Fossil pollen ‘sneeze’ caught by research team

Like capturing a sneeze, researchers including a University of Guelph scientist have recorded the only known example of prehistoric pollen caught in explosive mid-discharge from a fossil flower.

The team describes this “freeze-frame” fossilized pollen release — preserved in amber more than 20 million years ago — in a paper describing a new genus of fossil nettle plants.

The researchers captured on camera pollen explosions.

The paper is co-authored by Peter Kevan, emeritus professor in the School of Environmental Sciences. It appears in the journal Botany alongside another paper by a second team that also includes the U of G researcher.

That second paper looks at a modern-day plant relative in Latin America that is surprising researchers with its use of explosive pollen release, a fair-weather dispersal method seemingly ill-suited to its home in humid tropical rainforests.

In their fossil paper, Kevan and his co-authors describe a new genus (Ekrixanthera, meaning “explosive anther”) containing two new species of extinct plants related to modern-day nettles.

These fossil plants were preserved during the mid-Tertiary period, said Kevan. By then, dinosaurs were long-extinct and non-human mammals roamed Earth.

The samples came from the Dominican Republic and Mexico.

One Mexican sample has preserved pollen grains caught in mid-discharge from the male plant’s anther.

This pollen burst normally takes less than one-tenth of a second, said Kevan. “It’s remarkable that it was captured. It’s like catching a sneeze.”

He was asked to help identify the plants by lead author George Poinar Jr., an expert on amber fossils at Oregon State University.

“We ended up with the new genus because the flowers do not match those of any modern species,” said Kevan. “This tells us something about how old that group of plants is, and that this pollination mechanism goes back a long way.”

That form of pollen dispersal is also described in the second paper about modern-day tropical nettles. Boehmeria caudata grows from southern North America to northern Argentina.

Explosive pollen release is “something you don’t expect in the rainforest. Pollen blasted into the air is likely to get rained out.”

Most tropical plants rely instead on such creatures as insects, bats and birds rather than wind pollination, said Kevan.

In this group of nettles, the male plant disperses its pollen during short dry periods. Even during the rainy season, short sunny periods of high heat and low humidity trigger pollen release.

Drying causes parts of its stamens to shrink unevenly. Physical tension ruptures the anther to release an explosive burst of pollen.

That quick-release mechanism propels pollen into air currents and allows the male flowers to react to short-term weather conditions.

Kevan’s co-authors are students at the University of Sao Paulo led by Paula Maria Montoya-Pfeiffer. They studied Boehmeria during a pollination course taught in Brazil by Kevan in late 2014.

He and colleagues have taught that course in several Latin American countries for decades.

A rare small specimen discovered from the age of flying giants

A rare small-bodied pterosaur, a flying reptile from the Late Cretaceous period approximately 77 million years ago, is the first of its kind to have been discovered on the west coast of North America.

Pterosaurs are the earliest vertebrates known to have evolved powered flight.

The specimen is unusual as most pterosaurs from the Late Cretaceous were much larger with wingspans of between four and eleven metres (the biggest being as large as a giraffe, with a wingspan of a small plane), whereas this new specimen had a wingspan of only 1.5 metres.

The fossils of this animal are the first associated remains of a small pterosaur from this time, comprising a humerus, dorsal vertebrae (including three fused notarial vertebrae) and other fragments. They are the first to be positively identified from British Columbia, Canada and have been identified as belonging to an azhdarchoid pterosaur, a group of short-winged and toothless flying reptiles which dominated the final phase of pterosaur evolution.

Previous studies suggest that the Late Cretaceous skies were only occupied by much larger pterosaur species and birds, but this new finding, which is reported in the Royal Society journal Open Science, provides crucial information about the diversity and success of Late Cretaceous pterosaurs.

Lead author of the study Elizabeth Martin-Silverstone, a Palaeobiology PhD Student at the University of Southampton, said: “This new pterosaur is exciting because it suggests that small pterosaurs were present all the way until the end of the Cretaceous, and weren’t outcompeted by birds. The hollow bones of pterosaurs are notoriously poorly preserved, and larger animals seem to be preferentially preserved in similarly aged Late Cretaceous ecosystems of North America. This suggests that a small pterosaur would very rarely be preserved, but not necessarily that they didn’t exist.”

The fossil fragments were found on Hornby Island in British Columbia in 2009 by a collector and volunteer from the Royal British Columbia Museum, who then donated them to the Museum. At the time, it was given to Victoria Arbour, a then PhD student and dinosaur expert at the University of Alberta. Victoria, as a postdoctoral researcher at North Carolina State University and the North Carolina Museum of Natural Sciences, then contacted Elizabeth and the Royal BC Museum sent the specimen for analysis in collaboration with Dr Mark Witton, a pterosaur expert at the University of Portsmouth.

Dr Witton said: “The specimen is far from the prettiest or most complete pterosaur fossil you’ll ever see, but it’s still an exciting and significant find. It’s rare to find pterosaur fossils at all because their skeletons were lightweight and easily damaged once they died, and the small ones are the rarest of all. But luck was on our side and several bones of this animal survived the preservation process. Happily, enough of the specimen was recovered to determine the approximate age of the pterosaur at the time of its death. By examining its internal bone structure and the fusion of its vertebrae we could see that, despite its small size, the animal was almost fully grown. The specimen thus seems to be a genuinely small species, and not just a baby or juvenile of a larger pterosaur type.”

Elizabeth Martin-Silverstone added: “The absence of small juveniles of large species — which must have existed — in the fossil record is evidence of a preservational bias against small pterosaurs in the Late Cretaceous. It adds to a growing set of evidence that the Late Cretaceous period was not dominated by large or giant species, and that smaller pterosaurs may have been well represented in this time. As with other evidence of smaller pterosaurs, the fossil specimen is fragmentary and poorly preserved: researchers should check collections more carefully for misidentified or ignored pterosaur material, which may enhance our picture of pterosaur diversity and disparity at this time.”

The benefits of commercial fossil sales to 21st-century paleontology

Authors: Peter L. Larson and Donna Russell

Article number: 17.1.2E
Published April 2014

The luckiest people on this planet are the ones that have also made their passion their career. This is equally true for vertebrate paleontologists and commercial fossil dealers. We have other things in common as well. We all agree that fossils are important. We agree that it is our responsibility to educate the public about fossils. And we agree that scientifically important specimens should be in museums.

Fossils have been collected, bartered, bought and sold for thousands of years (Mayor 2000). Commercialism has remained a crucial and functionally key element of paleontology throughout its history. Although all facets of paleontology are permeated with continuing scientific contributions by commercial entities (Manning 2001), this essay will only reference a few of the more notable.

In Europe, much of what we know about the Jurassic marine faunas and environments of the Posidonia Shale Lagerstätten of Holzmaden (Germany), and the Blue Lias of Lyme Regis, Dorset (England) are based upon collections made by people who sold fossils. Mary Anning, an iconic person in the field of paleontology, is one of the more famous commercial collectors. Academics and curators at British institutions accepted Anning as a colleague, despite her lack of a formal degree or position at a university (McGowan 2001, Emling 2009). A congenial and civilized working relationship still exists today in England between commercial “professional” collectors and museum and university academics (Manning 2001).

In Germany the government actively buys important specimens from private collectors (Rupert Wild, personal communication). The production of fossils from the Messel Lagerstätten was increased more than a thousand-fold by the work and ingenuity of commercial and private collectors. Most of the specimens that have been saved from these Eocene lake deposits are the result of a preparation transfer of the fossil to a resin matrix, a technique first pioneered by commercial collectors (Thomas Perner and Jurgen Henzel, personal communication). This new method permitted the recovery of articulated vertebrate remains with skin, feathers and stomach contents (Schaal and Ziegler 1992). One commercially collected specimen, a complete primate described and named Darwinius masillae, was suggested to be a pivotal “link” in the phylogenetic tree of our own species (Tudge 2009).

The Solnhofen area is one of the most important fossil sites in Germany and is still collected almost exclusively by people who sell the fossils they collect. This site has been operated commercially since the advent of the lithographic printing process in 1798 (Barthel et al. 1990). The Solnhofen Limestone has produced some of the most important fossils in the study of evolution, including the iconic early bird Archaeopteryx (Bergmann et al 2010). Every single specimen of Archaeopteryx known to science has been bought and sold (Ostrom 1985, Barthel et al. 1990).

Interestingly, the specimen of Archaeopteryx that is today one of the most accessible to the scientific community and the public is the Thermopolis specimen, in the private Wyoming Dinosaur Center, in Thermopolis (Wyoming, USA). This specimen has been displayed in Canada, China, Europe, Japan, and the US. It has been molded, photographed, Micro-CT scanned, laser-scanned and XRF scanned, and has generated multiple high-impact publications (Mayer et al. 2005, Bergmann et al. 2010). Despite this excellent academic work, some paleontologists have raised concerns on the ethics of publishing such material. For example, an academic paleontologist interviewed by the Los Angeles Times on 19 March 2006, stated “Ethically, in our profession, if a specimen is not in the public domain, its scientific worth is about zero.”

One particular site that has shed vital clues on the evolution of birds from dinosaurs was discovered in the 1990’s near Liaoning, China. Here farmers, turned commercial fossil collectors, have been excavating Lower Cretaceous lake deposits since the 1930’s. Then as today, these collectors sell their discoveries to scientists and the public alike. Virtually every fossil of scientific importance from these deposits has been bought and sold. These include thousands of fossil birds, some with exquisitely preserved plumage whose chemistry has been resolved and the pigmentation of feathers constrained (Wogelius et al. 2011). Perhaps the greatest scientific advancement derived from these commercially collected fossils is the irrefutable evidence that theropods had feathers and indeed extant birds are derived theropods (Currie and Chen 2001, Norell and Xu 2005. and Xu et al. 2010, etc.).

Morocco has, perhaps, the largest per-capita population of commercial fossil collectors of any country, with an estimated 50,000 collectors and annual fossil sales totaling $40,000,000.00 (Sicree 2009). These collectors and their activities are protected by law and the Ministere de l’Energie des Mines. Fossils are legally exported, but foreigners may not collect fossils unless it benefits the local commercial collectors (Sicree 2009, Bardet et al. 2010, Frommers 2014). Thus publications of Moroccan fossils must include discussions of fossils that were purchased (Bardet et al. 2010, Murray and Wilson 2014). In the open pit mines, huge machines excavate the Maestrichtian and Palaeogene aged phosphate deposits. Commercial collectors extract any fossils exposed by the latest pass of the machines and are responsible for most of what we know about this rich, but otherwise inaccessible fauna (Bardet et al. 2010, Bardet et al. 2013).

In the United States, the buying and selling of fossils has always been a part of paleontology. Marsh and Cope competed to purchase the latest discovery, whether it was a single bone, or a train car full of them, there was a desire to beat the other scientist to publication (Jaffe 2000). At the end of the 19th century, the Sternberg family began hunting fossils in the western United States and selling them throughout the world. Beginning with Charles H. and ending with George, the Sternbergs collected and sold anything from titanotheres to dinosaur mummies (Manning 2008). The dynasty even had one of its members, Charles M. Sternberg, accepted into the academic community (Rogers 1999).

If not for commercial fossil collecting in the lacustrine Green River Formation, little would be known beyond the five most common fish. It is only because of commercial quarries, that we have a more complete picture of the life in and around “Fossil Lake.” Without 100-plus commercial collectors over the last 100 years splitting limestone to collect fish after fish, science would never have seen the articulated mammals, lizards, snakes, and rarer fish, nor the feathered birds and all the plants and invertebrates that these diggers have produced (Grande 1984, Grande 2013).

Today, in the United States, commercial fossil collectors are barred from collecting fossils on Federal Land, but the rights of private landowners and the private ownership of fossils is maintained (The Paleontological Resources Preservation Act of 2009). Commercial collectors work legally on private land, and the landowners benefit financially from this activity, and thus are interested in the fossils on their land. The best of these collectors also work hand in hand with academics at both universities and museums. They employ scientists to help with data retrieval, restoration, mounting and finding the appropriate researchers to contact (Black Hills Institute, Siber & Siber, Triebold Paleontology, etc.).

New and important dinosaur specimens from the Morrison Formation (McIntosh et al. 1996, Redelstorff and Sander 2009, etc.), the Two Medicine Formation (Burnham et al. 2000, Evans and Larson 2003, etc.), and the Judith River Formation (Stein and Triebold 2013, Ott and Larson in press, etc.) have been recently discovered by commercial paleontologists and placed in museums, following the codes of ethics of the Association of Applied Paleontological Sciences, the Paleontological Society and the Society of Vertebrate Paleontology.

Some of the greatest contributions by commercial collectors have come from the Terminal Cretaceous Lance and Hell Creek Formations. These rocks have been reluctant to yield complete specimens because of a slow depositional environment and fragile, friable fossils that are difficult to collect. Commercial collectors applied their innovative techniques to the problem and discovered and collected vertebrates that would have otherwise never been seen by academic paleontologists, or the public. The most significant of these discoveries have ended up in museums. These include some of the most complete skeletons of Tyrannosaurus rex (Larson and Donnan 2002, Brochu 2003, N. Larson 2008, P. Larson 2008), Edmontosaurus (Christians 1992), Triceratops (The Childrens Museum in Indianapolis; Houston Museum of Natural Science; National Science Museum, Tokyo), a new Ceratopsian (Ott and Larson 2010) and a brand new oviraptorosaurian theropod (Lamanna et al. 2014).

This is by no means a comprehensive list of recent contributions by commercial collectors to the science of vertebrate paleontology, but it should provide a sense of the scope and scale of those significant contributions. Shimada et al. (2014), in contrast, suggest that recent developments in commercial collecting are actually damaging to the science and cite three examples. These examples are worthy of additional discussion and we thank Shimada et al. (2014) for raising these particular cases.

The first case is that of a skeleton of Tarbosaurus that was illegally collected, smuggled out of Mongolia and appeared at an auction in 2012. This is indeed a clear example of illegal activity that was thwarted by paleontologists working with law enforcement agencies. Commercial collectors applauded these actions because any illegal specimens that appear on the market unfairly compete with legal fossils. No fossil enthusiast approves of the destruction of sites or the theft and damage of specimens by those who work outside the law.

The second example was a 2013 bill (“HB 392”) that proposed allowing sales of fossils from Makoshika State Park in Glendive, Montana. This bill was passed by the Montana House for consideration by the State Senate. Although this might have been a naive move by a state representative or a park official, there is simply no evidence that the bill was the brainchild of commercial fossil collectors. In this case, the bill never made it out of the Senate.

The third and final case that Shimada et al. (2014) raise relates to the San Diego Museum of Natural History contracting with Bonhams to auction specimens originally purchased from C.H. Sternberg. Although the specimens had historical significance, they were of well-known and often duplicated taxa. “The Museum intended to use the money generated by the sale to purchase an important local fossil collection” (www.sdnhm.org/blog_details/fossils-withdrawn-from-auction/9/). Because of the public outcry from academic paleontologists (Perlman 2013) the specimens were withdrawn from the auction.

Shimada et al. (2014) stated: “We therefore consider the battle against heightened commercialization of fossils to be the greatest challenge to paleontology of the 21st century.” We believe, on the other hand, that the demonization and marginalization of a specific portion of the paleontological community is the result of misunderstanding, misplaced entitlement and simple intolerance. Such attitudes endanger the future of the very science of paleontology and paleontological collections on which it is based. Through collaboration, education and constructive alliances, the fossil fuel that drives our discipline could be better managed and made more easily accessible to the scientists who work in both commercial and/or academic institutions, but more importantly, made equally accessible to the public.

A recent Gallup poll (gallup.com/poll/21814/evolution-creationism-intelligent-design.aspx) shows that 46% of Americans believe that God created humans in their present form. The same poll revealed that 66% of Americans believe that the Earth is less than 10,000 years old. Fifty-four percent believe that creationism should be taught in schools. The challenges that our discipline faces are grave and we need a united front so that we might work together to make fossils more available to the general public, in museums and private collections, so that more people can touch, learn and understand the beautiful story that is the evolutionary history of life on Earth.

We must not forget that many of today’s public museums started out as private collections (Carnall 2013). Instead of castigating private collectors for their scientific curiosity and desire to collect, purchase or sell fossils, scientists would do far better by welcoming them into the fold. This would go a long way in helping to solve two real problems recognized by Shimada et al. (2014): a shrinking job market and diminishing funding sources.

Private collections also have a legitimate role in the preservation and study of our planetary heritage. Most private collectors gladly open their doors to any interested scientist and many readily donate specimens or money to research programs. The historical value of well-curated collections often end as bequests to museums. It is fair to say that this does necessitate patience on behalf of paleontologists wishing to house such collections, but this is the perfect reason to work with collectors to ensure a partnership that will help in the curation, conservation and preparation of samples and ultimately in its accession to a collection. To castigate such dedicated passion for our past can only be detrimental to the future of the science.

Although Shimada et al. (2014) are not alone in their beliefs, most paleontologists do not share their views; “[W]orking with private and amateur collectors can very realistically improve our knowledge about the natural world” (Carnall 2013). The Paleontological Society’s code of ethics states: “The principal importance of fossils is for scientific, scholarly, and educational use of both professionals and amateurs” (www.paleosoc.org/pscode.htm). They further state: “To leave fossils uncollected assures their degradation and ultimate loss to the scientific and educational world through natural processes of weathering and erosion.” In the National Academy of Sciences report on Paleontological Collecting (Raup et al. 1986), the committee not only recognize the contributions to paleontology by commercial and amateur collectors as are their rights on private lands, but also recommended that regulated amateur and commercial collecting be allowed on public lands.

People collect fossils because of scientific curiosity. They come from all walks of life. A very lucky few are able to find work as paleontologists in universities or museums. Others create companies that collect, buy and sell fossils. Some satiate their passion as volunteers or by maintaining fossil collections that are often eventually donated to their local museum. Working in partnership we can all help to solve the contracting job market and diminishing public funds for paleontological research and exhibits. However, if we remain divided…we may not fall, but simply fail the science at a time when we should be celebrating advances in the remarkable techniques and technology available to us in the 21st Century.

It is our humble opinion that the real “Greatest Challenge to Paleontology of the 21st Century”, is finding a way for amateurs, commercial fossil dealers and academic paleontologists to work together and do what is best for the public and the fossils. It’s the only way the science will thrive.

ACKNOWLEDGEMENTS

Thanks to P. J. Currie and P. L. Manning for reviewing this paper.

Whale fossil, 17 million years old, provides first exact date for East Africa’s puzzling uplift

Uplift associated with the Great Rift Valley of East Africa and the environmental changes it produced have puzzled scientists for decades because the timing and starting elevation have been poorly constrained.

Now paleontologists have tapped a fossil from the most precisely dated beaked whale in the world — and the only stranded whale ever found so far inland on the African continent — to pinpoint for the first time a date when East Africa’s mysterious elevation began.
The 17 million-year-old fossil is from the beaked Ziphiidae whale family. It was discovered 740 kilometers inland at an elevation of 620 meters in modern Kenya’s harsh desert region, said vertebrate paleontologist Louis L. Jacobs, Southern Methodist University, Dallas.
At the time the whale was alive, it would have been swimming far inland up a river with a low gradient ranging from 24 to 37 meters over more than 600 to 900 kilometers, said Jacobs, a co-author of the study.
The study, published in the Proceedings of the National Academy of Sciences, provides the first constraint on the start of uplift of East African terrain from near sea level.
“The whale was stranded up river at a time when east Africa was at sea level and was covered with forest and jungle,” Jacobs said. “As that part of the continent rose up, that caused the climate to become drier and drier. So over millions of years, forest gave way to grasslands. Primates evolved to adapt to grasslands and dry country. And that’s when — in human evolution — the primates started to walk upright.”
Identified as a Turkana ziphiid, the whale would have lived in the open ocean, like its modern beaked cousins. Ziphiids, still one of the ocean’s top predators, are the deepest diving air-breathing mammals alive, plunging to nearly 10,000 feet to feed, primarily on squid.
In contrast to most whale fossils, which have been discovered in marine rocks, Kenya’s beached whale was found in river deposits, known as fluvial sediments, said Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences of SMU’s Dedman College of Humanities and Sciences. The ancient large Anza River flowed in a southeastward direction to the Indian Ocean. The whale, probably disoriented, swam into the river and could not change its course, continuing well inland.
“You don’t usually find whales so far inland,” Jacobs said. “Many of the known beaked whale fossils are dredged by fishermen from the bottom of the sea.”
Determining ancient land elevation is very difficult, but the whale provides one near sea level.
“It’s rare to get a paleo-elevation,” Jacobs said, noting only one other in East Africa, determined from a lava flow.
Beaked whale fossil surfaced after going missing for more than 30 years
The beaked whale fossil was discovered in 1964 by J.G. Mead in what is now the Turkana region of northwest Kenya.
Mead, an undergraduate student at Yale University at the time, made a career at the Smithsonian Institution, from which he recently retired. Over the years, the Kenya whale fossil went missing in storage. Jacobs, who was at one time head of the Division of Paleontology for the National Museums of Kenya, spent 30 years trying to locate the fossil. His effort paid off in 2011, when he rediscovered it at Harvard University and returned it to the National Museums of Kenya.
The fossil is only a small portion of the whale, which Mead originally estimated was 7 meters long during its life. Mead unearthed the beak portion of the skull, 2.6 feet long and 1.8 feet wide, specifically the maxillae and premaxillae, the bones that form the upper jaw and palate.
The researchers reported their findings in “A 17 million-year-old whale constrains onset of uplift and climate change in East Africa” online at the PNAS web site.
Modern cases of stranded whales have been recorded in the Thames River in London, swimming up a gradient of 2 meters over 70 kilometers; the Columbia River in Washington state, a gradient of 6 meters over 161 kilometers; the Sacramento River in California, a gradient of 4 meters over 133 kilometers; and the Amazon River in Brazil, a gradient of 1 meter over 1,000 kilometers.

Plants survive better through mass extinctions than animals

At least 5 mass extinction events have profoundly changed the history of life on Earth. But a new study led by researchers at the University of Gothenburg shows that plants have been very resilient to those events.

For over 400 million years, plants have played an essential role in almost all terrestrial environments and covered most of the world’s surface. During this long history, many smaller and a few major periods of extinction severely affected Earth’s ecosystems and its biodiversity.
In the upcoming issue of the journal New Phytologist, the team reports their results based on more than 20,000 plant fossils with the aim to understand the effects of such dramatic events on plant diversity. Their findings show that mass extinction events had very different impacts among plant groups. Negative rates of diversification in plants (meaning that more species died out than new species were formed) were never sustained through long time periods. This indicates that, in general, plants have been particularly good at surviving and recovering through tough periods.
“In the plant kingdom, mass extinction events can be seen as opportunities for turnover leading to renewed biodiversity,” says leading author Daniele Silvestro.
Most striking were the results for the Cretaceous-Paleogene mass extinction, caused by the impact of an asteroid off the Mexican coast some 66 million years ago. This event had a great impact on the configuration of terrestrial habitats and led to the extinction of all dinosaurs except birds, but surprisingly it had only limited effects on plant diversity.
Some important plant groups, such as the gymnosperms (including pines, spruce and firs) lost a great deal of their diversity through extinction. On the other hand, flowering plants (angiosperms) did not suffer from increased extinction, and shortly after the impact they underwent a new rapid increase in their diversity. These evolutionary dynamics contributed to make flowering plants dominate today’s global diversity above all other plant groups.
“Mass extinctions are often thought as a bad thing, but they have been crucial in changing the world into how we know it today,” says senior author Alexandre Antonelli.
If that asteroid had not struck the Earth, chances are that large dinosaurs would still be hunting around, mammals would be small and hiding in caves, and humans might never have evolved.
“By studying such extreme events we are trying to learn which groups of organisms and features are more sensitive to changes, so that we can apply this knowledge to protect biodiversity in the face of on-going climate change and human deterioration of natural ecosystems,” concludes Antonelli.

Swimming reptiles make their mark in the Early Triassic

Vertebrate tracks provide valuable information about animal behavior and environments. Swim tracks are a unique type of vertebrate track because they are produced underwater by buoyant trackmakers, and specific factors are required for their production and subsequent preservation. Early Triassic deposits contain the highest number of fossil swim track occurrences worldwide compared to other epochs, and this number becomes even greater when epoch duration and rock outcrop area are taken into account.

This spike in swim track occurrences suggests that during the Early Triassic, factors promoting swim track production and preservation were more common than at any other time. Coincidentally, the Early Triassic period follows the largest mass extinction event in Earth’s history, and the fossil record indicates that a prolonged period of delayed recovery persisted throughout this time period.
During this recovery interval, sediment mixing by animals living within the substrate was minimal, especially in particularly stressful environments such as marine deltas. The general lack of sediment mixing during the Early Triassic was the most important contributing factor to the widespread production of firm-ground substrates ideal for recording and preserving subaqueous trace fossils like swim tracks.

Giant rodent used incisors like tusks

The largest rodent ever to have lived may have used its front teeth just like an elephant uses its tusks, a new study led by scientists at the University of York and The Hull York Medical School (HYMS) has found.

Josephoartigasia monesi, a rodent closely related to guinea pigs, lived in South America approximately 3 million years ago. It is the largest fossil rodent ever found, with an estimated body mass of 1000 kg and was similar in size to a buffalo.
Dr Philip Cox, of the Centre for Anatomical and Human Sciences, a joint research centre of the University’s Department of Archaeology and HYMS, used computer modelling to estimate how powerful the bite of Josephoartigasia could be.
He found that, although the bite forces were very large – around 1400 N, similar to that of a tiger – the incisors would have been able to withstand almost three times that force, based on earlier estimates by co-authors, Dr Andres Rinderknecht, of The Museo Nacional de Historia Natural, Montevideo, and Dr Ernesto Blanco, of Facultad de Ciencias, Instituto de Fısica, Montevideo, who first described the fossil in 2008.
Dr Cox said: “We concluded that Josephoartigasia must have used its incisors for activities other than biting, such as digging in the ground for food, or defending itself from predators. This is very similar to how a modern day elephant uses its tusks.”
The research, which is published in the Journal of Anatomy, involved CT scanning the Josephoartigasia monesi specimen and making a virtual reconstruction of its skull. This was then subjected to finite element analysis, an engineering technique that predicts stress and strain in a complex geometric object.

Fossils from heart of Amazon provide evidence that South American monkeys came from Africa

For millions of years, South America was an island continent. Geographically isolated from Africa as a result of plate tectonics more than 65 million years ago, this continent witnessed the evolution of many unfamiliar groups of animals and plants. From time to time, animals more familiar to us today — monkeys and rodents among others — managed to arrive to this island landmass, their remains appearing abruptly in the fossil record. Yet, the earliest phases of the evolutionary history of monkeys in South America have remained cloaked in mystery. Long thought to have managed a long transatlantic journey from Africa, evidence for this hypothesis was difficult to support without fossil data.

A new discovery from the heart of the Peruvian Amazon now unveils a key chapter of the evolutionary saga of these animals. In a paper published February 4, 2015 in the scientific journal Nature, the discovery of three new extinct monkeys from eastern Peru hints strongly that South American monkeys have an African ancestry.
Co-author Dr. Ken Campbell, curator at the Natural History Museum of Los Angeles County (NHM), discovered the first of these fossils in 2010, but because it was so strange to South America, it took an additional two years to realize that it was from a primitive monkey.
Mounting evidence came as a result of further efforts to identify tiny fossils associated with the first find. For many years, Campbell has surveyed remote regions of the Amazon Basin of South America in search for clues to its ancient biological past. “Fossils are scarce and limited to only a few exposed banks along rivers during the dry seasons,” said Campbell. “For much of the year high water levels make paleontological exploration impossible.” In recent years, Campbell has focused his efforts on eastern Peru, working with a team of Argentinian paleontologists expert in the fossils of South America. His goal is to decipher the evolutionary origin of one of the most biologically diverse regions in the world.
The oldest fossil records of New World monkeys (monkeys found in South America and Central America) date back 26 million years. The new fossils indicate that monkeys first arrived in South America at least 36 million years ago. The discovery thus pushes back the colonization of South America by monkeys by approximately 10 million years, and the characteristics of the teeth of these early monkeys provide the first evidence that monkeys actually managed to cross the Atlantic Ocean from Africa.

Two-faced fish clue that our ancestors ‘weren’t shark-like’

An investigation of a 415 million year-old fish skull strongly suggests that the last common ancestor of all jawed vertebrates, including humans, was not very shark-like. It adds further weight to the growing idea that sharks are not ‘primitive’.

The fossil skull’s external features meant it had always been thought to belong to the bony fishes (osteichthyans), a group which includes familiar fishes such as cod and tuna as well as all land-dwelling creatures with backbones. But when scientists from Oxford University and Imperial College London used X-ray CT scanning to look inside the skull they found the structure surrounding the brain was reminiscent of cartilaginous fishes (chondrichthyans) such as sharks and rays. The fish fossil’s ‘two faces’ led to it being named Janusiscus after the double-faced Roman god Janus.
A report of the research is published in the journal Nature.
‘This 415 million year-old fossil gives us an intriguing glimpse of the ‘Age of Fishes’, when modern groups of vertebrates were really beginning to take off in an evolutionary sense,’ said Dr Matt Friedman of Oxford University’s Department of Earth Sciences, an author of the report. ‘It tells us that the ancestral jawed vertebrate probably doesn’t fit into our existing categories.’
Chondrichthyans have often been viewed as primitive, and treated as proxies for what the ‘ancestral’ jawed vertebrate would have looked like. A key component of this view is the lack of a bony skeleton in cartilaginous fishes.
‘The results from our analysis help to turn this view on its head: the earliest jawed vertebrates would have looked somewhat more like bony fishes, at least externally, with large dermal plates covering their skulls,’ said Sam Giles of Oxford University’s Department of Earth Sciences, first author of the report. ‘In fact, they would have had a mix of what are now viewed as cartilaginous- and bony fish-like features, supporting the idea that both groups became independently specialised later in their separate evolutionary histories.’
Dr Friedman said: ‘This mix of features, some reminiscent of bony fishes and others cartilaginous fishes, suggests that humans may have just as many features that you might call ‘primitive’ as sharks.’
The fossil skull was originally found near the Sida River in Siberia in 1972 and is currently held in the Institute of Geology at the Tallinn University of Technology, Estonia. Study author Martin Brazeau of Imperial College London spotted the specimen in an online catalogue and the team decided it would be worth studying in greater detail using modern investigative techniques.
The team then used X-ray CT (computed tomography) to ‘virtually’ cut through the fossil. Different materials attenuate X-rays to different amounts — just as in a hospital X-ray, bones show up brighter than muscles and skin. This same principle can be applied to fossils, as fossilised bone and rock attenuate X-rays to different degrees. This technique was used to build a 3D virtual model of the fossil, enabling its internal and external features to be examined in great detail. Traces left by networks of blood vessels and nerves, often less than 1/100th of a centimetre in diameter, could then be compared to structure in a variety of jawed vertebrate groups, including sharks and bony fishes.
‘Losing your bony skeleton sounds like a pretty extreme adaptation,’ said Dr Friedman, ‘but with remarkable discoveries from China, Janusiscus strongly suggests that that the ancient ancestors of modern sharks and their kin started out just as ‘bony’ as our own ancestors.’

Ancient fossils reveal rise in parasitic infections due to climate change

When seeking clues about the future effects of possible climate change, sometimes scientists look to the past. Now, a paleobiologist from the University of Missouri has found indications of a greater risk of parasitic infection due to climate change in ancient mollusk fossils. His study of clams from the Holocene Epoch (that began 11,700 years ago) indicates that current sea level rise may mimic the same conditions that led to an upsurge in parasitic trematodes, or flatworms, he found from that time. He cautions that an outbreak in human infections from a related group of parasitic worms could occur and advises that communities use the information to prepare for possible human health risks.

rematodes are internal parasites that affect mollusks and other invertebrates inhabiting estuarine environments, which are the coastal bodies of brackish water that connect rivers and the open sea. John Huntley, assistant professor of geological sciences in the College of Arts and Science at MU, studied prehistoric clam shells collected from the Pearl River Delta in China for clues about how the clams were affected by changes caused from global warming and the resulting surge in parasites.
“Because they have soft bodies, trematodes do not leave body fossils,” Huntley said. “However, infected clam shells develop oval-shaped pits where the clam grew around the parasite in order to keep it out; the prevalence of these pits and their makeup provide clues to how the clams adapted to fight trematodes. When compared to documented rises in sea level more than 9,300 years ago, we found that we currently are creating conditions for an increase in trematodes in present-day estuarine environments. This could have harmful implications for both animal and human health, including many of the world’s fisheries.”
Modern-day trematodes will first infest mollusks like clams and snails, which are eaten by shore birds and mammals including humans. Symptoms of infection in humans range from liver and gall bladder inflammation to chest pain, fever, and brain inflammation. The infections can be fatal. At least 56 million people globally suffer from one or more foodborne trematode infections, according to the World Health Organization.
Huntley and his team compared these findings to those from his previous study on clams found in the Adriatic Sea. Using data that includes highly detailed descriptions of climate change and radiocarbon dating Huntley noticed a rising prevalence of pits in the clam shells, indicating a higher prevalence of the parasites during times of sea level rise in both the fossils from China and Italy.
“By comparing the results we have from the Adriatic and our new study in China, we’re able to determine that it perhaps might not be a coincidence, but rather a general phenomenon,” Huntley said. “While predicting the future is a difficult game, we think we can use the correspondence between the parasitic prevalence and past climate change to give us a good road map for the changes we need to make.”