Clonabile il Mammut lanoso?

Arctic expedition finds 

woolly mammoth remains 

ripe for cloning 

Breakingnews, Early Mammals, Fossils, Genetics, Palaeontology, Russia 


Russian scientists undertaking an exploratory expedition on the Lyakhovsky Islands have discovered woolly mammoth remains including skin and tusk, which they believe suitable for obtaining the DNA necessary to clone the animal. 

The mammoth expedition led by scientists from Russia's North-Eastern Federal  University in Yakutsk, and funded by the Russian Geographical Society  

[Credit: ©: gazetayakutia.ru] 

An international expedition to the Lyakhovsky Islands led by scientists from Russia's North-Eastern Federal University in Yakutsk has discovered six specimens of woolly 
mammoth fossils suitable for extracting DNA.

"The Lyakhovsky Islands are considered the mammoth continent," explained Semyon Grigorev, leader of the expedition to the islands and director of the Mammoth Museum at Russia's North-Eastern Federal University in Yakutsk. "The largest concentration of remains in the world is here, so that's why we chose this area to carry out our studies," Grigorev told a press conference on Wednesday.
 "To start with, together with archeologists we carried out a dig at the most northern site where ancient man lived, not far from the village of Kazachye where we found an enormous amount of mammoth bones, and also ancient tools," said Grigorev of the expedition, which took place over two stages from August 11 to September 29. 

The discovery is seen as highly significant by Russian and South Korean experts  working to bring the mammoths back to life through cloning 

[Credit: NVK]

"Then, after waiting a long time for the right weather conditions, we continued to the main target of our expedition, Great Lyakhovsky Island, where we found a great amount of unique remains," which includes ancient mammoth skin and teeth. 
"Take, for example, the tusk of a pygmy mammoth that we found. We calculate that the animal was no more than two meters tall, so now we have to work out what this was – a micropopulation, or the peculiarity of this single individual." 
"Skin is the most interesting for us, for our project 'The Mammoth Rebirth' because our Korean colleagues consider skin to be the best material for an attempt at cloning via the extraction of viable cells."
 The 'Northern Ecumene' expedition of 16 researchers from six different countries was made possible thanks to a grant of two million rubles provided by the Russian Geographical Society. 
"We consider the expedition a success; after all, out of what seems to be these kinds of small expeditions, great scientific discoveries can be made," said Grigorev, whose team is now joining forces with Korean researchers to analyze the mammoth remains for cells viable for cloning. 

Source: Sputnik News [October 09, 2015]

I primi mammiferi

Earliest-known 

arboreal and subterranean 

ancestral mammals discovered 

  The fossils of two interrelated ancestral mammals, newly discovered in China, suggest that the wide-ranging ecological diversity of modern mammals had a precedent more than 160 million years ago. 

On the left are photos of the type specimen of Docofossor brachydactylus.  Docofossor was found in lake sediments of the Jurassic Ganggou fossil site  in Hebei Province of China. The fossil of Docofossor is preserved with dense  and carbonized furs around its skeleton. On the right is the fossil of  Agilodocodon scansorius. Found in lake sediments of the 165 million  years old Daohugou Fossil Site of Inner Mongolia of China, Agilodocodon  scansorius is preserved with a halo of dense, carbonized furs and hair  impressions. The horny claws on hands and feet are also preserved  [Credit: Zhe-Xi Luo, the University of Chicago] 

With claws for climbing and teeth adapted for a tree sap diet, Agilodocodon scansorius is the earliest-known tree-dwelling mammaliaform (long-extinct relatives of modern mammals). The other fossil, Docofossor brachydactylus, is the earliest-known subterranean mammaliaform, possessing multiple adaptations similar to African golden moles such as shovel-like paws. Docofossor also has distinct skeletal features that resemble patterns shaped by genes identified in living mammals, suggesting these genetic mechanisms operated long before the rise of modern mammals. These discoveries are reported by international teams of scientists from the University of Chicago and Beijing Museum of Natural History in two separate papers published Feb. 13 in Science (the papers can be found here and here). 

Skeletal and life style reconstructions of Agilodocodon scansorius, a docodont mammaliaform.  The skeletal features suggest that it was an agile and active animal living on trees.  Its incisors were specialized to feed on tree sap (exudate feeding), and its molars  suggest omnivorous feeding 

[Credit: April I. Neander/University of Chicago] 

"We consistently find with every new fossil that the earliest mammals were just as diverse in both feeding and locomotor adaptations as modern mammals," said Zhe-Xi Luo, PhD, professor of organismal biology and anatomy at the University of Chicago and an author on both papers. "The groundwork for mammalian success today appears to have been laid long ago." Agilodocodon and Docofossor provide strong evidence that arboreal and subterranean lifestyles evolved early in mammalian evolution, convergent to those of true mammals. These two shrew-sized creatures -- members of the mammaliaform order Docodonta -- have unique adaptations tailored for their respective ecological habitats.

 Skeletal and life style reconstructions of Docofossor brachydactylus. Docofossor lived  in burrows on the lakeshore and fed on the worms and insects in the soil. Docofossor  is also unique in that it has one segment fewer of finger bone segments than most  other mammals, suggesting that it had a unique embryonic development  of its hands and feet [Credit: April I. Neander/University of Chicago] 

Agilodocodon, which lived roughly 165 million years ago, had hands and feet with curved horny claws and limb proportions that are typical for mammals that live in trees or bushes. It is adapted for feeding on the gum or sap of trees, with spade-like front teeth to gnaw into bark. This adaptation is similar to the teeth of some modern New World monkeys, and is the earliest-known evidence of gumnivorous feeding in mammaliaforms. Agilodocodon also had well-developed, flexible elbows and wrist and ankle joints that allowed for much greater mobility, all characteristics of climbing mammals. "The finger and limb bone dimensions of Agilodocodon match up with those of modern tree-dwellers, and its incisors are evidence it fed on plant sap," said study co-author David Grossnickle, graduate student at the University of Chicago. "It's amazing that these arboreal adaptions occurred so early in the history of mammals and shows that at least some extinct mammalian relatives exploited evolutionarily significant herbivorous niches, long before true mammals." 

An illustration of Agilodocodon and Docofossor. The skeletal features  of Agilodocodon (top left) suggeset it was an agile and active  arboreal animal. The skeletal features of Docofossor (bottom right)  suggest it lived in burrows and fed on worms and insects  [Credit: April I. Neander/University of Chicago] 

Docofossor, which lived around 160 million years ago, had a skeletal structure and body proportions strikingly similar to the modern day African golden mole. It had shovel-like fingers for digging, short and wide upper molars typical of mammals that forage underground, and a sprawling posture indicative of subterranean movement. Docofossor had reduced bone segments in its fingers, leading to shortened but wide digits. African golden moles possess almost the exact same adaptation, which provides an evolutionary advantage for digging mammals. This characteristic is due to the fusion of bone joints during development -- a process influenced by the genes BMP and GDF-5. Because of the many anatomical similarities, the researchers hypothesize that this genetic mechanism may have played a comparable role in early mammal evolution, as in the case of Docofossor. The spines and ribs of both Agilodocodon and Docofossor also show evidence for the influence of genes seen in modern mammals. Agilodocodon has a sharp boundary between the thoracic ribcage to lumbar vertebrae that have no ribs. However, Docofossor shows a gradual thoracic to lumber transition. These shifting patterns of thoracic-lumbar transition have been seen in modern mammals and are known to be regulated by the genes Hox 9-10 and Myf 5-6. That these ancient mammaliaforms had similar developmental patterns is an evidence that these gene networks could have functioned in a similar way long before true mammals evolved. "We believe the shortened digits of Docofossor, which is a dead ringer for modern golden moles, could very well have been caused by BMP and GDF," Luo said. "We can now provide fossil evidence that gene patterning that causes variation in modern mammalian skeletal development also operated in basal mammals all the way back in the Jurassic." 

Stem mammaliaforms—also known as stem mammals—are long-extinct relatives to   the extant mammals (crown Mammalia). Docodonts are a lineage of stem mammaliaforms.  Their morphologies provide evidence for the ancestral mammalian condition.  Their functional adaptations provide new insight on the ecological diversification  of the earliest mammals 

[Credit: April I. Neander/University of Chicago]

 Early mammals were once thought to have limited ecological opportunities to diversify during the dinosaur-dominated Mesozoic era. However, Agilodocodon, Docofossor and numerous other fossils -- including Castorocauda, a swimming, fish-eating mammaliaform described by Luo and colleagues in 2006 -- provide strong evidence that ancestral mammals adapted to wide-ranging environments despite competition from dinosaurs. "We know that modern mammals are spectacularly diverse, but it was unknown whether early mammals managed to diversify in the same way," Luo said. "These new fossils help demonstrate that early mammals did indeed have a wide range of ecological diversity. It appears dinosaurs did not dominate the Mesozoic landscape as much as previously thought." 

Author: Kevin Jiang 

Source: University of Chicago [February 14, 2015]

DI CAVALLI, RINOCERONTI E TAPIRI

I Perissodattili (ungulati dispari, relativamente alle zampe posteriori) hanno una comune origine? Sì, e si sapeva già. 

Ma che avessero avuto una comune origine nel sub-Continente Indiano quando questo era ancora un'isola che viaggiava sicura verso l'ineluttabile scontro con il Continente Asiatico (per dare origine alla più alta catena mondiale di montagne), questo è una novità, offerta dalla Johns Hopkins University.

Vi esisteva uno strano animale, il Cambaytherium thewissi  (la cui ricostruzione sembra il disegno di un bambino), che - a quanto sembra - è il più antico progenitore mai scoperto  del gruppo dei perissodattili: la data dei fossili è 54,5 milioni di anni fa.
La scoperta è stata fatta per caso, nel corso di lavori di scavo ai margini di una miniera di carbone, presso Mumbay, in India. I lavori sono stati finanziati dalla National Geographic Society.


Horses and rhinos originated on Asian subcontinent while it was still an island 





Working at the edge of a coal mine in India, a team of Johns Hopkins researchers and colleagues have filled in a major gap in science's understanding of the evolution of a group of animals that includes horses and rhinos.

That group likely originated on the subcontinent when it was still an island headed swiftly for collision with Asia, the researchers report Nov. 20 in the online journal Nature Communications. 

An artist’s depiction of Cambaytherium thewissi  

[Credit: Elaine Kasmer]

Modern horses, rhinos and tapirs belong to a biological group, or order, called Perissodactyla. 
Also known as "odd-toed ungulates," animals in the order have, as their name implies, an uneven number of toes on their hind feet and a distinctive digestive system. Though paleontologists had found remains of Perissodactyla from as far back as the beginnings of the Eocene epoch, about 56 million years ago, their earlier evolution remained a mystery, says Ken Rose, Ph.D., a professor of functional anatomy and evolution at the Johns Hopkins University School of Medicine. 
Rose and his research team have for years been excavating mammal fossils in the Bighorn Basin of Wyoming, but in 2001 he and Indian colleagues began exploring Eocene sediments in Western India because it had been proposed that perissodactyls and some other mammal groups might have originated there. 
In an open-pit coal mine northeast of Mumbai, they uncovered a rich vein of ancient bones. Rose says he and his collaborators obtained funding from the National Geographic Society to send a research team to the mine site at Gujarat in the far Western part of India for two weeks at a time once every year or two over the last decade. 
The mine yielded what Rose says was a treasure trove of teeth and bones for the researchers to comb through back in their home laboratories. 
Of these, more than 200 fossils turned out to belong to an animal dubbed Cambaytherium thewissi, about which little had been known. 
The researchers dated the fossils to about 54.5 million years old, making them slightly younger than the oldest known Perissodactyla remains, but, Rose says, it provides a window into what a common ancestor of all Perissodactyla would have looked like. 
"Many of Cambaytherium's features, like the teeth, the number of sacral vertebrae, and the bones of the hands and feet, are intermediate between Perissodactyla and more primitive animals," Rose says. 
"This is the closest thing we've found to a common ancestor of the Perissodactyla order." Cambaytherium and other finds from the Gujarat coal mine also provide tantalizing clues about India's separation from Madagascar, lonely migration, and eventual collision with the continent of Asia as Earth's plates shifted, Rose says. In 1990, two researchers, David Krause and Mary Maas of Stony Brook University, published a paper suggesting that several groups of mammals that appear at the beginning of the Eocene, including primates and odd- and even-toed ungulates, might have evolved in India while it was isolated. Cambaytherium is the first concrete evidence to support that idea, Rose says. 
But, he adds, "It's not a simple story."
 "Around Cambaytherium's time, we think India was an island, but it also had primates and a rodent similar to those living in Europe at the time," he says. 
"One possible explanation is that India passed close by the Arabian Peninsula or the Horn of Africa, and there was a land bridge that allowed the animals to migrate. 
But Cambaytherium is unique and suggests that India was indeed isolated for a while." Rose said his team was "very fortunate that we discovered the site and that the mining company allowed us to work there," although he added, "it was frustrating to knowing that countless fossils were being chewed up by heavy mining equipment." 
When coal extraction was finished, the miners covered the site, he says. His team has now found other mines in the area to continue digging.



Source: Johns Hopkins Medicine 

[November 20, 2014]

Costolette di mammut.

L'osservazione (recente) che i resti di Mammut presentano coste cervicali con frequenza dieci volte superiore (33,3%) a quella degli odierni elefanti (3,3%), insieme al fatto che tale presenza è in genere dovuta ad inbreeding (riproduzione tra consanguinei) e a gravidanza in cattive condizioni climatiche, ha fatto pensare che i resti di mammut rinvenuti fossero quelli di una popolazione spinta ormai sulla via del declino e dell'estinzione.

In genere, i mammifero (includendo quelli dal collo lungo - come le giraffe - e quelli apparentemente privi di collo - come i delfini-) possiedono 7 vertebre cervicali (con alcune eccezioni: il dudongo, i manatidi ed il bradipo), che sono prive di coste. Il reperimento di una costa cervicale (una costa che è connessa e si articola con una vertebra cervicale) è sempre un evento curioso. 
Le vertebre cervicali, di per sé, non dovrebbero essere dannose (salvo produrre problemi vascolari, talvolta una vera sindrome patologica).
Ma in genere si associano ad altre malformazioni che possono alterare il benessere e la longevità del soggetto portatore.

E' questa l'ipotesi di lavoro dei ricercatori  del Rotterdam Museum of Natural History e del  Naturalis Biodiversity Center di Leiden.

Oh, però: venite numerosi! Non affettiamo il nostro mammut solo  per una o due porzioni...

Neck ribs in woolly mammoths 

provide clues about their decline and extinction 





Researchers recently noticed that the remains of woolly mammoths from the North Sea often possess a 'cervical' (neck) rib—in fact, 10 times more frequently than in modern elephants (33.3% versus 3.3%). 
In modern animals, these cervical ribs are often associated with inbreeding and adverse environmental conditions during pregnancy. If the same factors were behind the anomalies in mammoths, this reproductive stress could have further pushed declining mammoth populations towards ultimate extinction. 

The arrow indicates a large articulation facet of a cervical rib on a fossil cervical vertebra of a woolly mammoth of the Natural History Museum Rotterdam

[Credit: Joris van Alphen]

 Mammals, even the long-necked giraffes and the short-necked dolphins, almost always have seven neck vertebrae (exceptions being sloths, manatees and dugongs), and these vertebrae do not normally possess a rib. 
Therefore, the presence of a 'cervical rib' (a rib attached to a cervical vertebra) is an unusual event, and is cause for further investigation. A cervical rib itself is relatively harmless, but its development often follows genetic or environmental disturbances during early embryonic development.
 As a result, cervical ribs in most mammals are strongly associated with stillbirths and multiple congenital abnormalities that negatively impact the lifespan of an individual. 

Researchers from the Rotterdam Museum of Natural History and the Naturalis Biodiversity Center in Leiden examined mammoth and modern elephant neck vertebrae from several European museum collections.
 "It had aroused our curiosity to find two cervical vertebrae, with large articulation facets for ribs, in the mammoth samples recently dredged from the North Sea. 
We knew these were just about the last mammoths living there, so we suspected something was happening. Our work now shows that there was indeed a problem in this population", said Jelle Reumer, one of the authors on the study published today in the open access journal PeerJ. 
 The incidence of abnormal cervical vertebrae in mammoths is much higher than in the modern sample, strongly suggesting a vulnerable condition in the species. 
Potential factors could include inbreeding (in what is assumed to have been an already small population) as well as harsh conditions such as disease, famine, or cold, all of which can lead to disturbances of embryonic and fetal development.
 Given the considerable birth defects that are associated with this condition, it is very possible that developmental abnormalities contributed towards the eventual extinction of these late Pleistocene mammoths. 

Source: PeerJ [March 25, 2014]

Read more at: http://archaeologynewsnetwork.blogspot.it/2014/03/neck-ribs-in-woolly-mammoths-provide.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+TheArchaeologyNewsNetwork+(The+Archaeology+News+Network)#.UzPk1qh5OSo
Follow us: @ArchaeoNewsNet on Twitter | groups/thearchaeologynewsnetwork/ on Facebook

Dieta del Mammut nel permafrost

What our frozen past tells us about the Ice Age diet 

of the woolly mammoth 


  Research into 50,000 years of arctic vegetation has identified the plant life that sustained giant Ice Age animals such as the woolly mammoth. 

Woolly mammoth [Credit: University of Sussex] 

University of Sussex Professor of Permafrost Science Julian Murton is one of the authors of an international research paper published in the journal Nature today. The study presents a 50,000-year record of arctic vegetation history based on the first circumpolar ancient environmental DNA study of plant diversity from permafrost sediments. Professor Murton says: "Permafrost acts like a giant freezer, preserving countless plant and animal remains from which we can build a record that covers millennia." The study challenges the prevailing view that the Ice Age "mammoth steppe" (which fed the Ice Age megafauna – giant mammals including woolly mammoths, woolly rhinoceros, bison and horse) was grass-dominated. 

Maps showing yedoma distribution [Credit: University of Sussex]

 Instead, the DNA analysis reveals that the dry steppe tundra on which the animals lived and fed was dominated by forbs (herbaceous vascular plants that are not grasses, sedges and rushes), which provided more nutrients to the grazing animals than grasses. One such forb whose Ice Age DNA remains occur in Siberian permafrost is Plantago canescens (Northern Plantain). After the Ice Age ended about 10,000 years ago and many of the megafauna became extinct the forb-rich vegetation was replaced with moist tundra vegetation dominated by woody plants, grasses, sedges and mosses. Permafrost sediments were collected by drilling into geological exposures at 21 field sites, mostly in Siberia, Alaska and Canada. Professor Murton's role was to evaluate the geology and permafrost history of the eastern Siberian site of Duvanny Yar in order to provide a geological context for interpreting the DNA results. Exceptional exposures of permafrost here provided 81 the of 242 permafrost samples in the study, as well as mammoth tusk and even the buried larders of Ice Age ground squirrels. 

A field worker holds part of a mammoth tusk [Credit: University of Sussex] 

Here, Professor Murton discusses the significance of permafrost sediments to Ice Age history and greenhouse gas emissions, while study co-author Professor Mary Edwards (Professor of Physical Geography at the University of Southampton) describes the nature of the ice-age ecosystem that was the home of mammoths and woolly rhino. Q What and where is permafrost? Permafrost is ground that remains at or below 0°C for two years or more. The permafrost region in the Northern Hemisphere occupies about 23 million square kilometres (24 per cent of the exposed land area), underlying vast areas of Siberia, Canada and Alaska. The thickness of permafrost reaches 1.5 km in central Siberia. Q What are permafrost sediments? The permafrost sediments being studied consist of silt and sand rich in organic carbon and ice. These sediments are known by the Russian term yedoma and occupy a region of about 1 million square kilometres (four times the UK's area) in central and eastern Siberia, as well as large parts of central and northern Alaska and the Klondike region of Yukon, Canada. Collectively, these areas represent the Ice Age subcontinent of Beringia, which included a wide land bridge linking Siberia to Alaska. Q In what environmental conditions did yedoma form? Yedoma formed during the last Ice Age (about 80,000–13,000 years ago) by year-on-year accumulation of silt accompanied by upward growth of permafrost. Silt accumulation at the key yedoma site of Duvanny Yar in eastern Siberia resulted mainly from wind action. Ice Age Earth was windier than at present, with massive dust clouds generated in cold permafrost regions of the Northern Hemisphere. 
The dust settled on and was trapped by vegetation. 

Plantago canescens (Northern Plantain) [Credit: University of Sussex] 

The yedoma at Duvanny Yar formed part of a huge belt of windblown silt that stretched across much of the permafrost zone in the Northern Hemisphere, from eastern England in the west across northern Europe to Siberia and North America. Permafrost still occurs within the Siberian yedoma, but has long since thawed in the windblown silts of England and NW and central Europe. Q What does permafrost tell us about Ice Age history? Yedoma preserves an exceptional record of Ice Age history. Permafrost acts like a giant freezer, preserving countless plant and animal remains of the past ecosystem of Beringia. Such remains include carcasses and bones of the woolly mammoth, woolly rhinoceros and many other mammals as well as fossil rodent burrows. More abundant still are tiny pollen grains, insect remains and microbial communities immobilised on the surface of ancient seeds. 

Scientists examining thawing permafrost sediments at Duvanny Yar, eastern Siberia [Credit: University of Sussex] 

Regeneration of whole fertile plants from 30,000-year-old fruit tissue preserved in Siberian yedoma demonstrates the important role for such permafrost as a depository for an ancient gene pool. Additionally, the ancient environmental DNA preserved in the permafrost provides a record of past vegetation communities, as described in the Nature paper. Such environment DNA derives mainly from plant remains above and below ground and from animal skin cells and excrement, and is thought to be local in origin. In permafrost environments the DNA is not leached out of the sediments by percolating water, but remains in place, making the permafrost sediments ideal for ancient DNA studies. Q Why is permafrost important to understanding climate warming? Permafrost sediments and soils contain more than twice the amount of the carbon that is present in the atmosphere. With high latitudes warming faster than other regions of the planet, the frozen carbon pool is vulnerable to permafrost thaw and release of the greenhouse gases carbon dioxide and methane. Such release may increase the concentration of greenhouse gases in the atmosphere and amplify climate warming and permafrost thaw – an example of positive feedback. To investigate these processes, the University of Sussex is studying the impact of permafrost thaw on carbon cycling and greenhouse gas emissions from arctic and boreal regions (Carbon Cycling Linkages of Permafrost Systems, CYCLOPS) as part of the NERC Artic Research Programme.

Source: University of Sussex [February 06, 2014]

Read more at: http://archaeologynewsnetwork.blogspot.it/2014/02/what-our-frozen-past-tells-us-about-ice.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+TheArchaeologyNewsNetwork+(The+Archaeology+News+Network)#.UvVd64sn9Z8
Follow us: @ArchaeoNewsNet on Twitter | groups/thearchaeologynewsnetwork/ on Facebook

Espansione dell'uomo ed interbreeding

Did the Denisovans Cross Wallace's Line?

Scientists have proposed that the most recently discovered ancient human relatives -- the Denisovans - somehow managed to cross one of the world's most prominent marine barriers in Indonesia, and later interbred with modern humans moving through the area on the way to Australia and New Guinea.

Three years ago the genetic analysis of a little finger bone from Denisova cave in the Altai Mountains in northern Asia led to a complete genome sequence of a new line of the human family tree -- the Denisovans. Since then, genetic evidence pointing to their hybridisation with modern human populations has been detected, but only in Indigenous populations in Australia, New Guinea and surrounding areas. In contrast, Denisovan DNA appears to be absent or at very low levels in current populations on mainland Asia, even though this is where the fossil was found.

Published today in a Science opinion article, scientists Professor Alan Cooper of the University of Adelaide in Australia and Professor Chris Stringer of the Natural History Museum in the UK say that this pattern can be explained if the Denisovans had succeeded in crossing the famous Wallace's Line, one of the world's biggest biogeographic barriers which is formed by a powerful marine current along the east coast of Borneo. Wallace's Line marks the division between European and Asian mammals to the west from marsupial-dominated Australasia to the east.

Wallace's line delineates Australian and Southeast Asian fauna. The probable extent of land at the time of the last glacial maximum, when the sea level was more than 110 m lower than today, is shown in grey. The deep water of the Lombok Strait between Bali and Lombok formed a water barrier even when lower sea levels linked the now-separated islands and landmasses on either side [Credit: Maximilian Dörrbecker/WikiCommons]

"In mainland Asia, neither ancient human specimens, nor geographically isolated modern Indigenous populations have Denisovan DNA of any note, indicating that there has never been a genetic signal of Denisovan interbreeding in the area," says Professor Cooper, Director of the University of Adelaide's Australian Centre for Ancient DNA. "The only place where such a genetic signal exists appears to be in areas east of Wallace's Line and that is where we think interbreeding took place -- even though it means that the Denisovans must have somehow made that marine crossing."

"The recent discovery of another enigmatic ancient human species Homo floresiensis, the so-called Hobbits, in Flores, Indonesia, confirms that the diversity of archaic human relatives in this area was much higher than we'd thought," says Professor Stringer, Research Leader in Human Origins, Natural History Museum, in London. "The morphology of the Hobbits shows they are different from the Denisovans, meaning we now have at least two, and potentially more, unexpected groups in the area.

"The conclusions we've drawn are very important for our knowledge of early human evolution and culture. Knowing that the Denisovans spread beyond this significant sea barrier opens up all sorts of questions about the behaviours and capabilities of this group, and how far they could have spread."

"The key questions now are where and when the ancestors of current humans, who were on their way to colonise New Guinea and Australia around 50,000 years ago, met and interacted with the Denisovans," says Professor Cooper.

"Intriguingly, the genetic data suggest that male Denisovans interbred with modern human females, indicating the potential nature of the interactions as small numbers of modern humans first crossed Wallace's Line and entered Denisovan territory."

Source: University of Adelaide [October 17, 2013]