form of Homo floresiensis. Additionally in 2016, Sutikna, Smithsonian researcher Matt Tocheri, and other researchers announced that they concluded that the geological dating at Liang Bua became extinct around 50,000 years ago, which is much earlier than many researchers originally thought. In addition, archaeologists discovered stone tools in the cave that were used from 190,000 to 50,000 years old.

Disagreement

There is continuing disagreement among scientists as to whether or not the discoveries represent a new and distinct hominid species. The disagreement stems from the abnormal size of the skeletal remains found in Liang Bua. At the time, many of the skeletal remains found before were significantly larger. As a result, many researchers doubted the skeletal remains found were actually a new hominid species.

There are many different theories that researchers have created when trying to explain that the skeletal remains found do not represent a new hominid species. Many believe that it is more likely that the bones of the most complete individual found in Liang Bua (individual LB1) are those of a local person who was possibly suffering from a medical condition or a developmental disorder (perhaps Down Syndrome) rather than a unique species of Homo that lived in Flores. LB1 had a small cranial volume, reported as approximately only 380 milliliters, which is about one third less than the average modern human. LB1 has very distinct short thighbones, which is a characteristic seen in those with down syndrome. Robert B Eckhardt, professor of developmental genetics and evolution at Penn state, and his team suggest that the small cranial volume and short thigh bones are consistent with a down syndrome diagnosis. The size of the cranial volume and thigh bones fall within the range of a modern human with down syndrome from the same geographic region. These characteristics are only present in LB1 and not in the other skeletal remains found in Liang Bua. Dr. Eckhardt believes that this is only further evidence that LB1 had down syndrome due to its abnormality.

Another theory that researchers in 2011 suggested was that the species found in Liang Bua actually suffered from microcephaly, a condition where a baby's head is much smaller than expected. To test this, Ralph Holloway, an anthropologist at Columbia University, used a technique called magnetic resonance imaging. Holloway and his team discovered that the skeletal remains found in Liang Bua did not fall within the range for microcephalic humans . As a result, Holloway and his team concluded that the skeletal remains found in Liang Bua most likely did not suffer from microcephaly and the findings are most likely a new set of species. Holloway believed the reason for their abnormal small brain was because their brain was organized differently, which allows them to be more efficient in a smaller space. However, many researchers disagree with Holloway's conclusion believing that there were many confounding variables that were not taken into account when testing for microcephaly in these fossils. Dean Falk, an anthropologist at Florida State University in Tallahassee, critiques Holloway's conclusion believing that Holloway's endocast (a 3D representation of the space within a cavity) was mis-shaped by the cracks and chips present in the ancient fossil head. Falk previously conducted a computed tomography (CT) scan of the Homo floresiensis skull and found that the skeletal evidence found is likely to be a separate species.

One theory during this time was that Homo erectus moved to Flores and overtime their brain began to decrease in size due to island dwarfism, an evolutionary phenomenon that body size decreases significantly over time. However, opponents of this theory argue that Homo erectus's brain would not be able to shrink in relation to its body.

Even so, there are still many researchers that argue that the discoveries in Liang Bua represent a new distinct species that lived in relatively modern times. Sutikna, Smithsonian researcher Matt Tocheri, and other researchers announced that they conclude that the geological dating at Liang Bua became extinct around 50,000 years ago, which would be 10,000 years before Homo sapiens arrived in the region. They believe that their conclusion debunks that the skeletal evidence found in Liang Bua is not a pathologically - dwarfed modern human, but is indeed a new distinct species called Homo floresiensis.

Palaeofauna

• Homo floresiensis
• Stegodon florensis insularis, dwarfed stegodontid proboscidean
• Papagomys theodorverhoeveni, giant rat
• Papagomys armandvillei, giant rat
• Varanus komodoensis, giant varanid lizard
• Leptoptilos robustus, giant marabou stork

Further reading

• Brown, P.; Sutikna, T., Morwood, M. J., Soejono, R. P., Jatmiko, Wayhu Saptomo, E. & Rokus Awe Due (October 27, 2004). "A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia.". Nature, 431. doi:10.1038/nature02999.
• Meijer HJM & R A Due (2010). "A new species of giant marabou stork (Aves: Ciconiiformes) from the Pleistocene of Liang Bua, Flores (Indonesia)". Zoological Journal of the Linnean Society. 160 (4): 707–724. doi:10.1111/j.1096-3642.2010.00616.x.
• Morwood, M. J.; Soejono, R. P., Roberts, R. G., Sutikna, T., Turney, C. S. M., Westaway, K. E., Rink, W. J., Zhao, J.- X., van den Bergh, G. D., Rokus Awe Due, Hobbs, D. R., Moore, M. W., Bird, M. I. & Fifield, L. K. (October 27, 2004). "Archaeology and age of a new hominin from Flores in eastern Indonesia.". Nature 431: 1087–1091. doi:10.1038/nature02956.
• Penny Van Oosterzee; Mike Morwood. A New Human: The Startling Discovery and Strange Story of the "Hobbits" of Flores, Indonesia'. London: Collins. ISBN 0-06-089908-5.
• Knepper, Gert M. (2019): Floresmens - Het leven van Theo Verhoeven, missionaris en archeoloog. ISBN 978-9-46-3892476 (Boekscout, Soest, The Netherlands) (= Verhoeven's biography, in Dutch)