NEWS - The remains of Homo floresiensis found by Australian-New Zealand archaeologist, Professor Mike Morwood (1950-2013) in Liang Bua cave, Flores, in 2003 gradually revealed its evolutionary origins. The very small adult leg bones belonging to the small-brained "Hobbit of Flores" are at least 700,000 years old.
Previous archaeological evidence suggests that these tiny humans inhabited Liang Bua around 50,000 years ago, when Homo sapiens had long settled in southern Australia which ultimately gave rise to much debate about the origins of Flores humans.
A hypothesis is that H. floresiensis is a hybrid of early Asian Homo erectus. Another hypothesis is the remains of a more ancient hominin from Africa before H. erectus and small-bodied from the start. If so, the likely candidates are Homo habilis or Australopithecus afarensis.
Another hominin fossil ever found on Flores is the Mata Menge site 75 km to the east. The earlier site in the tropical grasslands of the So'a Basin yielded several jaw fragments and six teeth excavated from a sandstone layer formed by a small stream flow some 700,000 years ago.
The Mata Menge fossils are dated to 650,000 years earlier than the Liang Bua hominins and are the remains of at least three individuals with jaws and teeth smaller than those of H. floresiensis, suggesting that small body size evolved early in the history of Flores hominins.
However, the Mata Menge and So'a Basin hominin specimens do not provide a link between the early evolution of Flores humans, and some of the teeth are considered transitional between early Asian H. erectus and H. floresiensis.
Yousuke Kaifu of The University Museum in Tokyo, Iwan Kurniawan of the Center for Geological Survey in Bandung, Gerrit D. van den Bergh of the University of Wollongong and team report the discovery of three additional hominin fossils from Mata Menge dating to 700,000 years ago.
Fieldwork at the site over several seasons includes the first postcranial element, the distal shaft of an adult humerus, or lower part of the upper arm bone. The discovery of leg bones from the Mata Menge site has been long-awaited because it could provide important evidence for the ancestral origins of Homo floresiensis.
Digital microscopy of the microstructures shows that the small humerus belonged to an adult individual. The researchers were able to calculate a height of about 100 cm, or about 6 cm shorter than the 60,000-year-old Homo floresiensis skeleton from Liang Bua.
"The 700,000-year-old adult humerus is not only shorter than that of Homo floresiensis, it is also the smallest humerus known from the global hominin fossil record," said Adam Brumm of Griffith University in Brisbane.
"This extremely rare specimen confirms our hypothesis that the ancestors of Homo floresiensis had very small body sizes, suggesting from the small proportions of this limb bone that the early ancestors of the 'Hobbit' were even smaller than we previously thought."
Two teeth from Mata Menge are also small and one has the most characteristic shape in keeping with early H. erectus from Java. This similarity does not support the hypothesis that H. floresiensis evolved from an earlier, more primitive hominin type, which has never been found in Indonesia or indeed anywhere outside Africa.
The human remains from Mata Menge, which now number 10 specimens, come from at least four individuals including two children. All are very similar anatomically to H. floresiensis from Liang Bua and can be considered an older variant. Furthermore, it is clear from the small arm bones that extreme miniaturization of the body occurred early in the history of the Flores hominins.
"The evolutionary history of the Flores hominins is still largely unknown. However, these new fossils strongly suggest that their story did begin when a group of early Asian hominins known as Homo erectus somehow became isolated on this remote Indonesian island, perhaps a million years ago, and underwent a dramatic reduction in body size over time," Brumm said.
Original source:
Yousuke Kaifu, Early evolution of small body size in Homo floresiensis, Nature Communications (2024). DOI:10.1038/s41467-024-50649-7
Previous archaeological evidence suggests that these tiny humans inhabited Liang Bua around 50,000 years ago, when Homo sapiens had long settled in southern Australia which ultimately gave rise to much debate about the origins of Flores humans.
A hypothesis is that H. floresiensis is a hybrid of early Asian Homo erectus. Another hypothesis is the remains of a more ancient hominin from Africa before H. erectus and small-bodied from the start. If so, the likely candidates are Homo habilis or Australopithecus afarensis.
Another hominin fossil ever found on Flores is the Mata Menge site 75 km to the east. The earlier site in the tropical grasslands of the So'a Basin yielded several jaw fragments and six teeth excavated from a sandstone layer formed by a small stream flow some 700,000 years ago.
The Mata Menge fossils are dated to 650,000 years earlier than the Liang Bua hominins and are the remains of at least three individuals with jaws and teeth smaller than those of H. floresiensis, suggesting that small body size evolved early in the history of Flores hominins.
However, the Mata Menge and So'a Basin hominin specimens do not provide a link between the early evolution of Flores humans, and some of the teeth are considered transitional between early Asian H. erectus and H. floresiensis.
Yousuke Kaifu of The University Museum in Tokyo, Iwan Kurniawan of the Center for Geological Survey in Bandung, Gerrit D. van den Bergh of the University of Wollongong and team report the discovery of three additional hominin fossils from Mata Menge dating to 700,000 years ago.
Fieldwork at the site over several seasons includes the first postcranial element, the distal shaft of an adult humerus, or lower part of the upper arm bone. The discovery of leg bones from the Mata Menge site has been long-awaited because it could provide important evidence for the ancestral origins of Homo floresiensis.
Digital microscopy of the microstructures shows that the small humerus belonged to an adult individual. The researchers were able to calculate a height of about 100 cm, or about 6 cm shorter than the 60,000-year-old Homo floresiensis skeleton from Liang Bua.
"The 700,000-year-old adult humerus is not only shorter than that of Homo floresiensis, it is also the smallest humerus known from the global hominin fossil record," said Adam Brumm of Griffith University in Brisbane.
"This extremely rare specimen confirms our hypothesis that the ancestors of Homo floresiensis had very small body sizes, suggesting from the small proportions of this limb bone that the early ancestors of the 'Hobbit' were even smaller than we previously thought."
Two teeth from Mata Menge are also small and one has the most characteristic shape in keeping with early H. erectus from Java. This similarity does not support the hypothesis that H. floresiensis evolved from an earlier, more primitive hominin type, which has never been found in Indonesia or indeed anywhere outside Africa.
The human remains from Mata Menge, which now number 10 specimens, come from at least four individuals including two children. All are very similar anatomically to H. floresiensis from Liang Bua and can be considered an older variant. Furthermore, it is clear from the small arm bones that extreme miniaturization of the body occurred early in the history of the Flores hominins.
"The evolutionary history of the Flores hominins is still largely unknown. However, these new fossils strongly suggest that their story did begin when a group of early Asian hominins known as Homo erectus somehow became isolated on this remote Indonesian island, perhaps a million years ago, and underwent a dramatic reduction in body size over time," Brumm said.
Original source:
Yousuke Kaifu, Early evolution of small body size in Homo floresiensis, Nature Communications (2024). DOI:10.1038/s41467-024-50649-7