Mum and Dad Dinosaurs Shared the Work
May 15, 2013 — A study into the brooding behaviour of birds has revealed their dinosaur ancestors shared the load when it came to incubation of eggs.
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Research into the incubation behaviour of birds suggests the type of parental care carried out by their long extinct ancestors.
The study aimed to test the hypothesis that data from extant birds could be used to predict the incubation behaviour of Theropods, the group of carnivorous dinosaurs from which birds descended.
The paper, out today in Biology Letters, was co-authored by Dr Charles Deeming and Dr Marcello Ruta from the University of Lincoln’s School of Life Sciences and Dr Geoff Birchard from George Mason University, Virginia.
By taking into account factors known to affect egg and clutch size in living bird species, the authors — who started their investigation last summer at the University of Lincoln’s Riseholme campus — found that shared incubation was the ancestral incubation behaviour. Previously it had been claimed that only male Theropod dinosaurs incubated the eggs.
Dr Deeming said: “In 2009 a study in the journal Science suggested that it was males of the small carnivorous dinosaurs Troodon and Oviraptor that incubated their eggs. Irrespective of whether you accept the idea of Theropod dinosaurs sitting on eggs like birds or not, the analysis raised some concerns that we wanted to address. We decided to repeat the study with a larger data set and a better understanding of bird biology because other palaeontologists were starting to use the original results in Science in order to predict the incubation behaviour of other dinosaur species. Our analysis of the relationship between female body mass and clutch mass was interesting in its own right but also showed that it was not possible to conclude anything about incubation in extinct distant relatives of the birds.”
Palaeobiologist Dr Ruta was involved in mapping the parental behaviour in modern birds on to an evolutionary tree.
Dr Ruta said: “As always in any study involving fossils, knowledge of extant organisms helps us make inferences about fossils. Fossils have a unique role in shaping our knowledge of the Tree of Life and the dynamics of evolutionary processes. However, as is the case with our study, data from living organisms may augment and refine the potential of fossil studies and may shift existing notions of the biology and behaviour of long extinct creatures.”
Dr Birchard added: “The previous study was carried out to infer the type of parental care in dinosaurs that are closely related to birds. That study proposed that paternal care was present in these dinosaurs and this form of care was the ancestral condition for birds. Our new analysis based on three times as many species as in the previous study indicates that parental care cannot be inferred from simple analyses of the relationship of body size to shape, anatomy, physiologyand behaviour. Such analyses ought to take into account factors such as shared evolutionary history and maturity at hatching. However, our data does suggest that the dinosaurs used in the previous study were likely to be quite mature at birth.”
The project has helped in understanding the factors affecting the evolution of incubation in birds. More importantly it is hoped that the new analysis will assist palaeontologists in their interpretation of future finds of dinosaur reproduction in the fossil record.
Four New Dinosaur Species Identified
May 8, 2013 — Just when dinosaur researchers thought they had a thorough knowledge of ankylosaurs, a family of squat, armour plated, plant eaters, along comes University of Alberta graduate student, Victoria Arbour.
Arbour visited dinosaur fossil collections from Alberta to the U.K. examining skull armour and comparing those head details with other features of the fossilized ankylosaur remains. She made a breakthrough that resurrected research done more than 70 years ago.
Arbour explains that between 1900 and 1930 researchers had determined that small variations in the skull armour and the tail clubs in some ankylosaurs constituted four individual species of the dinosaurs.
“In the 1970s the earlier work was discarded and those four species were lumped into one called species Euoplocephalus,” said Arbour.
“I examined many fossils and found I could group some fossils together because their skull armour corresponded with a particular shape of their tail club,” said Arbour.
Finding common features in fossils that come from the same geologic time is evidence that the original researchers were right says Arbour. “There were in fact four different species represented by what scientists previously thought was only one species, Euoplocephalus.”
The four species span a period of about 10 million years. Arbour’s research shows three of those ankylosaurs species lived at the same time in what is now Dinosaur Provincial Park in southern Alberta.
Arbour says this opens the door to new questions.
“How did these three species shared their habitat, how did they divide food resources and manage to survive?” said Arbour.
Arbour will also look into how slight differences in skull ornamentation and tail shape between the species influenced the animals’ long reign on Earth.
Arbour’s research was published May 8, in the journal PLOS ONE.
Oldest? New ‘Bone-Head’ Dinosaur Hints at Higher Diversity of Small Dinosaurs
May 7, 2013 — Scientists have named a new species of bone-headed dinosaur (pachycephalosaur) from Alberta, Canada. Acrotholus audeti (Ack-RHO-tho-LUS) was identified from both recently discovered and historically collected fossils. Approximately six feet long and weighing about 40 kilograms in life, the newly identified plant-eating dinosaur represents the oldest bone-headed dinosaur in North America, and possibly the world.
Dr. Michael Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History, co-authored research describing the new species, which was published May 7, 2013 in the journal Nature Communications.
Acrotholus means “high dome,” referring to its dome-shaped skull, which is composed of solid bone over 10 centimeters (two inches) thick. The name Acrotholus audeti also honors Alberta rancher Roy Audet, on whose land the best specimen was discovered in 2008. Acrotholus walked on two legs and had a greatly thickened, domed skull above its eyes, which was used for display to other members of its species, and may have also been used in head-butting contests. Acrotholus lived about 85 million years ago.
The new dinosaur discovery is based on two skull ‘caps’ from the Milk River Formation of southern Alberta. One of these was collected by the Royal Ontario Museum (ROM) more than 50 years ago. However, a better specimen was found in 2008 by University of Toronto graduate student Caleb Brown during a field expedition organized by Dr. David Evans of the Royal Ontario Museum and University of Toronto, and Ryan.
“Acrotholus provides a wealth of new information on the evolution of bone-headed dinosaurs. Although it is one of the earliest known members this group, its thickened skull dome is surprisingly well-developed for its geological age,” said lead author Evans, ROM curator, vertebrate palaeontology. “More importantly, the unique fossil record of these animals suggests that we are only beginning to understand the diversity of small-bodied plant-eating dinosaurs.”
Small mammals and reptiles can be very diverse and abundant in modern ecosystems, but small dinosaurs (less than 100 kg) are considerably less common than large ones in the fossil record. Whether this pattern is a true reflection of dinosaur communities, or is related to the greater potential for small bones to be destroyed by carnivores and natural decay, has been debated. The massively constructed skull domes of pachycephalosaurs are resistant to destruction, and are much more common than their relatively delicate skeletons — which resemble those of other small plant-eating dinosaurs. Therefore, the researchers suggest that the pachycephalosaur fossil record can provide valuable insights into the diversity of small, plant-eating dinosaurs as a whole.
“We can predict that many new small dinosaur species like Acrotholus are waiting to be discovered by researchers willing to sort through the many small bones that they pick up in the field,” said co-author Ryan of The Cleveland Museum of Natural History. “This fully domed and mature individual suggests that there is an undiscovered, hidden diversity of small-bodied dinosaurs. So when we look back, we need to reimagine the paleoenvironment. There is an evolutionary history that we just don’t know because the fossil record is incomplete. This discovery also highlights the importance of landowners, like Roy Audet, who grant access to their land and allow scientifically important finds to be made.”
This dinosaur is the latest in a series of new finds being made by Evans and Ryan as part of their Southern Alberta Dinosaur Project, which aims to fill in gaps in of the record of Late Cretaceous dinosaurs and study their evolution. This project focuses on the palaeontology of some of the oldest dinosaur-bearing rocks in Alberta, which have been studied less intensely than those of the famous badlands of Dinosaur Provincial Park and Drumheller.
Acrotholus was identified by a team comprising of palaeontologists Evans, of the Royal Ontario Museum; and Ryan, of The Cleveland Museum of Natural History; as well as Ryan Schott, Caleb Brown, and Derek Larson, all graduate students at the University of Toronto who studied under Evans.
Bird Fossil Sheds Light On How Swift and Hummingbird Flight Came to Be
May 1, 2013 — A tiny bird fossil discovered in Wyoming offers clues to the precursors of swift and hummingbird wings. The fossil is unusual in having exceptionally well-preserved feathers, which allowed the researchers to reconstruct the size and shape of the bird’s wings in ways not possible with bones alone.
Researchers spotted the specimen — the nearly complete skeleton of a bird that would have fit in the palm of your hand and weighed less than an ounce — while working at the Field Museum of Natural History in Chicago.
The newly discovered bird was named Eocypselus rowei, in honor of John W. Rowe, Chairman of the Field Museum’s Board of Trustees.
First collected in southwestern Wyoming in a fossil site known as the Green River Formation, E. rowei lived roughly 50 million years ago, after the dinosaurs disappeared but before the earliest humans came to be.
E. rowei was a tiny bird — only twelve centimeters from head to tail. Feathers account for more than half of the bird’s total wing length.
To find out where the fossil fit in the bird family tree, the researchers compared the specimen to extinct and modern day species. Their analyses suggest that the bird was an evolutionary precursor to the group that includes today’s swifts and hummingbirds.
Given the differences in wing shape between these two closely related groups of birds, scientists have puzzled over how swift and hummingbird flight came to be. Finding fossil relatives like this specimen is key to figuring that out, the researchers say.
“This fossil bird represents the closest we’ve gotten to the point where swifts and hummingbirds went their separate ways,” said lead author Daniel Ksepka of the National Evolutionary Synthesis Center in Durham, North Carolina.
Hummingbirds have short wings relative to their bodies, which makes them good at hovering in mid-air. Swifts have super-long wings for gliding and high-speed flight. But the wings of E. rowei were somewhere in between.
“[Based on its wing shape] it probably wasn’t a hoverer, like a hummingbird, and it probably wasn’t as efficient at fast flight as a swift,” Ksepka said.
The shape of the bird’s wings, coupled with its tiny size, suggest that the ancestors of today’s swifts and hummingbirds got small before each group’s unique flight behavior came to be. “Hummingbirds came from small-bodied ancestors, but the ability to hover didn’t come to be until later,” Ksepka explained.
Closer study of the feathers under a scanning electron microscope revealed that carbon residues in the fossils — once thought to be traces of bacteria that fed on feathers — are fossilized melanosomes, tiny cell structures containing melanin pigments that give birds and other animals their color. The findings suggest that the ancient bird was probably black and may have had a glossy or iridescent sheen, like swifts living today. Based on its beak shape it probably ate insects, the researchers say.
The other authors of this study were Julia Clarke, Sterling Nesbitt and Felicia Kulp of the University of Texas at Austin, and Lance Grande of the Field Museum of Natural History.
The results will appear in the May 1 issue of the journal Proceedings of the Royal Society B.
What Happened to Dinosaurs’ Predecessors After Earth’s Largest Extinction 252 Million Years Ago?
Predecessors to dinosaurs missed the race to fill habitats emptied when nine out of 10 species disappeared during Earth’s largest mass extinction 252 million years ago.
Or did they?
That thinking was based on fossil records from sites in South Africa and southwest Russia.
It turns out, however, that scientists may have been looking in the wrong places.
Newly discovered fossils from 10 million years after the mass extinction reveal a lineage of animals thought to have led to dinosaurs in Tanzania and Zambia.
That’s still millions of years before dinosaur relatives were seen in the fossil record elsewhere on Earth.
“The fossil record from the Karoo of South Africa, for example, is a good representation of four-legged land animals across southern Pangea before the extinction,” says Christian Sidor, a paleontologist at the University of Washington.
Pangea was a landmass in which all the world’s continents were once joined together. Southern Pangea was made up of what is today Africa, South America, Antarctica, Australia and India.
“After the extinction,” says Sidor, “animals weren’t as uniformly and widely distributed as before. We had to go looking in some fairly unorthodox places.”
Sidor is the lead author of a paper reporting the findings; it appears in this week’s issue of the journal Proceedings of the National Academy of Sciences.
The insights come from seven fossil-hunting expeditions in Tanzania, Zambia and Antarctica funded by the National Science Foundation (NSF). Additional work involved combing through existing fossil collections.
“These scientists have identified an outcome of mass extinctions–that species ecologically marginalized before the extinction may be ‘freed up’ to experience evolutionary bursts then dominate after the extinction,” says H. Richard Lane, program director in NSF’s Division of Earth Sciences.
The researchers created two “snapshots” of four-legged animals about five million years before, and again about 10 million years after, the extinction 252 million years ago.
Prior to the extinction, for example, the pig-sized Dicynodon–said to resemble a fat lizard with a short tail and turtle’s head–was a dominant plant-eating species across southern Pangea.
After the mass extinction, Dicynodon disappeared. Related species were so greatly decreased in number that newly emerging herbivores could then compete with them.
“Groups that did well before the extinction didn’t necessarily do well afterward,” Sidor says.
The snapshot of life 10 million years after the extinction reveals that, among other things, archosaurs roamed in Tanzanian and Zambian basins, but weren’t distributed across southern Pangea as had been the pattern for four-legged animals before the extinction.
Archosaurs, whose living relatives are birds and crocodilians, are of interest to scientists because it’s thought that they led to animals like Asilisaurus, a dinosaur-like animal, and Nyasasaurus parringtoni, a dog-sized creature with a five-foot-long tail that could be the earliest dinosaur.
“Early archosaurs being found mainly in Tanzania is an example of how fragmented animal communities became after the extinction,” Sidor says.
A new framework for analyzing biogeographic patterns from species distributions, developed by paper co-author Daril Vilhena of University of Washington, provided a way to discern the complex recovery.
It revealed that before the extinction, 35 percent of four-legged species were found in two or more of the five areas studied.
Some species’ ranges stretched 1,600 miles (2,600 kilometers), encompassing the Tanzanian and South African basins.
Ten million years after the extinction, there was clear geographic clustering. Just seven percent of species were found in two or more regions.
The technique–a new way to statistically consider how connected or isolated species are from each other–could be useful to other paleontologists and to modern-day biogeographers, Sidor says.
Beginning in the early 2000s, he and his co-authors conducted expeditions to collect fossils from sites in Tanzania that hadn’t been visited since the 1960s, and in Zambia where there had been little work since the 1980s.
Two expeditions to Antarctica provided additional finds, as did efforts to look at museum fossils that had not been fully documented or named.
The fossils turned out to hold a treasure trove of information, the scientists say, on life some 250 million years ago.
Other co-authors of the paper are Adam Huttenlocker, Brandon Peecook, Sterling Nesbitt and Linda Tsuji from University of Washington; Kenneth Angielczyk of the Field Museum of Natural History in Chicago; Roger Smith of the Iziko South African Museum in Cape Town; and Sébastien Steyer from the National Museum of Natural History in Paris.
The project was also funded by the National Geographic Society, Evolving Earth Foundation, the Grainger Foundation, the Field Museum/IDP Inc. African Partners Program, and the National Research Council of South Africa.
Fish Was On the Menu for Early Flying Dinosaur
Apr. 22, 2013 — University of Alberta-led research reveals that Microraptor, a small flying dinosaur was a complete hunter, able to swoop down and pickup fish as well as its previously known prey of birds and tree dwelling mammals.
U of A paleontology graduate student Scott Persons says new evidence of Microrpator’s hunting ability came from fossilized remains in China. “We were very fortunate that this Microraptor was found in volcanic ash and its stomach content of fish was easily identified.”
Prior to this, paleontologists believed microraptors which were about the size of a modern day hawk, lived in trees where they preyed exclusively on small birds and mammals about the size of squirrels.
“Now we know that Microraptor operated in varied terrain and had a varied diet,” said Persons. “It took advantage of a variety of prey in the wet, forested environment that was China during the early Cretaceous period, 120 million years ago.”
Further analysis of the fossil revealed that its teeth were adapted to catching slippery, wiggling prey like fish. Dinosaur researchers have established that most meat eaters had teeth with serrations on both sides which like a steak knife helped the predator saw through meat.
But the Microraptor’s teeth are serrated on just one side and its teeth are angled forwards.
“Microraptor seems adapted to impale fish on its teeth. With reduced serrations the prey wouldn’t tear itself apart while it struggled,” said Persons. “Microraptor could simply raise its head back, the fish would slip off the teeth and be swallowed whole, no fuss no muss.”
Persons likens the Microraptor’s wing configuration to a bi-plane. “It had long feathers on its forearms, hind legs and tail,” said Persons. “It was capable of short, controlled flights.”
This is the first evidence of a flying raptor, a member of the Dromaeosaur family of dinosaurs to successfully prey on fish.
Dinosaur Egg Study Supports Evolutionary Link Between Birds and Dinosaurs: How Troodon Likely Hatched Its Young
A small, bird-like North American dinosaur incubated its eggs in a similar way to brooding birds — bolstering the evolutionary link between birds and dinosaurs, researchers at the University of Calgary and Montana State University study have found.
Among the many mysteries paleontologists have tried to uncover is how dinosaurs hatched their young. Was it in eggs completely buried in nest materials, like crocodiles? Or was it in eggs in open or non-covered nests, like brooding birds?
Using egg clutches found in Alberta and Montana, researchers Darla Zelenitsky at the University of Calgary and David Varricchio at Montana State University closely examined the shells of fossil eggs from a small meat-eating dinosaur called Troodon.
In a finding published in the spring issue of Paleobiology, they concluded that this specific dinosaur species, which was known to lay its eggs almost vertically, would have only buried the egg bottoms in mud.
“Based on our calculations, the eggshells of Troodon were very similar to those of brooding birds, which tells us that this dinosaur did not completely bury its eggs in nesting materials like crocodiles do,” says study co-author Zelenitsky, assistant professor of geoscience.
“Both the eggs and the surrounding sediments indicate only partial burial; thus an adult would have directly contacted the exposed parts of the eggs during incubation,” says lead author Varricchio, associate professor of paleontology.
Varricchio says while the nesting style for Troodon is unusual, “there are similarities with a peculiar nester among birds called the Egyptian Plover that broods its eggs while they’re partially buried in sandy substrate of the nest.”
Paleontologists have always struggled to answer the question of how dinosaurs incubated their eggs, because of the scarcity of evidence for incubation behaviours.
As dinosaurs’ closest living relatives, crocodiles and birds offer some insights.
Scientists know that crocodiles and birds that completely bury their eggs for hatching have eggs with many pores or holes in the eggshell, to allow for respiration.
This is unlike brooding birds which don’t bury their eggs; consequently, their eggs have far fewer pores.
The researchers counted and measured the pores in the shells of Troodon eggs to assess how water vapour would have been conducted through the shell compared with eggs from contemporary crocodiles, mound-nesting birds and brooding birds.
They are optimistic their methods can be applied to other dinosaur species’ fossil eggs to show how they may have been incubated.
“For now, this particular study helps substantiate that some bird-like nesting behaviors evolved in meat-eating dinosaurs prior to the origin of birds. It also adds to the growing body of evidence that shows a close evolutionary relationship between birds and dinosaurs,” Zelenitsky says.
New Carnivorous Dinosaur from Madagascar Raises More Questions Than It Answers
The first new species of dinosaur from Madagascar in nearly a decade was announced today, filling an important gap in the island’s fossil record.
Dahalokely tokana (pronounced “dah-HAH-loo-KAY-lee too-KAH-nah”) is estimated to have been between nine and 14 feet long, and it lived around 90 million years ago. Dahalokely belongs to a group called abelisauroids, carnivorous dinosaurs common to the southern continents. Up to this point, no dinosaur remains from between 165 and 70 million years ago could be identified to the species level in Madagascar-a 95 million year gap in the fossil record. Dahalokely shortens this gap by 20 million years.
The fossils of Dahalokely were excavated in 2007 and 2010, near the city of Antsiranana (Diego-Suarez) in northernmost Madagascar. Bones recovered included vertebrae and ribs. Because this area of the skeleton is so distinct in some dinosaurs, the research team was able to definitively identify the specimen as a new species. Several unique features — including the shape of some cavities on the side of the vertebrae — were unlike those in any other dinosaur. Other features in the vertebrae identified Dahalokely as an abelisauroid dinosaur.
When Dahalokely was alive, Madagascar was connected to India, and the two landmasses were isolated in the middle of the Indian Ocean. Geological evidence indicates that India and Madagascar separated around 88 million years ago, just after Dahalokely lived. Thus, Dahalokely potentially could have been ancestral to animals that lived later in both Madagascar and India. However, not quite enough of Dahalokely is yet known to resolve this issue. The bones known so far preserve an intriguing mix of features found in dinosaurs from both Madagascar and India.
“We had always suspected that abelisauroids were in Madagascar 90 million years ago, because they were also found in younger rocks on the island. Dahalokely nicely confirms this hypothesis,” said project leader Andrew Farke, Augustyn Family Curator of Paleontology at the Raymond M. Alf Museum of Paleontology. Farke continued, “But, the fossils of Dahalokely are tantalizingly incomplete — there is so much more we want to know. Was Dahalokely closely related to later abelisauroids on Madagascar, or did it die out without descendents?”
The name “Dahalokely tokana” is from the Malagasy language, meaning “lonely small bandit.” This refers to the presumed carnivorous diet of the animal, as well as to the fact that it lived at a time when the landmasses of India and Madagascar together were isolated from the rest of the world.
“This dinosaur was closely related to other famous dinosaurs from the southern continents, like the horned Carnotaurus from Argentina and Majungasaurus, also from Madagascar,” said project member Joe Sertich, Curator of Dinosaurs at the Denver Museum of Nature & Science and the team member who discovered the new dinosaur. “This just reinforces the importance of exploring new areas around the world where undiscovered dinosaur species are still waiting,” added Sertich.
The research was funded by the Jurassic Foundation, Sigma Xi, National Science Foundation, and the Raymond M. Alf Museum of Paleontology. The paper naming Dahalokely appears in the April 18, 2013, release of the journal PLOS ONE.
Strange Spaghetti-Shaped Creature Is Missing Link: Discovery Pushes Fossil Record Back 200 Million Years
Mar. 13, 2013 — Canada’s 505 million year-old Burgess Shale fossil beds, located in Yoho National Park, have yielded yet another major scientific discovery — this time with the unearthing of a strange spaghetti-shaped creature.
It’s a discovery that pushes back the fossil record of a group of creatures known as enteropneusts by 200 million years — and provides the crucial “missing link” in an important evolutionary transformation.
“Unlike animals with teeth and bones, these spaghetti-shaped creatures were soft-bodied, so the fossil record for them is extremely scarce,” said Jean-Bernard Caron, associate professor of Earth Sciences and Ecology & Evolutionary Biology at the University of Toronto and curator of invertebrate palaeontology at the Royal Ontario Museum.
“Our analysis of Spartobranchus tenuis, a creature previously unknown to science, pushes the fossil record of the enteropneusts back by 200 million years and illuminates our understanding of the early evolution of this group of organisms,” Caron said.
Caron is the lead author of the study published online in the journal Nature March 13 2013 which found Spartobranchus tenuis is a member of the acorn worms group. Acorn worms are marine animals that belong to the phylum hemichordates, a group which is closely related to todays sea stars and sea urchins. While Spartobranchus tenuis is long extinct, other species of acorn worms thrive in the fine sands and mud of deep and shallow waters in present-day ecosystems.
Since the discovery of hemichordates in the 19th century, some of the biggest questions in hemichordate evolution have focused on the group’s origins and the relationship between its two main branches: the enteropneusts and pterobranchs. Enteropneusts and pterobranchs look very different, yet share many genetic and developmental characteristics that reveal an otherwise unexpected close relationship.
“Spartobranchus tenuis represents a crucial missing link that serves not only to connect the two main hemichordate groups but helps to explain how an important evolutionary transformation was achieved,” said Caron. “Our study suggests that primitive enteropneusts developed a tubular structure — the smoking gun — which has been retained over time in modern pterobranchs.”
Hemichordates also share many of the same characteristics as chordates — a group of animals that includes humans — with the name hemichordate roughly translating to ‘half a chordate.’
Spartobranchus tenuis probably fed on small particles of matter at the bottom of the oceans.
“There are literally thousands of specimens at the Walcott Quarry in Yoho National Park, so it’s possible Spartobranchus tenuis may have played an important role in recycling organic matter in the early Burgess Shale environment, similar to the ecological service provided by earth worms today on land,” said Caron.
Detailed analysis suggests Spartobranchus tenuis (illustration at right by Marianne Collins) had a flexible body consisting of a short proboscis, collar and narrow elongate trunk terminating in a bulbous structure, which may have served as an anchor.
The largest complete specimens examined were 10 centimetres long with the proboscis accounting for about half a centimetre. A large proportion of these worms was preserved in tubes, of which some were branched, suggesting the tubes were used as a dwelling structure.
Other members of the Spartobranchus tenuis research team are Simon Conway Morris of the University of Cambridge and Christopher B. Cameron of the Université de Montréal. Last year Conway Morris and Caron published a well-publicized study on Pikaia, believed to be one of the planet’s first human relatives.
The Burgess Shale is found in Yoho National Park, part of the Canadian Rocky Mountain Parks World Heritage Site, and is one of the most important fossil deposits for understanding the origin and early evolution of animals that took place during the Cambrian Explosion starting about 542 million years ago.
Remains of Extinct Giant Camel Discovered in High Arctic
Mar. 5, 2013 — A research team led by the Canadian Museum of Nature has identified the first evidence for an extinct giant camel in Canada’s High Arctic. The discovery is based on 30 fossil fragments of a leg bone found on Ellesmere Island, Nunavut and represents the most northerly record for early camels, whose ancestors are known to have originated in North America some 45 million years ago.
The fossils were collected over three summer field seasons (2006, 2008 and 2010) and are about three-and-a-half million years old, dating from the mid-Pliocene Epoch. Other fossil finds at the site suggest this High Arctic camel lived in a boreal-type forest environment, during a global warm phase on the planet.
The research by Dr. Natalia Rybczynski and co-authors including Dr. John Gosse at Dalhousie University, Halifax and Dr. Mike Buckley at the University of Manchester, England is described in the March 5, 2013 edition of the online journal Nature Communications.
“This is an important discovery because it provides the first evidence of camels living in the High Arctic region,” explains Rybczynski, a vertebrate paleontologist with the Canadian Museum of Nature, who has led numerous field expeditions in Canada’s Arctic. “It extends the previous range of camels in North America northward by about 1,200 km, and suggests that the lineage that gave rise to modern camels may been originally adapted to living in an Arctic forest environment.”
The camel bones were collected from a steep slope at the Fyles Leaf Bed site, a sandy deposit near Strathcona Fiord on Ellesmere Island. Fossils of leaves, wood and other plant material have been found at this site, but the camel is the first mammal recovered. A nearby fossil-rich locality at Strathcona Fiord, known as the Beaver Pond site, has previously yielded fossils of other mammals from the same time period, including a badger, deerlet, beaver and three-toed horse.
Determining that the bones were from a camel was a challenge. “The first time I picked up a piece, I thought that it might be wood. It was only back at the field camp that I was able to ascertain it was not only bone, but also from a fossil mammal larger than anything we had seen so far from the deposits,” explains Rybczynski, relating the moment that she and her team had discovered something unusual.
Some important physical characteristics suggested the fossil fragments were part of a large tibia, the main lower-leg bone in mammals, and that they belonged to the group of cloven-hoofed animals known as arteriodactyls, which includes cows, pigs and camels. Digital files of each of the 30 bone fragments were produced using a 3D laser scanner, allowing for the pieces to be assembled and aligned. The size of the reconstituted leg bone suggested it was from a very large mammal. At the time in North America, the largest arteriodactyls were camels.
Full confirmation that the bones belonged to a camel came from a new technique called “collagen fingerprinting” pioneered by Dr. Mike Buckley at the University of Manchester in England. Profiles produced by this technique can be used to distinguish between groups of mammals.
Minute amounts of collagen, the dominant protein found in bone, were extracted from the fossils. Using chemical markers for the peptides that make up the collagen, a collagen profile for the fossil bones was developed. This profile was compared with those of 37 modern mammal species, as well as that of a fossil camel found in the Yukon, which is also in the Canadian Museum of Nature’s collections.
The collagen profile for the High Arctic camel most closely matched those of modern camels, specifically dromedaries (camels with one hump) as well as the Yukon giant camel, which is thought to be Paracamelus, the ancestor of modern camels. The collagen information, combined with the anatomical data, allowed Rybczynski and her colleagues to conclude that the Ellesmere bones belong to a camel, and is likely the same lineage as Paracamelus.
“We now have a new fossil record to better understand camel evolution, since our research shows that the Paracamelus lineage inhabitated northern North America for millions of years, and the simplest explanation for this pattern would be that Paracamelus originated there,” explains Rybczynski. “So perhaps some specializations seen in modern camels, such as their wide flat feet, large eyes and humps for fat may be adaptations derived from living in a polar environment.”
The scientific paper also reports for the first time an accurate age of both the Fyles Leaf Bed site and the Beaver Pond site — at least 3.4 million years old. This was determined by Dr. John Gosse at Dalhousie University using a sophisticated technique that involves dating the sands found associated with the bone. The date is significant because it corresponds to a time period when Earth was 2ºC à 3ºC warmer than today, and the Arctic was 14ºC à 22ºC warmer. The bones of the High Arctic camel are housed in the Canadian Museum of Nature’s research and collections facility in Gatineau, Quebec on behalf of the Government of Nunavut.