Features of Southeast European Human Ancestors Influenced by Lack of Episodic Glaciations
Feb. 6, 2013 — A fragment of human lower jaw recovered from a Serbian cave is the oldest human ancestor found in this part of Europe, who probably evolved under different conditions than populations that inhabited more western parts of the continent at the same time, according to research published Feb. 6 in the open access journal PLOS ONE.
The research was carried out by William Jack Rink of McMaster University, Canada, and the international team under the direction of Dušan Mihailović, University of Belgrade, Serbia, and Mirjana Roksandic, University of Winnipeg, Canada.
The fossil was found to be at least 397,000 years old and possibly older than 525,000 years old, a time when distinctly Neandertal traits began to appear in Europe. The evolution of these traits was strongly influenced by periodic isolation of groups of individuals, caused by episodic formation of glaciers. Humans in southeastern Europe were never geographically isolated from Asia and Africa by glaciers, and according to the authors, this resulted in different evolutionary forces acting on early human populations in this region.
Roksandic explains that their study confirms the importance of southeast Europe as a ‘gate to the continent’ and one of the three main areas where humans, plants and animals sought refuge during glaciations in prehistoric times. She adds, “We have very few fossils of hominins in general from this time, a period that was critical for shaping the appearance and evolution of uniquely human morphology and behaviors.”
Previous Unknown Fossilized Fox Species Found
Jan. 23, 2013 — Researchers from Wits University, the University of Johannesburg and international scientists have announced the discovery of a 2-million-year-old fossil fox at Malapa, South Africa, in the Cradle of Humankind World Heritage Site.
In an article published in the journal Transactions of the Royal Society of South Africa, the researchers describe the previously unknown species of fox named Vulpes Skinneri — named in honour of the recently deceased world renowned South African mammalogist and ecologist, Prof. John Skinner of the University of Pretoria.
The site of Malapa has, since its discovery in 2008, yielded one of the most extraordinary fossil assemblages in the African record, including skeletons of a new species of human ancestor named Australopithecus sediba, first described in 2010.
The new fox fossils consist of a mandible and parts of the skeleton and can be distinguished from any living or extinct form of fox known to science based on proportions of its teeth and other aspects of its anatomy.
Dr. Brian Kuhn of Wits’ Institute for Human Evolution (IHE) and the School of GeoSciences, an author on the paper and head of the Malapa carnivore studies explains: “It’s exciting to see a new fossil fox. The ancestry of foxes is perhaps the most poorly known among African carnivores and to see a potential ancestral form of living foxes is wonderful.”
Prof. Lee Berger, also of the IHE and School of GeoSciences, author on the paper and Director of the Malapa project notes: “Malapa continues to reveal this extraordinary record of past life and as important as the human ancestors are from the site, the site’s contribution to our understanding of the evolution of modern African mammals through wonderful specimens like this fox is of equal import. Who knows what we will find next?.”
The entire team has expressed their privilege in naming the new species after “John Skinner, one of the great names in the study of African mammals and particularly carnivores. We (the authors) think that John would be pleased, and it is fitting that this rare little find would carry his name forever.”
A Relative from the Tianyuan Cave: Humans Living 40,000 Years Ago Likely Related to Many Present-Day Asians and Native Americans
Jan. 21, 2013 — Ancient DNA has revealed that humans living some 40,000 years ago in the area near Beijing were likely related to many present-day Asians and Native Americans.
An international team of researchers including Svante Pääbo and Qiaomei Fu of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced nuclear and mitochondrial DNA that had been extracted from the leg of an early modern human from Tianyuan Cave near Beijing, China. Analyses of this individual’s DNA showed that the Tianyuan human shared a common origin with the ancestors of many present-day Asians and Native Americans. In addition, the researchers found that the proportion of Neanderthal and Denisovan-DNA in this early modern human is not higher than in people living in this region nowadays.
Humans with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 years ago. The genetic relationships between these early modern humans and present-day human populations had not yet been established. Qiaomei Fu, Matthias Meyer and colleagues of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, extracted nuclear and mitochondrial DNA from a 40,000 year old leg bone found in 2003 at the Tianyuan Cave site located outside Beijing. For their study the researchers were using new techniques that can identify ancient genetic material from an archaeological find even when large quantities of DNA from soil bacteria are present.
The researchers then reconstructed a genetic profile of the leg’s owner. “This individual lived during an important evolutionary transition when early modern humans, who shared certain features with earlier forms such as Neanderthals, were replacing Neanderthals and Denisovans, who later became extinct,” says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology, who led the study.
The genetic profile reveals that this early modern human was related to the ancestors of many present-day Asians and Native Americans but had already diverged genetically from the ancestors of present-day Europeans. In addition, the Tianyuan individual did not carry a larger proportion of Neanderthal or Denisovan DNA than present-day people in the region. “More analyses of additional early modern humans across Eurasia will further refine our understanding of when and how modern humans spread across Europe and Asia,” says Svante Pääbo.
Parts of the work were carried out in a new laboratory jointly run by the Max Planck Society and the Chinese Academy of Sciences in Beijing.
Earliest Sea Cow Ancestors Originated in Africa, Lived in Fresh Water
Jan. 16, 2013 — A new fossil discovered in Tunisia represents the oldest known ancestor of modern-day sea cows, supporting the African origins of these marine mammals. The find is described in research published January 16 in the open access journal PLOS ONE by Julien Benoit and colleagues from the University of Science and Technology in Montpellier, France.
Some fossils of sea cow ancestors have been found in Jamaica, but the Tunisian fossil is more primitive and pre-dates these, revealing an older ancestor for sea cows that emerged at the same time as other modern mammals. Unlike whales and dolphins, the evolutionary origins of the sea cow family have been obscure.
They share an ancestor with elephants, and it is thought that their oldest relatives were terrestrial animals that gradually adapted to an aquatic life. The last common ancestor of the two species may have lived in freshwater swamps well before the time that the new species described in this study lived.
Though this specimen may not have been the common link between modern day sea cows and elephants, the authors’ analyses suggest that this new species lived in fresh water, not sea waters.
New Study Sheds Light On Dinosaur Size
Dec. 19, 2012 — Dinosaurs were not only the largest animals to roam the Earth — they also had a greater number of larger species compared to all other back-boned animals — scientists suggest in a new paper published in the journal PLOS ONE.
The researchers, from Queen Mary, University of London, compared the size of the femur bone of 329 different dinosaur species from fossil records. The length and weight of the femur bone is a recognised method in palaeontology for estimating a dinosaur’s body mass.
They found that dinosaurs follow the opposite pattern of body size distribution as seen in other vertebrate species. For example, within living mammals there tends to be few larger species, such as elephants, compared to smaller animals, such as mice, which have many species. The evidence from fossil records implies that in contrast there were many species of larger dinosaurs and few small species.
Dr David Hone from Queen Mary’s School of Biological and Chemical Sciences, explains: “What is remarkable is that this tendency to have more species at a bigger size seemed to evolve quite early on in dinosaurian evolution around the Late Triassic period, 225 million years ago, raising questions about why they got to be so big.
“Our evidence supports the hypothesis that young dinosaurs occupied a different ecological niche to their parents so they weren’t in competition for the same sources of food as they ate smaller plants or preyed on smaller size animals. In fact, we see modern crocodiles following this pattern — baby crocodiles start by feeding off insects and tadpoles before graduating onto fish and then larger mammals.”
Dr Eoin Gorman, also from Queen Mary’s School of Biological and Chemical Sciences added: “There is growing evidence that dinosaurs produced a large number of offspring, which were immediately vulnerable to predation due to their smaller size. It was beneficial for the herbivores to grow to large size as rapidly as possible to escape this threat, but the carnivores had sufficient resources to live optimally at smaller sizes.
“These differences are reflected in our analyses and also offer an explanation why other groups do not follow a similar pattern. Several modern-day vertebrate groups are almost entirely carnivorous, while many of the herbivores are warm-blooded, which limits their size.”
New Dinosaur: First Freshwater Mosasaur Discovered
Dec. 19, 2012 — A new mosasaur species discovered in Hungary is the first known example of this group of scaled reptiles to have lived in freshwater river environments similar to modern freshwater dolphins.
The research is published Dec. 19 in the open-access journal PLOS ONE by Laszlo Makadi from the Hungarian Natural History Museum, Hungary and colleagues from the University of Alberta, Canada and MTA-ELTE Lendület Dinosaur Research Group, Hungary.
The species lived about 84 million years ago, the largest specimens reached about 20 feet in length, and belongs to a family called ‘mosasaurs’, conventionally thought of as gigantic finned marine lizards, similar and perhaps even related to present day monitor lizards. The researchers discovered several fossils of the new species, ranging from small juveniles to large adults that suggest that this species had limbs like a terrestrial lizard, a flattened, crocodile-like skull, and a tail unlike other known members of the mosasaur family.
The fossils were recovered from an open-pit mine in the Bakony Hills of Western Hungary, which were once flood-plains. According to the study, this is the first known mosasaur that lived in freshwater, and only the second specimen of a mosasaur to have been found in rocks that were not once deposited in the ocean. Makadi says, “The evidence we provide here makes it clear that similar to some lineages of cetaceans, mosasaurs quickly adapted to a variety of aquatic environments, with some groups re- invading available niches in freshwater habitats. The size of Pannoniasaurus makes it the largest known predator in the waters of this paleo-environment.”
Even in the modern world, scaly reptiles in the aquatic world are extremely rare. Only a few species live in the water, and even fewer, like marine iguanas and sea kraits, live in the oceans. The new species described here probably adapted to freshwater environments similarly to river dolphins, such as those now inhabiting the Amazon, Ganges and Yangtze rivers.
Evidence Contradicts Idea That Starvation Caused Saber-Tooth Cat Extinction
Dec. 26, 2012 — In the period just before they went extinct, the American lions and saber-toothed cats that roamed North America in the late Pleistocene were living well off the fat of the land.
That is the conclusion of the latest study of the microscopic wear patterns on the teeth of these great cats recovered from the La Brea tar pits in southern California. Contrary to previous studies, the analysis did not find any indications that the giant carnivores were having increased trouble finding prey in the period before they went extinct 12,000 years ago.
The results, published on Dec. 26 in the scientific journal PLOS ONE, contradicts previous dental studies and presents a problem for the most popular explanations for the Megafaunal (or Quaternary) extinction when the great cats, mammoths and a number of the largest mammals that existed around the world disappeared.
“The popular theory for the Megafaunal extinction is that either the changing climate at the end of the last Ice Age or human activity — or some combination of the two — killed off most of the large mammals,” said Larisa DeSantis, assistant professor of earth and environmental sciences at Vanderbilt, who headed the study. “In the case of the great cats, we expect that it would have been increasingly difficult for them to find prey, especially if had to compete with humans. We know that when food becomes scarce, carnivores like the great cats tend to consume more of the carcasses they kill. If they spent more time chomping on bones, it should cause detectable changes in the wear patterns on their teeth.”
In 1993, Blaire Van Valkenburgh at UCLA published a paper on tooth breakage in large carnivores in the late Pleistocene. Analyzing teeth of American lions, saber-tooth cats, dire wolves and coyotes from La Brea, she found that they had approximately three times the number of broken teeth of contemporary predators and concluded, .” ..these findings suggest that these species utilized carcasses more fully and likely competed more intensely for food than present-day large carnivores.”
The latest study uses a new technique, called dental microwear texture analysis (DMTA), developed by co-author Peter Ungar at the University of Arkansas. It uses a confocal microscope to produce a three-dimensional image of the surface of a tooth. The image is then analyzed for microscopic wear patterns. Chowing down on red meat produces small parallel scratches. Chomping on bones adds larger, deeper pits. Previous methods of dental wear analysis relied on researchers to identify and count these different types of features. DMTA relies on automated software and is considered more accurate because it reduces the possibility of observer bias.
DeSantis and Ungar, with the assistance of Blaine Schubert from East Tennessee State University and Jessica Scott from the University of Arkansas, applied DMTA to the fossil teeth of 15 American lions (Panthera atrox) and 15 saber-tooth cats (Smilodon fatalis) recovered from the La Brea tar pits in Los Angeles.
Their analysis revealed that the wear pattern on the teeth of the American lion most closely resembled those of the present-day cheetah, which actively avoids bones when it feeds. Similarly, the saber-tooth cat’s wear pattern most closely resembled those of the present-day African lion, which indulges in some bone crushing when it eats. (This differs from a previous microwear study using a different technique that concluded saber-tooth cats avoided bone to a far greater extent.)
The researchers examined how these patterns changed over time by selecting specimens from tar pits of different ages, ranging from about 35,000 to 11,500 years ago. They did not find any evidence that the two carnivores increased their “utilization” of carcasses throughout this period. If anything, their analysis suggests that the proportion of the carcasses that both kinds of cats consumed actually declined toward the end.
The researchers acknowledge the high rate of tooth breakage reported in the previous study, but they argue that it is more likely the result of increased breakage when taking down prey instead of when feeding.
“Teeth can break from the stress of chewing bone but they can also break when the carnivores take down prey,” DeSantis pointed out. Species like hyenas that regularly chew and crack bones of their kills are as likely to break the rear teeth they use for chewing as their front canines. Species like the cheetah, however, which avoid bones during feeding are twice as likely to break canines than rear teeth. This suggests that they are more likely to break canines when pulling down prey.
The researchers report that previous examinations of the jaws of the American lions and saber-tooth cats from this period found that they have more than three times as many broken canines and interpret this as additional evidence that supports their conclusion that most of the excess tooth breakage occurred during capture instead of feeding.
In addition, the researchers argue that the large size of the extinct carnivores and their prey can help explain the large number of broken teeth. The saber-toothed cats were about the size of today’s African lion and the American lion was about 25 percent larger. The animals that they preyed upon likely included mammoths, four-ton giant ground sloths and 3,500-pound bison.
Larger teeth break more easily than smaller teeth. So larger carnivores are likely to break more canine teeth when attempting to take down larger prey, the researchers argue. They cite a study that modeled the strength of canine teeth that found the canines of a predator the size of fox can support more than seven times its weight before breaking while a predator the size of lion can only support about four times its weight and the curved teeth of the saber-toothed cats can only support about twice its weight.
“The net result of our study is to raise questions about the reigning hypothesis that “tough times” during the late Pleistocene contributed to the gradual extinction of large carnivores,” DeSantis summarized. “While we can not determine the exact cause of their demise, it is unlikely that the extinction of these cats was a result of gradually declining prey (due either to changing climates or human competition) because their teeth tell us that these cats were not desperately consuming entire carcasses, as we had expected, and instead seemed to be living the ‘good life’ during the late Pleistocene, at least up until the very end.”
Rare Fossil Related to Crabs, Lobsters, Shrimp: Exceptionally Well Preserved, Including Shell and Soft Parts
Dec. 12, 2012 — An international team of researchers have made an extremely rare discovery of a species of animal — related to crabs, lobsters and shrimps — that is new to science.
Scientists from the universities of Leicester, Oxford, Imperial and Yale have announced their discovery of a new and scientifically important fossil species of ostracod in the journal Proceedings of The Royal Society B. The research was funded by the Natural Environment Research Council.
The discovered species, which is up to 10 millimetres long, is special because it is exceptionally well preserved, complete with not only the shell but also the soft parts — its body, limbs, eyes, gills and alimentary system. Such discoveries are extremely rare in the fossil record.
The discovery of the tiny shelled arthropod was made in 425 million year old rocks in Herefordshire, Welsh Borderland. The rocks at the site date to the Silurian period of geological time, when southern Britain was a sea area on a small continent situated in warm, southerly subtropical latitudes. The ostracods and associated marine animals living there were covered by a fall of volcanic ash that preserved them frozen in time.
Professor David Siveter, of the University of Leicester Department of Geology, said: “The two ostracod specimens discovered represent a genus and species new to science, named Pauline avibella. The genus is named in honour of a special person and avibella means ‘beautiful bird’, so-named because of the fancied resemblance of a prominent feature of the shell to the wing of a bird.”
“Ostracods are the most abundant fossil arthropods, occurring ubiquitously as bivalved shells in rocks of the last 490 million years, and are common in most water environments today. The find is important because it is one of only a handful preserving the fossilised soft-tissues of ostracods. Its assignment to a particular group of ostracods based on knowledge of its biology is at odds with its shell form, thus urging caution in interpreting the classification of fossil ostracods based on shell characters alone.”
“The preservation of soft-parts of animals is a very rare occurrence in the fossil record and allows unparalleled insight into the ancient biology, community structure and evolution of animals — key facts that that would otherwise be lost to science. The fossils known from the Herefordshire site show soft-part preservation and are of global importance.”
The fossils were reconstructed ‘virtually’, by using a technique that involves grinding each specimen down, layer by layer, and photographing it at each stage. Ten millimetres is relatively tiny, but at an incremental level of 20 µm (micrometres) that yields 500 slices, which can then be pieced together in a computer to provide a full, three-dimensional image of each fossil, outside and in.
Professor Siveter added: “Fossil discoveries in general help elucidate our own place in the tree of life. This discovery adds another piece of knowledge in the jigsaw of understanding the diversity and evolution of animals.”
“It is exciting to discover that a common group of fossils that we thought we knew a lot about may well have been hood-winking us as to their true identity, which we now realise because we have their beautifully fossilised soft-parts. A case of a ‘wolf in sheep’s clothing’.”
The research was undertaken together with Professor Derek Siveter and Dr Sarah Joomun (Oxford), Dr Mark Sutton (Imperial College London) and Professor Derek Briggs (Yale, USA).
Note: The genus is named in honour of Pauline Siveter, in memoriam, late wife of the lead author of the paper.
Asteroid That Killed the Dinosaurs Also Wiped out the ‘Obamadon’
Dec. 10, 2012 — The asteroid collision widely thought to have killed the dinosaurs also led to extreme devastation among snake and lizard species, according to new research — including the extinction of a newly identified lizard Yale and Harvard scientists have named Obamadon gracilis.
“The asteroid event is typically thought of as affecting the dinosaurs primarily,” said Nicholas R. Longrich, a postdoctoral associate with Yale’s Department of Geology and Geophysics and lead author of the study. “But it basically cut this broad swath across the entire ecosystem, taking out everything. Snakes and lizards were hit extremely hard.”
The study was scheduled for online publication the week of Dec. 10 in the Proceedings of the National Academy of Sciences.
Earlier studies have suggested that some snake and lizard species (as well as many mammals, birds, insects and plants) became extinct after the asteroid struck Earth 65.5 million years ago, on the edge of the Yucatan Peninsula. But the new research argues that the collision’s consequences were far more serious for snakes and lizards than previously understood. As many as 83 percent of all snake and lizard species died off, the researchers said — and the bigger the creature, the more likely it was to become extinct, with no species larger than one pound surviving.
The results are based on a detailed examination of previously collected snake and lizard fossils covering a territory in western North America stretching from New Mexico in the southwestern United States to Alberta, Canada. The authors examined 21 previously known species and also identified nine new lizards and snakes.
They found that a remarkable range of reptile species lived in the last days of the dinosaurs. Some were tiny lizards. One snake was the size of a boa constrictor, large enough to take the eggs and young of many dinosaur species. Iguana-like plant-eating lizards inhabited the southwest, while carnivorous lizards hunted through the swamps and flood plains of what is now Montana, some of them up to six feet long.
“Lizards and snakes rivaled the dinosaurs in terms of diversity, making it just as much an ‘Age of Lizards’ as an ‘Age of Dinosaurs,'” Longrich said.
The scientists then conducted a detailed analysis of the relationships of these reptiles, showing that many represented archaic lizard and snake families that disappeared at the end of the Cretaceous, following the asteroid strike.
One of the most diverse lizard branches wiped out was the Polyglyphanodontia. This broad category of lizards included up to 40 percent of all lizards then living in North America, according to the researchers. In reassessing previously collected fossils, they came across an unnamed species and called it Obamadon gracilis. In Latin, odon means “tooth” and gracilis means “slender.”
“It is a small polyglyphanodontian distinguished by tall, slender teeth with large central cusps separated from small accessory cusps by lingual grooves,” the researchers write of Obamadon, which is known primarily from the jaw bones of two specimens. Longrich said the creature likely measured less than one foot long and probably ate insects.
He said no one should impute any political significance to the decision to name the extinct lizard after the recently re-elected U.S. president: “We’re just having fun with taxonomy.”
The mass (but not total) extinction of snakes and lizards paved the way for the evolution and diversification of the survivors by eliminating competitors, the researchers said. There are about 9,000 species of lizard and snake alive today. “They didn’t win because they were better adapted, they basically won by default, because all their competitors were eliminated,” Longrich said.
Co-author Bhart-Anjan S. Bhullar, a doctoral student in organismic and evolutionary biology at Harvard University, said: “One of the most important innovations in this work is that we were able to precisely reconstruct the relationships of extinct reptiles from very fragmentary jaw material. This had tacitly been thought impossible for creatures other than mammals. Our study then becomes the pilot for a wave of inquiry using neglected fossils and underscores the importance of museums like the Yale Peabody as archives of primary data on evolution — data that yield richer insights with each new era of scientific investigation.”
Jacques A. Gauthier, professor of geology and geophysics at Yale and curator of vertebrate paleontology and vertebrate zoology, is also an author.
The paper is titled “Mass Extinction of Lizards and Snakes at the Cretaceous-Paleogene Boundary.” The National Science Foundation and the Yale Institute for Biospheric Studies supported the research.
Scientists Find Oldest Dinosaur — Or Closest Relative Yet
ScienceDaily (Dec. 4, 2012) — Researchers have discovered what may be the earliest dinosaur, a creature the size of a Labrador retriever, but with a five foot-long tail, that walked the Earth about 10 million years before more familiar dinosaurs like the small, swift-footed Eoraptor and Herrerasaurus.
The findings mean that the dinosaur lineage appeared 10 million to 15 million years earlier than fossils previously showed, originating in the Middle Triassic rather than in the Late Triassic period.
“If the newly named Nyasasaurus parringtoni is not the earliest dinosaur, then it is the closest relative found so far,” according to Sterling Nesbitt, a University of Washington postdoctoral researcher in biology and lead author of a paper published online Dec. 5 in Biology Letters, a journal of the United Kingdom’s Royal Society.
“For 150 years, people have been suggesting that there should be Middle Triassic dinosaurs, but all the evidence is ambiguous,” he said. “Some scientists used fossilized footprints, but we now know that other animals from that time have a very similar foot. Other scientists pointed to a single dinosaur-like characteristic in a single bone, but that can be misleading because some characteristics evolved in a number of reptile groups and are not a result of a shared ancestry.”
The researchers had one humerus — or upper arm bone — and six vertebrae to work with. They determined that the animal likely stood upright, measured 7 to 10 feet in length (2 to 3 meters), was as tall as 3 feet at the hip (1 meter) and may have weighed between 45 and 135 pounds (20 to 60 kilograms).
The fossilized bones were collected in the 1930s from Tanzania, but it may not be correct to say dinosaurs originated in that country. When Nyasasaurus parringtoni lived, the world’s continents were joined in the landmass called Pangaea. Tanzania would have been part of Southern Pangaea that included Africa, South America, Antarctica and Australia.
“The new findings place the early evolution of dinosaurs and dinosaur-like reptiles firmly in the southern continents,” said co-author Paul Barrett at the Natural History Museum, London.
The bones of the new animal reveal a number of characteristics common to early dinosaurs and their close relatives. For example, the bone tissues in the upper arm bone appear as if they are woven haphazardly and not laid down in an organized way. This indicates rapid growth, a common feature of dinosaurs and their close relatives.
“We can tell from the bone tissues that Nyasasaurus had a lot of bone cells and blood vessels,” said co-author Sarah Werning at the University of California, Berkeley, who did the bone analysis. “In living animals, we only see this many bone cells and blood vessels in animals that grow quickly, like some mammals or birds.”
“The bone tissue of Nyasasaurus is exactly what we would expect for an animal at this position on the dinosaur family tree,” she added. “It’s a very good example of a transitional fossil; the bone tissue shows that Nyasasaurus grew about as fast as other primitive dinosaurs, but not as fast as later ones.”
Another example is the upper arm bone’s distinctively enlarged crest, needed to anchor the upper arm muscles. The feature, known as an elongated deltopectoral crest, is also common to all early dinosaurs.
“Nyasasaurus and its age have important implications regardless of whether this taxon is a dinosaur or the closest relatives of dinosaurs,” Nesbitt said. “It establishes that dinosaurs likely evolved earlier than previously expected and refutes the idea that dinosaur diversity burst onto the scene in the Late Triassic, a burst of diversification unseen in any other groups at that time.”
It now appears that dinosaurs were just part of a large diversification of archosaurs. Archosaurs were among the dominant land animals during the Triassic period 250 million to 200 million years ago and include dinosaurs, crocodiles and their kin.
“Dinosaurs are just part of this archosaur diversification, an explosion of new forms soon after the Permian extinction,” Nesbitt said.
The specimen used to identify the new species is part of the collection at the Natural History Museum, London. Four vertebrae from a second specimen of Nyasasaurus, which were also used in this research, are housed in the South African Museum in Cape Town. The work was funded by the National Science Foundation and the Natural History Museum, London. The fourth co-author on the paper is Christian Sidor, UW professor of biology.
The name Nyasasaurus parringtoni is new, but “Nyasasaurus” — combining the lake name Nyasa with the term “saurus” for lizard — is not. The late paleontologist Alan Charig, included as a co-author on the paper, named the specimen but never documented or published in a way that was formally recognized. “Parringtoni” is in honor of University of Cambridge’s Rex Parrington, who collected the specimens in the 1930s.
“What’s really neat about this specimen is that it has a lot of history. Found in the ’30s, first described in the 1950s but never published, then its name pops up but is never validated. Now 80 years later, we’re putting it all together,” Nesbitt said.
“This work highlights the important role of museums in housing specimens whose scientific importance might be overlooked unless studied and restudied in detail,” Barrett said. “Many of the more important discoveries in paleontology are made in the lab, or museum storerooms, as well as in the field.”