Indonesian ‘hobbits’ not related to Homo erectus

The most comprehensive study on the bones of Homo floresiensis, a species of tiny human discovered on the Indonesian island of Flores in 2003, has found that they most likely evolved from an ancestor in Africa and not from Homo erectus as has been widely believed.

Artist's impression of Homo floresiensis [Credit: Katrina Kenny, SA Museum]

The study by The Australian National University (ANU) found Homo floresiensis, dubbed "the hobbits" due to their small stature, were most likely a sister species of Homo habilis -- one of the earliest known species of human found in Africa 1.75 million years ago.

Data from the study concluded there was no evidence for the popular theory that Homo floresiensis evolved from the much larger Homo erectus, the only other early hominid known to have lived in the region with fossils discovered on the Indonesian mainland of Java.

Study leader Dr Debbie Argue of the ANU School of Archaeology & Anthropology, said the results should help put to rest a debate that has been hotly contested ever since Homo floresiensis was discovered.

"The analyses show that on the family tree, Homo floresiensis was likely a sister species of Homo habilis. It means these two shared a common ancestor," Dr Argue said.

"It's possible that Homo floresiensis evolved in Africa and migrated, or the common ancestor moved from Africa then evolved into Homo floresiensis somewhere."

A reconstructed skull of Homo floresiensis [Credit: Stuart Hay, ANU]

Homo floresiensis is known to have lived on Flores until as recently as 54,000 years ago.

The study was the result of an Australian Research Council grant in 2010 that enabled the researchers to explore where the newly-found species fits in the human evolutionary tree.

Where previous research had focused mostly on the skull and lower jaw, this study used 133 data points ranging across the skull, jaws, teeth, arms, legs and shoulders.

Dr Argue said none of the data supported the theory that Homo floresiensis evolved from Homo erectus.

"We looked at whether Homo floresiensis could be descended from Homo erectus," she said.

"We found that if you try and link them on the family tree, you get a very unsupported result. All the tests say it doesn't fit -- it's just not a viable theory."

Dr Argue said this was supported by the fact that in many features, such as the structure of the jaw, Homo floresiensis was more primitive than Homo erectus.

"Logically, it would be hard to understand how you could have that regression -- why would the jaw of Homo erectus evolve back to the primitive condition we see in Homo floresiensis?"

Dr Argue said the analyses could also support the theory that Homo floresiensis could have branched off earlier in the timeline, more than 1.75 million years ago.

"If this was the case Homo floresiensis would have evolved before the earliest Homo habilis, which would make it very archaic indeed," she said.

Professor Mike Lee of Flinders University and the South Australian Museum, used statistical modeling to analyse the data.

"When we did the analysis there was really clear support for the relationship with Homo habilis. Homo floresiensis occupied a very primitive position on the human evolutionary tree," Professor Lee said.

"We can be 99 per cent sure it's not related to Homo erectus and nearly 100 per cent chance it isn't a malformed Homo sapiens," Professor Lee said.

Source: Australian National University [April 21, 2017]

byUnknown

in Anthropology, Early Humans, Human Evolution, Indonesia, Ticker

April 21, 2017

Indonesian ‘hobbits’ not related to Homo erectus

The most comprehensive study on the bones of Homo floresiensis, a species of tiny human discovered on the Indonesian island of Flores in 200...

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Genetic evidence suggests early mammals were nocturnal

Our earliest mammalian ancestors likely skulked through the dark, using their powerful night-time vision to find food and avoid reptilian predators that hunted by day. This conclusion, published by Stanford researchers in Scientific Reports, used genetic data to support existing fossil evidence suggesting that our distant relatives may have adapted to life in the dark.

Many modern mammals, like this wood rat, are nocturnal, thanks to evolutionary developments such as night vision 
in their distant ancestors, Stanford researchers say [Credit: Damian Kuzdak/Getty Images]

The team, led by Liz Hadly, professor of biology and senior author on the paper, examined genes involved in night vision in animals throughout the evolutionary tree, looking for places where those genes became enhanced.

"This method is like using the genome as a fossil record, and with it we've shown when genes involved in night vision appear," Hadly said. "It's a very powerful way of corroborating a story that has been, up to now, only hypothesized."

Mammals versus reptiles

Mammals and reptiles share a common ancestor, with the earliest mammal-like animals appearing in the Late Triassic (about 200 million years ago). Fossil evidence suggests that early mammals had excellent hearing and sense of smell and were likely also warm-blooded. All of these features are common in their descendants, the living mammals, most of whom are nocturnal. Therefore, experts have hypothesized that early mammals were also nocturnal. This study offers direct, genetic evidence for that hypothesis.

To trace the evolution of nocturnality, the researchers studied genes that the lead author, visiting scholar Yonghua Wu, had previously found associated with night vision in certain birds, such as owls. The team members examined those night-vision genes in many mammals and reptiles, including snakes, alligators, mice, platypuses and humans. Using what they know about how those animals are related, they figured out when in their evolutionary histories, if ever, the function of these genes was enhanced.

From this, they deduced that the earliest common ancestor did not have good night vision and was instead active during the day. However, soon after the split, mammals began enhancing their night vision genes, allowing them to begin to roam at night, thus avoiding the reptiles that hunted during the day.

"Early mammals coexisted with early reptiles in the Age of the Dinosaurs and somehow escaped extinction," Wu said. "This research further supports the hypothesis that diurnal reptiles, such as lizards, snakes and their relatives, competed with mammals and may have led them to better adapt to dim light conditions."

In the millions of years that have elapsed since mammals and reptiles diverged, natural selection and evolution haven't stopped. Not all mammals are still nocturnal. Some groups of mammals have reoccupied the day, adapting in various ways to daylight activity. These animals include cheetahs, pikas, camels, elephants, and, of course, humans.

"Understanding the constant pressure to get better at seeing the world at night for over 100 million years is a beautiful way of thinking about evolution," Hadly said. "We think of it as something simple -- seeing in the light or the dark -- but these genes are being constantly refined and altered by natural selection."

Filling in our history

The methods used by these researchers could be applied to different areas of the animal evolutionary tree to learn more about the evolution of vision, including how humans made the switch to bright-light vision. This study is also an example of how little information we have about the first mammals, compared to what we know about our ancient and more compelling reptile cousins, the dinosaurs.

"When people talk about the dinosaur age, even when you look at cartoons, the focus is mainly on dinosaurs," said Haifeng Wang, co-author of the paper and postdoctoral research fellow with Stanley Qi, an assistant professor of bioengineering. "This ancient period is an important piece of the story of our evolution too. We want to know better what the mammals were like then."

Author: Taylor Kubota | Source: Stanford University [April 20, 2017]

byUnknown

in Evolution, Fossils, Genetics, Ticker

April 20, 2017

Genetic evidence suggests early mammals were nocturnal

Our earliest mammalian ancestors likely skulked through the dark, using their powerful night-time vision to find food and avoid reptilian pr...

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Cleveland Museum of Art to transfer Roman sculpture of Drusus Minor to Italy

The Cleveland Museum of Art and The Ministry of Cultural Heritage and Activities and Tourism of the Republic of Italy (Ministry) today announced that they have reached an agreement for the transfer of an early 1st century AD marble portrait head of Drusus Minor (Drusus Julius Caesar, 13 BC-AD 23) to the Republic of Italy.

Head of Drusus Minor (13 BC-AD 23), probably after AD 23 and likely before AD 37. Roman, 1st cent. 
Marble; overall: h. 35 cm (13 3/4 in) [Credit: The Cleveland Museum of Art]

The sculpture, previously sold at a public auction in Paris in 2004, was acquired by CMA in 2012, after extensive research to confirm its ownership history. When the museum acquired the work, it was believed that the sculpture originally came from North Africa. When, more recently, CMA became aware of the fact that the sculpture may have been illicitly removed from a site near Naples towards the end of World War II, the museum promptly contacted the Ministry. Acting in cooperation with officials of the Ministry, and with the assistance of the Carabinieri for the Protection of Cultural Heritage, CMA was able to confirm the World War II events. As a result, CMA determined to transfer the sculpture to Italy

In 2008, the Cleveland Museum of Art entered into a cultural cooperation agreement with the Ministry that formed the basis for a new relationship between CMA and the Republic of Italy. That agreement also provided a framework for the museum to approach the Ministry and obtain the information necessary to allow the museum to decide to transfer the sculpture.

“We have had an excellent relationship with the Ministry for many years,” said William Griswold, CMA director. “When we became aware of facts that were inconsistent with our understanding of the provenance of the sculpture, contacting the Ministry directly was an easy decision in light of our many years of working with our Italian colleagues. We worked collaboratively with the Ministry first to determine the circumstances of the work’s removal and then to finalize the decision to transfer the work.”

"This return is the result of an important and fruitful cultural agreement and the full cooperation of CMA with the Italian authorities,” said the Minister of Cultural Heritage and Activities and of Tourism, Dario Franceschini. “Now we await the return of the work, which, once in Italy will be returned as soon as possible to Naples and its communities, from where it was removed."

Source: The Cleveland Museum of Art [April 19, 2017]

byUnknown

in Archaeology, Europe, Heritage, Italy, Southern Europe, Ticker, USA

April 19, 2017

Cleveland Museum of Art to transfer Roman sculpture of Drusus Minor to Italy

The Cleveland Museum of Art and The Ministry of Cultural Heritage and Activities and Tourism of the Republic of Italy (Ministry) today annou...

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