Mysterious ‘Monster’ Discovered by Amateur Paleontologist

ScienceDaily (Apr. 24, 2012) — For 70 years, academic paleontologists have been assisted by a dedicated corps of amateurs known as the Dry Dredgers. Recently, one amateur found a very large and very mysterious fossil that has the professionals puzzled.

Around 450 million years ago, shallow seas covered the Cincinnati region and harbored one very large and now very mysterious organism. Despite its size, no one has ever found a fossil of this “monster” until its discovery by an amateur paleontologist last year.

The fossilized specimen, a roughly elliptical shape with multiple lobes, totaling almost seven feet in length, will be unveiled at the North-Central Section 46th Annual Meeting of the Geological Society of America, April 24, in Dayton, Ohio. Participating in the presentation will be amateur paleontologist Ron Fine of Dayton, who originally found the specimen, Carlton E. Brett and David L. Meyer of the University of Cincinnati geology department, and Benjamin Dattilo of the Indiana University Purdue University Fort Wayne geosciences faculty.

Fine is a member of the Dry Dredgers, an association of amateur paleontologists based at the University of Cincinnati. The club, celebrating its 70th anniversary this month, has a long history of collaborating with academic paleontologists.

“I knew right away that I had found an unusual fossil,” Fine said. “Imagine a saguaro cactus with flattened branches and horizontal stripes in place of the usual vertical stripes. That’s the best description I can give.”

The layer of rock in which he found the specimen near Covington, Kentucky, is known to produce a lot of nodules or concretions in a soft, clay-rich rock known as shale.

“While those nodules can take on some fascinating, sculpted forms, I could tell instantly that this was not one of them,” Fine said. “There was an ‘organic’ form to these shapes. They were streamlined.”

Fine was reminded of streamlined shapes of coral, sponges and seaweed as a result of growing in the presence of water currents.

“And then there was that surface texture,” Fine said. “Nodules do not have surface texture. They’re smooth. This fossil had an unusual texture on the entire surface.”

For more than 200 years, the rocks of the Cincinnati region have been among the most studied in all of paleontology, and the discovery of an unknown, and large, fossil has professional paleontologists scratching their heads.

“It’s definitely a new discovery,” Meyer said. “And we’re sure it’s biological. We just don’t know yet exactly what it is.”

To answer that key question, Meyer said that he, Brett, and Dattilo were working with Fine to reconstruct a timeline working backward from the fossil, through its preservation, burial, and death to its possible mode of life.

“What things had to happen in what order?” Meyer asked. “Something caused a directional pattern. How did that work? Was it there originally or is it post-mortem? What was the burial event? How did the sediment get inside? Those are the kinds of questions we have.”

It has helped, Meyer said, that Fine has painstakingly reassembled the entire fossil. This is a daunting task, since the large specimen is in hundreds of pieces.

“I’ve been fossil collecting for 39 years and never had a need to excavate. But this fossil just kept going, and going, and going,” Fine said. “I had to make 12 trips, over the course of the summer, to excavate more material before I finally found the end of it.”

Even then he still had to guess as to the full size, because it required countless hours of cleaning and reconstruction to put it all back together.

“When I finally finished it was three-and-a-half feet wide and six-and-a-half feet long,” Fine said. “In a world of thumb-sized fossils that’s gigantic!”

Meyer, co-author of A Sea without Fish: Life in the Ordovician Sea of the Cincinnati Region, agreed that it might be the largest fossil recovered from the Cincinnati area.

“My personal theory is that it stood upright, with branches reaching out in all directions similar to a shrub,” Fine said. “If I am right, then the upper-most branch would have towered nine feet high. “

As Meyer, Brett and Dattilo assist Fine in studying the specimen, they have found a clue to its life position in another fossil. The mystery fossil has several small, segmented animals known as primaspid trilobites attached to its lower surface. These small trilobites are sometimes found on the underside of other fossilized animals, where they were probably seeking shelter.

“A better understanding of that trilobite’s behavior will likely help us better understand this new fossil,” Fine said.

Although the team has reached out to other specialists, no one has been able to find any evidence of anything similar having been found. The mystery monster seems to defy all known groups of organisms, Fine said, and descriptions, even pictures, leave people with more questions than answers.

The presentation April 24 is a “trial balloon,” Meyer said, an opportunity for the team to show a wide array of paleontologists what the specimen looks like and to collect more hypotheses to explore.

“We hope to get a lot of people stopping by to offer suggestions,” he said.

In the meantime, the team is playing around with potential names. They are leaning toward “Godzillus.”

Egg-Laying Beginning of the End for Dinosaurs

ScienceDaily (Apr. 17, 2012) — Their reproductive strategy spelled the beginning of the end: The fact that dinosaurs laid eggs put them at a considerable disadvantage compared to viviparous mammals. Together with colleagues from the Zoological Society of London, Daryl Codron and Marcus Clauss from the University of Zurich investigated and published why and how this ultimately led to the extinction of the dinosaurs in the journal Biology Letters.

The dinosaur’s egg and the tiny dino baby

Weighing in at four tons, the mother animal was 2,500 times heavier than its newly hatched dinosaur baby. By way of comparison, a mother elephant, which is just as heavy, only weighs 22 times as much as its new-born calf. In other words, neonates are already big in large mammal species. The staggering difference in size between newly hatched dinosaurs and their parents was down to the fact that there are limits to the size eggs can become: After all, larger eggs require a thicker shell and as the embryo also needs to be supplied with oxygen through this shell, eventually neither the shell nor the egg can grow any more. Consequently, newly hatched dinosaur babies cannot be larger in the same way as in larger species of mammal.

Many species occupy one niche each; one species occupies many niches

In addition, new-born mammals occupy the same ecological niche as their parents: As they are fed with milk directly by the mother, they do not take any niche away from smaller species. With large dinosaurs, however, it was an entirely different story: They did not only occupy the adults’ one niche during their lifetime, but also had many of their own to pass through — from niches for animals with a body size of a few kilos and those for ten, 100 and 1,000-kilo animals to those that were occupied by the fully grown forms of over 30,000 kilograms.

Daryl Codron explains what this means for biodiversity: “The consensus among researchers is that animals of particular body sizes occupy particular niches. In the case of the dinosaurs, this would mean that a single species occupied the majority of the ecological niches while mammals occupied these through numerous species of different sizes.” Accordingly, the research results reveal that dinosaurs of a small and medium body size were represented with far fewer individual species than was the case in mammals — because their niches were occupied by the young of larger species.

“An overview of the body sizes of all dinosaur species — including those of birds, which are also dinosaurs after all — reveals that few species existed with adults weighing between two and sixty kilograms,” specifies Codron. And Marcus Clauss sums up the consequences of this demonstrated by the researchers using computer simulations: “Firstly, this absence of small and medium-sized species was due to the competition among the dinosaurs; in mammals, there was no such gap. Secondly, in the presence of large dinosaurs and the ubiquitous competition from their young, mammals did not develop large species themselves.” The third insight that the computer simulation illustrates concerns small dinosaurs: They were in competition both among their own ranks and with small mammals. And this increased pressure brought the small dinosaurs either to the brink of extinction or forced them to conquer new niches. The latter enabled them to guarantee their survival up to the present day, as Codron concludes, since “back then, they had to take to the air as birds.”

Catastrophe: Small dinosaurs take to the air and large ones die out

The dinosaurs’ supremacy as the largest land animals remained intact for 150 million years. The mass extinction at the Cretaceous-Tertiary boundary, however, spelled trouble as the species gap in the medium size range turned out to be disastrous for them. According to the current level of knowledge, all the larger animals with a body weight from approximately ten to 25 kilos died out. Mammals had many species below this threshold, from which larger species were able to develop after the calamity and occupy the empty niches again. The dinosaurs, however, lacked the species that would have been able to reoccupy the vacant niches. That was their undoing.

Evidence for a Geologic Trigger of the Cambrian Explosion

ScienceDaily (Apr. 18, 2012) — The oceans teemed with life 600 million years ago, but the simple, soft-bodied creatures would have been hardly recognizable as the ancestors of nearly all animals on Earth today.

Then something happened. Over several tens of millions of years — a relative blink of an eye in geologic terms — a burst of evolution led to a flurry of diversification and increasing complexity, including the expansion of multicellular organisms and the appearance of the first shells and skeletons.

The results of this Cambrian explosion are well documented in the fossil record, but its cause — why and when it happened, and perhaps why nothing similar has happened since — has been a mystery.

New research shows that the answer may lie in a second geological curiosity — a dramatic boundary, known as the Great Unconformity, between ancient igneous and metamorphic rocks and younger sediments.

“The Great Unconformity is a very prominent geomorphic surface and there’s nothing else like it in the entire rock record,” says Shanan Peters, a geoscience professor at the University of Wisconsin-Madison who led the new work. Occurring worldwide, the Great Unconformity juxtaposes old rocks, formed billions of years ago deep within Earth’s crust, with relatively young Cambrian sedimentary rock formed from deposits left by shallow ancient seas that covered the continents just a half billion years ago.

Named in 1869 by explorer and geologist John Wesley Powell during the first documented trip through the Grand Canyon, the Great Unconformity has posed a longstanding puzzle and has been viewed — by Charles Darwin, among others — as a huge gap in the rock record and in our understanding of Earth’s history.

But Peters says the gap itself — the missing time in the geologic record — may hold the key to understanding what happened.

In the April 19 issue of the journal Nature, he and colleague Robert Gaines of Pomona College report that the same geological forces that formed the Great Unconformity may have also provided the impetus for the burst of biodiversity during the early Cambrian.

“The magnitude of the unconformity is without rival in the rock record,” Gaines says. “When we pieced that together, we realized that its formation must have had profound implications for ocean chemistry at the time when complex life was just proliferating.”

“We’re proposing a triggering mechanism for the Cambrian explosion,” says Peters. “Our hypothesis is that biomineralization evolved as a biogeochemical response to an increased influx of continental weathering products during the last stages in the formation of the Great Unconformity.”

Peters and Gaines looked at data from more than 20,000 rock samples from across North America and found multiple clues, such as unusual mineral deposits with distinct geochemistry, that point to a link between the physical, chemical, and biological effects.

During the early Cambrian, shallow seas repeatedly advanced and retreated across the North American continent, gradually eroding away surface rock to uncover fresh basement rock from within the crust. Exposed to the surface environment for the first time, those crustal rocks reacted with air and water in a chemical weathering process that released ions such as calcium, iron, potassium, and silica into the oceans, changing the seawater chemistry.

The basement rocks were later covered with sedimentary deposits from those Cambrian seas, creating the boundary now recognized as the Great Unconformity.

Evidence of changes in the seawater chemistry is captured in the rock record by high rates of carbonate mineral formation early in the Cambrian, as well as the occurrence of extensive beds of glauconite, a potassium-, silica-, and iron-rich mineral that is much rarer today.

The influx of ions to the oceans also likely posed a challenge to the organisms living there. “Your body has to keep a balance of these ions in order to function properly,” Peters explains. “If you have too much of one you have to get rid of it, and one way to get rid of it is to make a mineral.”

The fossil record shows that the three major biominerals — calcium phosphate, now found in bones and teeth; calcium carbonate, in invertebrate shells; and silicon dioxide, in radiolarians — appeared more or less simultaneously around this time and in a diverse array of distantly related organisms.

The time lag between the first appearance of animals and their subsequent acquisition of biominerals in the Cambrian is notable, Peters says. “It’s likely biomineralization didn’t evolve for something, it evolved in response to something — in this case, changing seawater chemistry during the formation of the Great Unconformity. Then once that happened, evolution took it in another direction.” Today those biominerals play essential roles as varied as protection (shells and spines), stability (bones), and predation (teeth and claws).

Together, the results suggest that the formation of the Great Unconformity may have triggered the Cambrian explosion.

“This feature explains a lot of lingering questions in different arenas, including the odd occurrences of many types of sedimentary rocks and a very remarkable style of fossil preservation. And we can’t help but think this was very influential for early developing life at the time,” Gaines says.

Far from being a lack of information, as Darwin thought, the gaps in the rock record may actually record the mechanism as to why the Cambrian explosion occurred in the first place, Peters says.

“The French composer Claude Debussy said, ‘Music is the space between the notes.’ I think that is the case here,” he says. “The gaps can have more information, in some ways, about the processes driving Earth system change, than the rocks do. It’s both together that give the whole picture.”

The work was supported by the National Science Foundation

Duck-Billed Dinosaurs Endured Long, Dark Polar Winters

ScienceDaily (Apr. 11, 2012) — Duck-billed dinosaurs that lived within Arctic latitudes approximately 70 million years ago likely endured long, dark polar winters instead of migrating to more southern latitudes, a recent study by researchers from the University of Cape Town, Museum of Nature and Science in Dallas and Temple University has found.

The researchers published their findings, “Hadrosaurs Were Perennial Polar Residents,” in the April issue of the journal The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology.

Anthony Fiorillo, a paleontologist at the Museum of Nature and Science, excavated Cretaceous Period fossils along Alaska’s North Slope. Most of the bones belonged to Edmontosaurus, a duck-billed herbivore, but some others such as the horned dinosaur Pachyrhinosaurus were also found.

Fiorillo hypothesized that the microscopic structures of the dinosaurs’ bones could show how they lived in polar regions. He enlisted the help of Allison Tumarkin-Deratzian, an assistant professor of earth and environmental science, who had both expertise and the facilities to create and analyze thin layers of the dinosaurs’ bone microstructure.

Another researcher, Anusuya Chinsamy-Turan, a professor of zoology at the University of Cape Town, was independently pursuing the same analysis of Alaskan Edmontosaurus fossils. When the research groups discovered the similarities of their studies, they decided to collaborate and combine their data sets to provide a larger sampling. Half of the samples were tested and analyzed at Temple; the rest were done in South Africa.

“The bone microstructure of these dinosaurs is actually a record of how these animals were growing throughout their lives,” said Tumarkin-Deratzian. “It is almost similar to looking at tree rings.”

What the researchers found was bands of fast growth and slower growth that seemed to indicate a pattern.

“What we found was that periodically, throughout their life, these dinosaurs were switching how fast they were growing,” said Tumarkin-Deratzian. “We interpreted this as potentially a seasonal pattern because we know in modern animals these types of shifts can be induced by changes in nutrition. But that shift is often driven by changes in seasonality.”

The researchers questioned what was causing the dinosaurs to be under stress at certain times during the year: staying up in the polar region and dealing with reduced nutrition during the winter or migrating to and from lower latitudes during the winter.

They did bone microstructure analysis on similar duck-billed dinosaur fossils found in southern Alberta, Canada, but didn’t see similar stress patterns, implying that those dinosaurs did not experience regular periodic seasonal stresses. “We had two sets of animals that were growing differently,” said Tumarkin-Deratzian.

Since the Alaska fossils had all been preserved in the same sedimentary horizon, Fiorillo examined the geology of the bonebeds in Alaska where the samples were excavated and discovered that these dinosaurs had been preserved in flood deposits.

“They are very similar to modern flood deposits that happen in Alaska in the spring when you get spring melt water coming off the Brooks Mountain Range,” said Fiorillo. “The rivers flood down the Northern Slope and animals get caught in these floods, particularly younger animals, which appear to be what happened to these dinosaurs.

“So we know they were there at the end of the dark winter period, because if they were migrating up from the lower latitudes, they wouldn’t have been there during these floods,” he said.

“It is fascinating to realize how much of information is locked in the bone microstructure of fossil bones,” said Chinsamy-Turan. “It’s incredible to realize that we can also tell from these 70 million-year-old bones that the majority of the polar hadrosaurs died just after the winter season.”

The study was funded through a grant from the National Science Foundation.