Fossilized water fleas: Evolution of the micro-crustacean group Cladocera

Scientists of the Senckenberg Institute have studied the evolutionary history of the so-called “water fleas.” These tiny crustaceans from the order Cladocera form the basis of the trophic pyramid and therefore play an important role in modern ecosystems. Due to the fact that they are rarely preserved as fossils, little is known about the water fleas’ evolution. In their study, which was recently published in the scientific journal “Earth-Science Reviews,” the team of scientists presents the first comprehensive inventory of all Cladocera fossils in an ecological context. The scientists show that the animals’ morphology has undergone very little change over the course of geological history. Nevertheless, the water fleas demonstrate a high adaptability to changes in environmental conditions.

A search for organisms in any lake or puddle will very likely turn up a representative of the Cladocera. With more than 700 species, these tiny animals — commonly referred to as “water fleas” due to their bouncing locomotion — inhabit almost all types of freshwater environments. “Despite this wealth of species and habitats, little is known about the evolutionary history of the Cladocera,” explains Dr. Kay Van Damme of the Senckenberg Research Institute in Frankfurt, and he continues, “Since the animals do not possess a calcareous shell or carapace, they are only rarely preserved as fossils.”

For the first time, Van Damme and his colleague, Prof. Alexey A. Kotov of the A.N. Severtsov Institute of Ecology and Evolution in Moscow, have now compiled a complete inventory of all known Cladocera species. “The Cladocera constitute a crucial group in our effort to understand the development of freshwater ecosystems throughout geological history,” says Van Damme in explanation of the team’s motivation. Even today, water fleas still form the basis of many food chains, which makes them an important component of aquatic ecosystems.

Moreover, the tiny crustaceans are very sensitive to environmental changes and can thus be used to monitor water quality — for years, the genus Daphnia has served as a model organism in this regard. “In addition, Daphnia is the first representative of the crustaceans whose genome has been published — therefore, water fleas play a similar role in aquatic environmental genomics as does the fruit fly Drosophila in terrestrial environments,” adds Van Damme.

According to the team of researchers, the first representatives of the water fleas appeared in the early Jurassic, about 180 million years ago. “Since then, the basic design of the Cladocera has hardly changed,” says the biologist from Frankfurt, and he continues, “Nevertheless, this ‘living fossil’ was able to adapt very well to a variety of different environmental conditions.” For example, the water fleas developed various defense mechanisms to escape predators. “Daphnia and company were even able to survive the massive extinction event at the Cretaceous/Tertiary boundary, which, among others, claimed all of the terrestrial dinosaurs,” says Van Damme in closing.

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Mammals in age of dinosaurs packed powerful bite

Move over, hyenas and saber-toothed cats; there’s a mammal with an even stronger bite. A new study by Burke Museum and University of Washington paleontologists describes an early marsupial relative called Didelphodon vorax that lived alongside ferocious dinosaurs and had, pound-for-pound, the strongest bite force of any mammal ever recorded.

Published in the journal Nature Communications, the team’s findings suggest mammals were more varied during the Age of Dinosaurs than previously believed. Didelphodon was able to eat a variety of foods, and was likely a scavenger-predator who could eat prey ranging from snails to small dinosaurs.

In addition, the team re-traced the origins of marsupials. Previous theories attribute South America as the origin of marsupials, but anatomical features of the Didelphodon point to marsupials originating in North America 10-20 million years earlier than originally thought, and later dispersing and diversifying in South America.

“What I love about Didelphodon vorax is that it crushes the classic mold of Mesozoic mammals,” Dr. Gregory P. Wilson, Burke Museum Adjunct Curator of Vertebrate Paleontology and University of Washington Associate Professor of Biology, said. “Instead of a shrew-like mammal meekly scurrying into the shadows of dinosaurs, this badger-sized mammal would’ve been a fearsome predator on the Late Cretaceous landscape — even for some dinosaurs.”

All of these findings are made possible by four fossil specimens recently discovered in the 69-66 million-year-old deposits of the Hell Creek Formation in Montana and North Dakota. Prior to these discoveries, the 60 known species of metatherians (marsupials and their closest relatives) from the Cretaceous of North America — including Didelphodon — were almost all identified through fragments of jaw bones or teeth, providing a limited glimpse into marsupials’ closest relatives. These four fossils include a nearly-complete skull from the North Dakota Geological Survey State Fossil collection, a partial snout and an upper jaw bone from the Burke Museum’s collections, and another upper jaw from the Sierra College Natural History Museum.

By analyzing never-before-seen parts of Didelphodon’s anatomy, Dr. Wilson and his colleagues were able to determine these marsupial relatives were about the size of today’s Virginia opossum and were the largest metatherian from the Cretaceous. With a nearly complete skull to measure, they were able to estimate the overall size of Didelphodon, which ranged from 5.3-11.5 pounds. To test the bite force of Didelphodon, Abby Vander Linden, a UW Biology research technician in Burke Museum Curator of Mammalogy Dr. Sharlene Santana’s lab and now a graduate student at University of Massachusetts Amherst, CT-scanned the fossils and compared the gaps in reconstructed skulls where jaw muscles would go to present-day mammals with known bite forces. Bite force measurements indicate that pound-for-pound, Didelphodon had the strongest bite force of any mammal that has ever lived. In addition to the bite force, Didelphodon’s canines were similar to living felines and hyenas — suggesting they could handle biting into bone, biting deep and killing prey. Its shearing molars and big rounded premolars, combined with powerful jaws and jaw muscles indicate it had a specific niche in the food web as a predator or scavenger capable of crushing hard bone or shells, and was capable of eating prey as big as it was — even possibly small dinosaurs.

“I expected Didelphodon to have a fairly powerful bite based on the robust skull and teeth, but even I was surprised when we performed the calculations and found that, when adjusted for body size, it was capable of a stronger pound-for-pound bite than a hyena,” Vander Linden said. “That’s a seriously tough mammal.”

Co-author Dr. Jonathan Calede, former UW Biology graduate student and now a visiting assistant professor at Bucknell University, also examined “microwear” patterns, or tiny pits and scratches on the specimens’ teeth, to indicate what the animals were eating as their “last suppers” (most likely one-to-two days before the animals died). By comparing the microwear patterns from Didelphodon to the teeth of other fossilized species and current-day mammals with known diets from the Burke’s mammal collection, Calede found Didelphodon was an omnivore that likely consumed a range of vertebrates, plants and hard-shelled invertebrates like molluscs and crayfish, but few insects, spiders and annelids (earthworms and leeches).

“The interesting thing about these fossils is that they allowed us to study the ecology of Didelphodon from many angles,” Calede said. “The strength of the conclusions come from the convergence of microwear with bite force analysis, studies of the shape and breakage of the teeth, as well as the shape of the skull as a whole.”

In addition to learning much more about the biology of Didelphodon, the newly-described skull features on these fossils provide clues that help clarify the origin of all marsupials. The team found five major lineages of marsupial ancestors and marsupials themselves diverged in North America 100-85 million years ago. Marsupial relatives also got larger and ate a wider variety of foods, coinciding with an increase in diversity of other early mammals and flowering plants. Most of this North American diversity was then lost gradually from the late Campanian to Maastrichtian (79-66 million-years-ago) and then abruptly during the Cretaceous-Palaeogene (66 million-years-ago) mass extinction that also killed all dinosaurs except birds. Around this time, marsupials’ diversity and evolution shifted to South America.

“Our study highlights how, despite decades of paleontology research, new fossil discoveries and new ways of analyzing those fossils can still fundamentally impact how we view something as central to us as the evolution of our own clade, mammals,” Dr. Wilson said.

Amber specimen offers rare glimpse of feathered dinosaur tail

Researchers from China, Canada, and the University of Bristol have discovered a dinosaur tail complete with its feathers trapped in a piece of amber.

The finding reported today in Current Biology helps to fill in details of the dinosaurs’ feather structure and evolution, which can’t be surmised from fossil evidence.

While the feathers aren’t the first to be found in amber, earlier specimens have been difficult to definitively link to their source animal, the researchers say.

Ryan McKellar, from the Royal Saskatchewan Museum in Canada, said: “The new material preserves a tail consisting of eight vertebrae from a juvenile; these are surrounded by feathers that are preserved in 3D and with microscopic detail.

“We can be sure of the source because the vertebrae are not fused into a rod or pygostyle as in modern birds and their closest relatives. Instead, the tail is long and flexible, with keels of feathers running down each side. In other words, the feathers definitely are those of a dinosaur not a prehistoric bird.”

The study’s first author Lida Xing from the China University of Geosciences in Beijing discovered the remarkable specimen at an amber market in Myitkyina, Myanmar in 2015.

The amber piece was originally seen as some kind of plant inclusion and destined to become a curiosity or piece of jewellery, but Xing recognized its potential scientific importance and suggested the Dexu Institute of Palaeontology buy the specimen.

The researchers say the specimen represents the feathered tail of a theropod preserved in mid-Cretaceous amber about 99 million years ago. While it was initially difficult to make out details of the amber inclusion, Xing and his colleagues relied on CT scanning and microscopic observations to get a closer look.

The feathers suggest the tail had a chestnut-brown upper surface and a pale or white underside. The specimen also offers insight into feather evolution. The feathers lack a well-developed central shaft or rachis. Their structure suggests that the two finest tiers of branching in modern feathers, known as barbs and barbules, arose before a rachis formed.

Professor Mike Benton from the School of Earth Sciences at the University of Bristol, added: “It’s amazing to see all the details of a dinosaur tail — the bones, flesh, skin, and feathers — and to imagine how this little fellow got his tail caught in the resin, and then presumably died because he could not wrestle free.

“There’s no thought that dinosaurs could shed their tails, as some lizards do today.”

The researchers also examined the chemistry of the tail inclusion where it was exposed at the surface of the amber. The analysis shows that the soft tissue layer around the bones retained traces of ferrous iron, a relic left over from haemoglobin that was also trapped in the sample.

The findings show the value of amber as a supplement to the fossil record. Ryan McKellar added: “Amber pieces preserve tiny snapshots of ancient ecosystems, but they record microscopic details, three-dimensional arrangements, and labile tissues that are difficult to study in other settings.

“This is a new source of information that is worth researching with intensity, and protecting as a fossil resource.”

The researchers say they are now “eager to see how additional finds from this region will reshape our understanding of plumage and soft tissues in dinosaurs and other vertebrates.”

Paleontology: A monster put in its place

An analysis of the fossil known as the Minden Monster has enabled paleontologists to assign the largest predatory dinosaur ever found in Germany to a previously unknown genus, among a group that underwent rapid diversification in the Middle Jurassic.

This huge dinosaur dates to about 163 million years ago, in the Middle Jurassic. And it is not only the first carnivorous dinosaur from this period to be unearthed in Germany, it is also the largest ever found in the country: Based on the remains so far recovered, the specimen is estimated to have been between 8 and 10 meters in length. In comparison with other carnivorous dinosaurs, the animal was very sturdily built, weighed more than 2 tons — and was probably not fully grown when it died. Now Oliver Rauhut, a paleontologist in the Department of Earth and Environmental Sciences at LMU (who is also affiliated with the Bavarian State Collection for Paleontology and Geology in Munich), together with Tom Hübner and Klaus-Peter Lanser of the LWL Museum of Natural History in Münster, have undertaken a detailed study of the fossil material, and concluded that the specimen represents a previously unknown genus and species to which they have given the name Wiehenvenator albati.

Dinosaur archipelago

The first fossilized bones and teeth were discovered in 1999 during a routine surface survey in an abandoned quarry in the Wiehengebirge, a range of low hills south of Minden. Although the fossil clearly represents a terrestrial form, the remains were embedded in marine sediments. It is however known that, in the Middle Jurassic, large areas of what is now Central Europe lay below sea level, and the shallow waters of this sea were dotted with islands. These islands appear to have been the home of a broad spectrum of carnivorous dinosaurs, some of which reached very large sizes, Rauhut explains.

“Moreover, most of them belonged to the group known as the megalosaurids.” Wiehenvenator albati was a megalosaur and other representatives of the group have been found in France and England. In fact, the megalosaurids are the earliest large carnivorous dinosaurs we know of.

The remains of W. albati that have so far been discovered do not constitute a complete skeleton. The material is, however, very well preserved, and anatomical details can be clearly discerned which unequivocally prove that this individual not only represents a new species, but a new genus. Some of the teeth that have been found are as big as bananas, and have a recurved shape, pointing backwards into the pharynx. Like Allosaurus and the much younger Tyrannosaurus rex, W. albati was bipedal, standing on its hindlegs, while its forelimbs were much reduced in length.

A phylogenetic analysis of the morphology of the specimen revealed that Wiehenvenator can be assigned to a group of dinosaurs that underwent a rapid adaptive radiation during the Middle Jurassic, giving rise to a diverse array of species in a relatively short time. “Practically all the major groups of predatory dinosaurs originated during this period, including the tyrannosaurs — which, however, only gave rise to their really gigantic representatives some 80 million years later — and the first direct ancestors of the birds,” says Rauhut. This huge burst of speciation was probably made possible by the preceding extinction of a large proportion of the more primitive forms of predatory dinosaurs at the end of Lower Jurassic, which may in turn have been precipitated by a change in the climate due to widespread volcanic activity.

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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.

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.

When age matters: precise dating of ancient charcoal found near skull is helping reveal unique period in prehistory

A partial human skull unearthed in 2008 in northern Israel may hold some clues as to when and where humans and Neanderthals might have interbred. The key to addressing this, as well as other important issues, is precisely determining the age of the skull. A combination of dating methods, one of them performed by Dr. Elisabetta Boaretto, head of the Weizmann Institute’s D-REAMS (DANGOOR Research Accelerator Mass Spectrometry) laboratory, has made it possible to define the period of time that the cave was occupied and thus the skull’s age. The combined dating provides evidence that Homo sapiens and Homo neanderthalensis could have lived side by side in the area.

The Manot Cave, a natural limestone formation, had been sealed for some 15,000 years. It was discovered by a bulldozer clearing the land for development, and the first to find the partial skull, which was sitting on a ledge, were spelunkers exploring the newly-opened cave. Five excavation seasons uncovered a rich deposit, with stone tools and stratified occupation levels covering a period of time from at least 55,000 to 27,000 years ago.
Dating the skull presented a number of difficulties. “Because it was already removed from the layer where it was presumably deposited,” says Dr. Elisabetta Boaretto, “we had to look for clues to tell us where and when it belonged in the setting of the archaeological record in the cave.”
The age of the skull was first determined to be 54.7 thousand years old by a technique known as the uranium-thorium method, which was applied to the thin mineral deposit on the skull. But the estimated possible error in that type of method is plus or minus 5.5 thousand years. To obtain independent confirmation of the date, a different type of dating was required, e.g., radiocarbon dating.
To narrow down the possible range of the skull’s age and determine when the skull’s owner had lived in the cave, the archaeological team led by Prof. Israel Hershkovitz of Tel Aviv University, Dr. Ofer Marder of Ben Gurion University and Dr. Omry Barzilai of the Israel Antiquities Authority turned to Dr. Boaretto. She and her team participated in the excavation of the cave and applied radiocarbon dating to carefully selected charcoal remains, so that the whole cave, and thus the timing of human occupation, was mapped. The agreement between the two methods — carbon and uranium-thorium — provided the necessary support for the “correction” in the original uranium-thorium dating of the skull, which then helped fix the true age of the skull at around 55,000 years.
The date and shape of the Manot Cave skull provides some intriguing evidence that humans and Neanderthals might have interbred sometime during the human trek out of Africa, most likely as the former passed through the Middle East before spreading out north and east. The 55,000-year-old partial skull is the first evidence of a human residing in the region at the same time as Neanderthals, whose remains have been found at several nearby sites. Archaeologists are now searching for more evidence of ancient human habitation in the cave. If, indeed, the mixing between humans and Neanderthals took place in this area, it would suggest that the owner of the skull and his kin may have been the ancestors of all modern non-Africans.

International team of scientists launches fossil database

Have you ever wondered exactly when a certain group of plants or animals first evolved? This week a groundbreaking new resource for scientists will go live, and it is designed to help answer just those kinds of questions. The Fossil Calibration Database, a free, open-access resource that stores carefully vetted fossil data, is the result of years of work from a worldwide team led by Dr. Daniel Ksepka, Curator of Science at the Bruce Museum in Greenwich, and Dr. James Parham, Curator at the John D. Cooper Archaeological and Paleontological Center in Orange County, California, funded through the National Evolutionary Synthesis Center (NESCent).
“Fossils provide the critical age data we need to unlock the timing of major evolutionary events,” says Dr. Ksepka. “This new resource will provide the crucial fossil data needed to calibrate ‘molecular clocks’ which can reveal the ages of plant and animal groups that lack good fossil records. When did groups like songbirds, flowering plants, or sea turtles evolve? What natural events were occurring that may have had an impact? Precisely tuning the molecular clock with fossils is the best way we have to tell evolutionary time.”
More than twenty paleontologists, molecular biologists, and computer programmers from five different countries contributed to the design and implementation of this new database. The Fossil Calibrations Database webpage launches on Tuesday February 24th, and a series of five peer-reviewed papers and an editorial on the topic will appear in the scientific journal Palaeontologia Electronica, describing the endeavor. Dr. Ksepka is the author of one of the papers and co-author of the editorial.
“This exciting field of study, known as ‘divergence dating,’ is important for understanding the origin and evolution of biodiversity, but has been hindered by the improper use of data from the fossil record,” says Dr. Parham. “The Fossil Calibration Database addresses this issue by providing molecular biologists with paleontologist-approved data for organisms across the Tree of Life.”
The Tree of Life? “Think of it as a family tree of all species,” explains Dr. Ksepka.
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The above story is based on materials provided by Bruce Museum. Note: Materials may be edited for content and length.

Ancient rocks show life could have flourished on Earth 3.2 billion years ago

A spark from a lightning bolt, interstellar dust, or a subsea volcano could have triggered the very first life on Earth. But what happened next? Life can exist without oxygen, but without plentiful nitrogen to build genes — essential to viruses, bacteria and all other organisms — life on the early Earth would have been scarce.
The ability to use atmospheric nitrogen to support more widespread life was thought to have appeared roughly 2 billion years ago. Now research from the University of Washington looking at some of the planet’s oldest rocks finds evidence that 3.2 billion years ago, life was already pulling nitrogen out of the air and converting it into a form that could support larger communities.
“People always had the idea that the really ancient biosphere was just tenuously clinging on to this inhospitable planet, and it wasn’t until the emergence of nitrogen fixation that suddenly the biosphere become large and robust and diverse,” said co-author Roger Buick, a UW professor of Earth and space sciences. “Our work shows that there was no nitrogen crisis on the early Earth, and therefore it could have supported a fairly large and diverse biosphere.”
The results were published Feb. 16 in Nature.
The authors analyzed 52 samples ranging in age from 2.75 to 3.2 billion years old, collected in South Africa and northwestern Australia. These are some of the oldest and best-preserved rocks on the planet. The rocks were formed from sediment deposited on continental margins, so are free of chemical irregularities that would occur near a subsea volcano. They also formed before the atmosphere gained oxygen, roughly 2.3 to 2.4 billion years ago, and so preserve chemical clues that have disappeared in modern rocks.
Even the oldest samples, 3.2 billion years old — three-quarters of the way back to the birth of the planet — showed chemical evidence that life was pulling nitrogen out of the air. The ratio of heavier to lighter nitrogen atoms fits the pattern of nitrogen-fixing enzymes contained in single-celled organisms, and does not match any chemical reactions that occur in the absence of life.
“Imagining that this really complicated process is so old, and has operated in the same way for 3.2 billion years, I think is fascinating,” said lead author Eva Stüeken, who did the work as part of her UW doctoral research. “It suggests that these really complicated enzymes apparently formed really early, so maybe it’s not so difficult for these enzymes to evolve.”
Genetic analysis of nitrogen-fixing enzymes have placed their origin at between 1.5 and 2.2 billion years ago.
“This is hard evidence that pushes it back a further billion years,” Buick said. Fixing nitrogen means breaking a tenacious triple bond that holds nitrogen atoms in pairs in the atmosphere and joining a single nitrogen to a molecule that is easier for living things to use. The chemical signature of the rocks suggests that nitrogen was being broken by an enzyme based on molybdenum, the most common of the three types of nitrogen-fixing enzymes that exist now. Molybdenum is now abundant because oxygen reacts with rocks to wash it into the ocean, but its source on the ancient Earth — before the atmosphere contained oxygen to weather rocks — is more mysterious.
The authors hypothesize that this may be further evidence that some early life may have existed in single-celled layers on land, exhaling small amounts of oxygen that reacted with the rock to release molybdenum to the water.
“We’ll never find any direct evidence of land scum one cell thick, but this might be giving us indirect evidence that the land was inhabited,” Buick said. “Microbes could have crawled out of the ocean and lived in a slime layer on the rocks on land, even before 3.2 billion years ago.”
Future work will look at what else could have limited the growth of life on the early Earth. Stüeken has begun a UW postdoctoral position funded by NASA to look at trace metals such as zinc, copper and cobalt to see if one of them controlled the growth of ancient life.