Falkland Islands wolves mystery solved


Old Falkland wolf family tree

From Wildlife Extra:

Mystery solved – Where did Falkland Islands wolves come from?

Ancient DNA solves 320-year-old mystery

March 2013. University of Adelaide researchers have found the answer to one of natural history’s most intriguing puzzles – the origins of the now extinct Falkland Islands wolf and how it came to be the only land-based mammal on the isolated islands – 460km from the nearest land, Argentina.
Previous theories have suggested the wolf somehow rafted on ice or vegetation, crossed via a now-submerged land bridge or was even semi-domesticated and transported by early South American humans.

Darwin questions

The 320-year-old mystery was first recorded by early British explorers in 1690 and raised again by Charles Darwin following his encounter with the famously tame species on his Beagle voyage in 1834.

New stuffed specimen found in New Zealand

Researchers from the University’s Australian Centre for Ancient DNA (ACAD) extracted tiny pieces of tissue from the skull of a specimen collected personally by Darwin. They also used samples from a previously unknown specimen, which was recently re-discovered as a stuffed exhibit in the attic of Otago Museum in New Zealand.

16,000 years ago

The findings concluded that, unlike earlier theories, the Falkland Islands wolf (Dusicyon australis) only became isolated about 16,000 years ago around the peak of the last glacial period.

“Previous studies used ancient DNA from museum specimens to suggest that the Falkland Islands wolf diverged genetically from its closest living relative, the South American maned wolf (Chrysocyon brachyurus) around seven million years ago. As a result, they estimated that the wolf colonised the islands about 330,000 years ago by unknown means,” says Associate Professor Jeremy Austin, Deputy Director of ACAD and co-lead author with Dr Julien Soubrier.

“Critically, however, these early studies hadn’t included an extinct relative from the mainland, the fox-like Dusicyon avus. We extracted ancient DNA from six specimens of D. avus collected across Argentina and Chile, and made comparisons with a wide group of extinct and living species in the same family.”

ACAD’s analyses showed that D. avus was the closest relative of the Falkland Islands wolf and they separated only 16,000 years ago – but the question of how the island colonisation came about remained. The absence of other mammals argued against any land bridge connection to the mainland.

Eureka moment

“The Eureka moment was finding evidence of submarine terraces off the coast of Argentina,” says study leader Professor Alan Cooper. “They recorded the dramatically lowered sea levels during the Last Glacial Maximum (around 25-18,000 years ago).”

“At that time, there was a shallow and narrow (around 20km) strait between the islands and the mainland, allowing the Falkland Islands wolf to cross when the sea was frozen over, probably while pursuing marine prey like seals or penguins. Other small mammals like rats weren’t able to cross the ice.”

The study was published in Nature Communications.

Chinese dinosaur age bird discovery


This video is called The Fabulous Chinese Fossils— Chaoyang, Liaoning Province.

Sulcavis geeorum skull, photo credit: Stephanie Abramowicz

By Alan McStravick for redOrbit.com – Your Universe Online:

First Fossil Bird Discovered With Teeth For A Tough Diet

January 7, 2013

A trip to the Galapagos islands will bring you face to face with 14 closely related species of finch that Charles Darwin discovered on his adventure abroad in the 1830s. The finches he noted, still referenced in essentially every biology textbook, had beak sizes of varying lengths and sizes. This was true of both the ground- and tree-dwelling birds, and Darwin postulated that differing diets might have required the birds’ unique beaks for their specialized feeding tasks.

It was these birds, catalogued in 1835, that first helped Darwin to arrive at his theory of evolution. He was able to realize that each of the finch species had originally arisen from one ancestral form and that each of the successive forms – with their individual ecological niches and diets – were what he considered the most perfect examples of adaptive radiation, the process where one species undergoes several distinct changes to survive and thrive in a wider variety of habitats.

If Darwin had lived some 121-125 million years ago, he might have experienced the same sense of wonder at the site

rather: sight

of a Sulcavis geeorum, a species of early bird that existed in the Liaoning Province of what is now modern-day China. It was here that a new fossil discovery was made showing that these early ancestors of the dinosaurs

This should be “descendants of the dinosaurs”. Dinosaurs were ancestral to birds; not the other way round.

had evolved teeth adapted to their specialized diets.

In a report of the finding published in the latest issue of the Journal of Vertebrate Paleontology, researchers say they believe that S. geeorum existed on a so-called ‘durophagous diet’, one that included lots of prey with hard exoskeletons such as insects or crabs.

S. geeorum was an enantiornithine bird, a primitive group of early birds that were abundant in the Mesozoic era and carried over into the Cretacious.

Cretaceous

With the discovery of S. geeorum, researchers are enjoying their own Darwin-like moment as they see this discovery as representing a huge leap forward in the known diversity of tooth shape in early birds. This diversity of shape also leads them to believe that they may have stumbled upon an as yet unrecognized degree of ecological diversity.

According to the research team, S. geeorum is the first fossilized bird discovery that has ornamented tooth enamel. Looking back to the specific dinosaurs from which birds are believed to have evolved, researchers find that their tooth structure was specialized mainly for a carnivorous diet. The enanitiornithine family of birds have undergone the most minimal tooth reductions from their dinosaur cousins compared to any other extinct or extant groups of birds, and they also displayed a wide diversity of individual dental patterns.

In this newest enantiornithine discovery, researchers say that they have discovered a robust set of teeth that are marked with grooves on the inside surface. It is from these grooves, they hypothesize, that the teeth received their strength that allowed them to ingest harder food items.

“While other birds were losing their teeth, enantiornithines were evolving new morphologies and dental specializations. We still don’t understand why enantiornithines were so successful in the Cretaceous but then died out – maybe differences in diet played a part,” according to Jingmai O’Connor, lead author of the new study. One thing that is known is that until this discovery, no previous known bird species had preserved ridges, striations, serrated edges, or any other form of dental ornamentation.

“This study highlights again how uneven the diversity of birds was during the Cretaceous. There are many more enantiornithines than any other group of early birds, each one with its own anatomical specialization,” said the study’s co-author Luis Chiappe, from Natural History Museum of Los Angeles County.

Naturalist Alfred Wallace on the Internet


This video is called Operation Wallacea – Indonesia schools expedition.

From Wildlife Extra:

Historic collection of naturalist Alfred Wallace goes online for the first time

Treasure-trove of writings and images by the co-discoverer of natural selection

October 2012. The complete works of the great naturalist Alfred Russel Wallace have been made freely available online on the Wallace Online website.

First announcement of the theory of evolution by natural selection

Amongst the thousands of pages of writings, it includes the first announcement of the theory of evolution by natural selection.

Wallace and Darwin

Since the scientist’s death 99 years ago, Wallace’s complete publications have never been gathered together. The new website is unveiled in time for the centenary celebrations in 2013 that mark the anniversary of Wallace’s death in 1913.

Back in the 1850s, Wallace independently formulated the theory of evolution by natural selection during a fit of tropical fever. He later sent an outline of the theory – in one of the greatest ironies in history – to Charles Darwin. To avoid a priority dispute, papers by both men were read together at a London scientific meeting in July 1858. The event unleashed the Darwinian revolution whose shockwaves continue to this day.

Wallace has long been in the shadow of his more famous contemporary Charles Darwin. The compilation of this new website is timely and long overdue. It provides 28,000 pages of searchable historical documents and 22,000 images. They can now be seen free of charge by anyone around the globe at Wallace Online.

Wallace’s contributions to biodiversity

Wallace spent four years as a collector in Brazil (1848-1853) and eight years in Southeast Asia (1854-1862). In addition to collecting an astonishing 125,000 specimens of insects and birds, Wallace proposed a sharp dividing line between the Asian and Australian animals in the archipelago. This line still bears his name today and is called The Wallace Line.

One of the most influential scientists in history

Dr van Wyhe, project director, said: “Wallace was one of the most influential scientists in history. But until now, it has been impossible to see all of his writings. For the first time, this collection allows anyone to search through his writings about Singapore, Malaysia and Indonesia, and see many of the birds and insects that he collected.”

Dr van Wyhe holds a joint appointment as Senior Lecturer at NUS’ Department of Biological Sciences and the Department of History, under Faculty of Science and Faculty of Arts and Social Sciences, respectively. He is also the founder and director of the award-winning Darwin Online at the University of Cambridge, UK.

This project was directed by historian Dr John van Wyhe from the National University of Singapore (NUS). The Wallace Online project was made possible by an anonymous grant from an American donor.

Galapagos tortoise Lonesome George dies


This video is about the Galapagos islands and the tortoise Lonesome George.

From the BBC:

24 June 2012 Last updated at 22:25 GMT

Last Pinta giant tortoise Lonesome George dies

Staff at the Galapagos National Park in Ecuador say Lonesome George, a giant tortoise believed to be the last of its subspecies, has died.

Scientists estimate he was about 100 years old.

Park officials said they would carry out a post-mortem to determine the cause of his death.

With no offspring and no known individuals from his subspecies left, Lonesome George became known as the rarest creature in the world.

For decades, environmentalists unsuccessfully tried to get the Pinta Island tortoise to reproduce with females from a similar subspecies on the Galapagos Islands.

Park officials said the tortoise was found dead in his corral by his keeper of 40 years, Fausto Llerena.

While his exact age was not known, Lonesome George was estimated to be about 100, which made him a young adult as the subspecies can live up to an age of 200.

Galapagos icon

Lonesome George was first seen by a Hungarian scientist on the Galapagos island of Pinta in 1972.

Environmentalists had believed his subspecies (Chelonoidis nigra abingdoni) had become extinct.

Lonesome George became part of the Galapagos National Park breeding programme.

After 15 years of living with a female tortoise from the nearby Wolf volcano, Lonesome George did mate, but the eggs were infertile.

He also shared his corral with female tortoises from Espanola island, which are genetically closer to him than those from Wolf volcano, but Lonesome George failed to mate with them.

He became a symbol of the Galapagos Islands, which attract some 180,000 visitors a year.

Hunted to extinction

Galapagos National Park officials said that with George’s death, the Pinta tortoise subspecies has become extinct.

They said his body would probably be embalmed to conserve him for future generations.

Tortoises were plentiful on the Galapagos islands until the late 19th century, but were later hunted for their meat by sailors and fishermen to the point of extinction.

Their habitat furthermore suffered when goats were introduced from the mainland.

The differences in appearance between tortoises from different Galapagos islands were among the features which helped the British naturalist Charles Darwin formulate his theory of evolution.

Some 20,000 giant tortoises of other subspecies still live on the Galapagos.

See also here. And here. And here.

The rarest animal in the world is no more. Lonesome George, the last of the Pinta Island tortoises, was found dead on Sunday. But a small hope remains for his subspecies, as its genes have survived: here.

Giant tortoise death casts shadow over Galapagos Islands: here.

Last-of-Its-Kind Tortoise Gets Royal Treatment from Taxidermists [Slide Show]. Preserving an iconic animal like Lonesome George is all about the details: here.

Darwin’s lost fossil plants rediscovered


From the BBC:

16 January 2012 Last updated at 20:16 GMT

Lost Charles Darwin fossils rediscovered in cabinet

A “treasure trove” of fossils – including some collected by Charles Darwin – has been re-discovered in an old cabinet.

The fossils, lost for some 165 years, were found by chance in the vaults of the British Geological Survey HQ near Keyworth, UK.

They have now been photographed and are available to the public through a new online museum exhibit released today.

The find was made by the palaeontologist Dr Howard Falcon-Lang.

Dr Falcon-Lang, who is based in the department of earth sciences at Royal Holloway, University of London, spotted some drawers in a cabinet marked “unregistered fossil plants”.

“Inside the drawer were hundreds of beautiful glass slides made by polishing fossil plants into thin translucent sheets,” Dr Falcon-Lang explained.

“This process allows them to be studied under the microscope. Almost the first slide I picked up was labelled ‘C. Darwin Esq’.”

The item turned out to be a piece of fossil wood collected by Darwin during his famous Voyage of the Beagle in 1834. This was the expedition on which he first started to develop his theory of evolution.

In the course of his visit to Chiloe Island, Chile, Darwin encountered “many fragments of black lignite and silicified and pyritous wood, often embedded close together”.

He had these shipped back to England where they were cut and ground into thin sections.

Joseph Hooker, a botanist and a close friend of Darwin, was responsible for assembling the “lost” collection while he briefly worked for the British Geological Survey in 1846.

The fossils became “lost” because Hooker failed to number them in the formal specimen register before setting out on an expedition to the Himalayas.

The collection was moved several times and gradually became forgotten.

Dr John Ludden, executive director of the Geological Survey said: “This is quite a remarkable discovery. It really makes one wonder what else might be hiding in our collections.”

See also here. And here. And here.

Talking about geology: A rare mineral thought to exist only on the Moon’s surface has been discovered in West Australia’s Pilbara: here.

Inspired by a 2009 colloquium on microbial evolution convened at the Galapagos Islands, a new book from ASM Press, Microbes and Evolution: The World That Darwin Never Saw celebrates Charles Darwin and his landmark publication On the Origin of Species. The editors compiled 40 first-person essays, written by microbiologists with a passion for evolutionary biology, to illuminate how each scientist’s thinking and career paths in science were influenced by Darwin’s seminal work: here.