Rukwatitan bisepultus : new species of titanosaurian

Ohio University paleontologists have identified a new species of titanosaurian, a member of the large-bodied sauropods that thrived during the final period of the dinosaur age, in Tanzania. Although many fossils of titanosaurians have been discovered around the globe, especially in South America, few have been recovered from the continent of Africa.

The new species, named Rukwatitan bisepultus, was first spotted by scientists embedded in a cliff wall in the Rukwa Rift Basin of southwestern Tanzania. Using the help of professional excavators and coal miners, the team unearthed vertebrae, ribs, limbs and pelvic bones over the course of two field seasons.

An artistic rendering of a deceased Rukwatitan bisepultus individual in the initial floodplain depositional setting from which the holotypic skeleton was recovered. Credit: Mark Witton, University of Portsmouth

An artistic rendering of a deceased Rukwatitan bisepultus individual in the initial floodplain depositional setting from which the holotypic skeleton was recovered.
Credit: Mark Witton, University of Portsmouth

CT scans of the fossils, combined with detailed comparisons with other sauropods, revealed unique features that suggested an animal that was different from previous finds — including those from elsewhere in Africa, according to a study the team published today in the Journal of Vertebrate Paleontology.

“Using both traditional and new computational approaches, we were able to place the new species within the family tree of sauropod dinosaurs and determine both its uniqueness as a species and to delineate others species with which it is most closely related,” said lead author Eric Gorscak, a doctoral student in biological sciences at Ohio University.

Rukwatitan bisepultus lived approximately 100 million years ago during the middle of the Cretaceous Period. Titanosaurian sauropods, the group that includes Rukwatitan, were herbivorous dinosaurs known for their iconic large body sizes, long necks and wide stance. Although not among the largest of titanosaurians, Rukwatitan is estimated to have a forelimb reaching 2 meters and may have weighed as much as several elephants.

The dinosaur’s bones exhibit similarities with another titanosaurian, Malawisaurus dixeyi, previously recovered in Malawi. But the two southern African dinosaurs are distinctly different from one another, and, most notably, from titanosaurians known from northern Africa, said co-author Patrick O’Connor, a professor of anatomy in the Ohio University Heritage College of Osteopathic Medicine.

The fossils of middle Cretaceous crocodile relatives from the Rukwa Rift Basin also exhibit distinctive features when compared to forms from elsewhere on the continent.

“There may have been certain environmental features, such as deserts, large waterways and/or mountain ranges, that would have limited the movement of animals and promoted the evolution of regionally distinct faunas,” O’Connor said. “Only additional data on the faunas and paleo environments from around the continent will let us further test such hypotheses.”

In addition to providing new data about species evolution in sub-Saharan Africa, the study also contributes to fleshing out the global portrait of titanosaurians, which lived in habitats across the globe through the end of the Cretaceous Period. Their rise in diversity came in the wake of the decline of another group of sauropods, the diplodocoids, which include the dinosaur Apatosaurus, the researchers noted. Scientists have found fossils for more than 30 titanosaurians in South America compared to just four in Africa.

“Much of what we know regarding titanosaurian evolutionary history stems from numerous discoveries in South America — a continent that underwent a steady separation from Africa during the first half of the Cretaceous Period,” Gorscak said. “With the discovery of Rukwatitan and study of the material in nearby Malawi, we are beginning to fill a significant gap from a large part of the world.”

Co-authors on the study are Nancy Stevens, a professor in the Ohio University Heritage College of Osteopathic Medicine, and Eric Roberts, a senior lecturer in the James Cook University of Australia.

The study was funded by the National Science Foundation, the National Geographic Society, the Ohio University Heritage College of Osteopathic Medicine and the Ohio University Office of the Vice President for Research and Creative Activity.

Scientists report first semiaquatic dinosaur, Spinosaurus: Massive predator was more than 9 feet longer than largest T. rex

Scientists are unveiling what appears to be the first truly semiaquatic dinosaur, Spinosaurus aegyptiacus. New fossils of the massive Cretaceous-era predator reveal it adapted to life in the water some 95 million years ago, providing the most compelling evidence to date of a dinosaur able to live and hunt in an aquatic environment. The fossils also indicate that Spinosaurus was the largest known predatory dinosaur to roam Earth, measuring more than nine feet longer than the world’s largest Tyrannosaurus rex specimen.

These findings, to be published Sept. 11 in the journal Science online at the Science Express website, are also featured in the October National Geographic magazine cover story available online Sept. 11. In addition, Spinosaurus will be the subject of a new exhibition at the National Geographic Museum, opening Sept. 12, as well as a National Geographic/NOVA special airing on PBS Nov. 5 at 9 p.m.

An international research team — including paleontologists Nizar Ibrahim and Paul Sereno from the University of Chicago; Cristiano Dal Sasso and Simone Maganuco from the Natural History Museum in Milan, Italy; and Samir Zouhri from the Université Hassan II Casablanca in Morocco — found that Spinosaurus developed a variety of previously unknown aquatic adaptations.

The researchers came to their conclusions after analyzing new fossils uncovered in the Moroccan Sahara and a partial Spinosaurus skull and other remains housed in museum collections around the world as well as historical records and images from the first reported Spinosaurus discovery in Egypt more than 100 years ago. According to lead author Ibrahim, a 2014 National Geographic Emerging Explorer, “Working on this animal was like studying an alien from outer space; it’s unlike any other dinosaur I have ever seen.”

The aquatic adaptations of Spinosaurus differ significantly from earlier members of the spinosaurid family that lived on land but were known to eat fish. These adaptations include:

  • Small nostrils located in the middle of the skull. The small size and placement of the nostrils farther back on the skull allowed Spinosaurus to breathe when part of its head was in water.
  • Neurovascular openings at the end of the snout. Similar openings on crocodile and alligator snouts contain pressure receptors that enable them to sense movement in water. It’s likely these openings served a comparable function in Spinosaurus.
  • Giant, slanted teeth that interlocked at the front of the snout. The conical shape and location of the teeth were well-suited for catching fish.
  • A long neck and trunk that shifted the dinosaur’s center of mass forward. This made walking on two legs on land nearly impossible, but facilitated movement in water.
  • Powerful forelimbs with curved, blade-like claws. These claws were ideal for hooking or slicing slippery prey.
  • A small pelvis and short hind legs with muscular thighs. As in the earliest whales, these adaptations were for paddling in water and differ markedly from other predatory dinosaurs that used two legs to move on land.
  • Particularly dense bones lacking the marrow cavities typical to predatory dinosaurs. Similar adaptations, which enable buoyancy control, are seen in modern aquatic animals like king penguins.
  • Strong, long-boned feet and long, flat claws. Unlike other predators, Spinosaurus had feet similar to some shorebirds that stand on or move across soft surfaces rather than perch. In fact, Spinosaurus may have had webbed feet for walking on soft mud or paddling.
  • Loosely connected bones in the dinosaur’s tail. These bones enabled its tail to bend in a wave-like fashion, similar to tails that help propel some bony fish.
  • Enormous dorsal spines covered in skin that created a gigantic “sail” on the dinosaur’s back. The tall, thin, blade-shaped spines were anchored by muscles and composed of dense bone with few blood vessels. This suggests the sail was meant for display and not to trap heat or store fat. The sail would have been visible even when the animal entered the water.

More than a century ago, German paleontologist Ernst Freiherr Stromer von Reichenbach first discovered evidence of Spinosaurus in the Egyptian Sahara. Sadly, all of Stromer’s fossils were destroyed during the April 1944 Allied bombing of Munich, Germany. Ibrahim, however, was able to track down Stromer’s surviving notes, sketches and photos in archives and at the Stromer family castle in Bavaria to supplement Stromer’s surviving publications.

The new Spinosaurus fossils were discovered in the Moroccan Sahara along desert cliffs known as the Kem Kem beds. This area was once a large river system, stretching from present-day Morocco to Egypt. At the time, a variety of aquatic life populated the system, including large sharks, coelacanths, lungfish and crocodile-like creatures, along with giant flying reptiles and predatory dinosaurs.

The most important of the new fossils, a partial skeleton uncovered by a local fossil hunter, was spirited out of the country. As a result, critical information about the context of the find was seemingly lost, and locating the local fossil hunter in Morocco was nearly impossible. Remarked Ibrahim, “It was like searching for a needle in a desert.” After an exhaustive search, Ibrahim finally found the man and confirmed the site of his original discovery.

To unlock the mysteries of Spinosaurus, the team created a digital model of the skeleton with funding provided by the National Geographic Society. The researchers CT scanned all of the new fossils, which will be repatriated to Morocco, complementing them with digital recreations of Stromer’s specimens. Missing bones were modeled based on known elements of related dinosaurs.

According to Maganuco, “We relied upon cutting-edge technology to examine, analyze and piece together a variety of fossils. For a project of this complexity, traditional methods wouldn’t have been nearly as accurate.”

The researchers then used the digital model to create an anatomically precise, life-size 3-D replica of the Spinosaurus skeleton. After it was mounted, the researchers measured Spinosaurus from head to tail, confirming their calculation that the new skeleton was longer than the largest documented Tyrannosaurus by more than 9 feet.

According to Sereno, head of the University of Chicago’s Fossil Lab, “What surprised us even more than the dinosaur’s size were its unusual proportions. We see limb proportions like this in early whales, not predatory dinosaurs.”

Added Dal Sasso, “In the last two decades, several finds demonstrated that certain dinosaurs gave origins to birds. Spinosaurus represents an equally bizarre evolutionary process, revealing that predatory dinosaurs adapted to a semiaquatic life and invaded river systems in Cretaceous North Africa.”

The life-size skeletal replica will be the centerpiece of a new exhibition at the National Geographic Museum in Washington, D.C., titled “Spinosaurus: Lost Giant of the Cretaceous.” The exhibition, which runs from Sept. 12, 2014, to April 12, 2015, brings to life the story of Spinosaurus, from Stromer’s original discoveries to the dedicated efforts of the international research team working to unlock its secrets.

For more information on this interactive, multimedia experience developed in collaboration with UChicagoTech, the university’s Center for Technology Development & Ventures, visit ngmuseum.org.

The global search to uncover the Spinosaurus skeleton and its mysteries will also be featured in a National Geographic/NOVA special, “Bigger Than T.rex,” airing on PBS Nov. 5, 2014, at 9 p.m.

Other authors of the Science paper are David Martill, University of Portsmouth, United Kingdom; Matteo Fabbri, University of Bristol, United Kingdom; Nathan Myhrvold, Intellectual Ventures; and Dawid Iurino, Sapienza Università di Roma in Italy. Important contributors to the making of the digital Spinosaurus include Tyler Keillor, Lauren Conroy and Erin Fitzgerald of the Fossil Lab at the University of Chicago.

Mantle plumes crack continents

In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth’s core and the lower mantle to just below Earth’s crust hundreds of kilometres above. Halted by the resistance of the hard crust and lithospheric mantle, the flow of material becomes wider, taking on a mushroom-like shape. Specialists call these magma columns “mantle plumes” or simply “plumes.”

In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth's core and the lower mantle to just below Earth's crust hundreds of kilometres above. Credit: "Lower Mantle Superplume" by Brews ohare - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Lower_Mantle_Superplume.PNG#mediaviewer/File:Lower_Mantle_Superplume.PNG

In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth’s core and the lower mantle to just below Earth’s crust hundreds of kilometres above.

Are mantle plumes responsible for the African rift system?

Geologists believe that plumes are not just responsible for creating volcanoes outside of tectonically active areas — they can also break up continents. The scientists offer the Danakil Depression (the lowlands in the Ethiopia-Eritrea-Djibouti triangle) as an example of this. This “triple junction” is extremely tectonically and volcanically active. Geologists believe that the so-called Afar plume is rising up below it and has created a rift system that forks into the Red Sea, the Gulf of Aden and Africa’s Great Rift Valley. However, the sheer length of time required, geologically speaking, for this process to take place, means that nobody is able to confirm or disprove with absolute certainty that the force of a plume causes continental breakup.

Simulations becoming more realistic

Evgueni Burov, a Professor at the University of Paris VI, and Taras Gerya, Professor of Geophysics at ETH Zurich, have now taken a step closer to solving this geological mystery with a new computer model. Their paper has recently been published in the journal Nature. The two researchers conducted numerical experiments to reproduce the Earth’s surface in high-resolution 3D.

These simulations show that the rising flow of material is strong enough to cause continental breakup if the tectonic plate is under (weak) tensile stress. “The force exerted by a plume on a plate is actually too weak to break it up,” says Gerya. In experiments using simple models, the researchers allowed the plumes to hit an unstressed plate, which did not cause it to break, but merely formed a round hump. However, when the geophysicists modelled the same process with a plate under weak tensile stress, it broke apart, forming a crevice and rift system like the ones found around the world.

“The process can be compared to a taut piece of plastic film. Weak, pointed force is enough to tear the film, but if the film is not pulled taut, it is extremely difficult to tear.” This mechanism has already been proposed in the past as a possible model for explaining continental breakup, but had never been outlined in plausible terms before now.

First high-resolution simulations

“We are the first to create such a high-resolution model which demonstrates how a plume interacts with a plate under tensile stress,” says Gerya. Fast and powerful computers and stable algorithms programmed by the scientists themselves were required for the simulations. The researchers benefited from technical advances made and experience accumulated by the ETH professor in this field over the past ten years.

In the model, the deformations are created quickly from a geological point of view. Rift systems several kilometres deep and more than a thousand kilometres long can form after “just” two million years. The processes are therefore up to ten times faster than tectonic processes such as subduction and 50 times faster than the Alpine orogeny, for example.

Disputed idea

The idea of mantle plumes is widely disputed, with some researchers denying that they even exist. “I think it is much more likely that they do exist,” says Gerya. As is often the case in geology, especially when researching Earth’s interior, such processes and phenomena like the existence of plumes cannot be observed directly. Furthermore, the periods over which geological processes take place are far too long for humans to experience first-hand. “So far, we have only been able to observe the effects that plumes have on the Earth’s surface and on the propagation of seismic waves in the Earth’s interior.”

The scientists are therefore reliant on good, realistic models that show the processes in a geological time lapse. How realistic the calculated simulations are depends on the parameters used. The plume-plate interaction model incorporated physical laws, the characteristics of materials in the Earth’s crust and mantle, and temperature and pressure conditions. “We know the rules, but humans generally lack the intuition to identify how they interact on geological timescales.”

How good is the fossil record?

Methods have been developed to try to identify and correct for bias in the fossil record but new research from the Universities of Bristol and Bath, suggests many of these correction methods may actually be misleading.

The study, led by Dr Alex Dunhill, formerly at the Universities of Bristol and Bath and now at the University of Leeds, explored the rich and well-studied fossil record of Great Britain. Professional geological work has been done in the British Isles for over 200 years and the British Geological Survey (dating from the 1830s) has amassed enormous, detailed knowledge of every inch of the rocks and fossils of the islands.

A map showing the geology of Great Britain spanning the past 550 million years. Credit: Dr Alex Dunhill

A map showing the geology of Great Britain spanning the past 550 million years.
Credit: Dr Alex Dunhill

Together with collaborators from the Universities of Bristol and Bergen, Dr Dunhill compared biodiversity through the last 550 million years of the British fossil record against a number of geological and environmental factors including the area of sedimentary rock, the number of recorded fossil collections and the number of named geological ‘formations’. All of these measures have been used as yardsticks against which the quality of the fossil record can be assessed — but the new study casts doubt on their usefulness.

Dr Dunhill said: “We suspected that the similar patterns displayed by the rock and fossil records were due to external factors rather than the number of fossils being simply dictated by the amount of accessible rock. Our work shows this is true. Factors such as counts of geological formations and collections cannot be used to correct biodiversity in the fossil record.”

The study benefits from the application of advanced mathematical techniques that not only identify whether two data sets correlate, but also whether one drives the other.

The results show that out of all the geological factors, only the area of preserved rock drives biodiversity. Therefore, the other geological factors — counts of fossil collections and geological formations — are not independent measures of bias in the fossil record.

Co-author, Bjarte Hannisdal from the University of Bergen, said: “We can learn more by analysing old data in new ways, than by analysing new data in old ways.”

This discovery fundamentally alters the way we view the diversity of life through time. It shows that both the preservation of rock and the preservation of fossils were probably driven by external environmental factors like climate change and sea level. This better explains the similarities between the rock and fossil records, as both responding to the same external factors. The alternative idea, that rock preservation was driving the fossil record is now strongly queried by this study. Perhaps the record of biodiversity in the fossil record is more accurate than previously feared.

Professor Michael Benton from the University of Bristol, another co-author of the study, said: “Palaeontologists are right to be cautious about the quality of the fossil record, but perhaps some have been too cautious. The sequence of fossils in the rocks more or less tells us the story of the history of life, and we have sensible ways of dealing with uncertainty. Some recent work on ‘correcting’ the fossil record by using formation counts may produce nonsense results.”

The research is published in Nature Communications.

Dreadnoughtus: Gigantic complete sauropod

Scientists have discovered and described a new supermassive dinosaur species with the most complete skeleton ever found of its type. At 85 feet (26 m) long and weighing about 65 tons (59,300 kg) in life, Dreadnoughtus schrani is the largest land animal for which a body mass can be accurately calculated. Its skeleton is exceptionally complete, with over 70 percent of the bones, excluding the head, represented. Because all previously discovered supermassive dinosaurs are known only from relatively fragmentary remains, Dreadnoughtus offers an unprecedented window into the anatomy and biomechanics of the largest animals to ever walk the Earth.

Dreadnoughtus schrani was astoundingly huge,” said Kenneth Lacovara, PhD, an associate professor in Drexel University’s College of Arts and Sciences, who discovered the Dreadnoughtus fossil skeleton in southern Patagonia in Argentina and led the excavation and analysis. “It weighed as much as a dozen African elephants or more than seven T. rex. Shockingly, skeletal evidence shows that when this 65-ton specimen died, it was not yet full grown. It is by far the best example we have of any of the most giant creatures to ever walk the planet.”

A US-Argentinian team led by Drexel University's Kenneth Lacovara, PhD, excavated the skeleton of Dreadnoughtus schrani from southern Patagonia over four field seasons from 2005 through 2009. The completeness and articulated nature of the two skeletons they found are evidence that these individuals were buried in sediments rapidly before their bodies fully decomposed. Credit: Kenneth Lacovara

A US-Argentinian team led by Drexel University’s Kenneth Lacovara, PhD, excavated the skeleton of Dreadnoughtus schrani from southern Patagonia over four field seasons from 2005 through 2009. The completeness and articulated nature of the two skeletons they found are evidence that these individuals were buried in sediments rapidly before their bodies fully decomposed.
Credit: Kenneth Lacovara

Lacovara and colleagues published the detailed description of their discovery, defining the genus and species Dreadnoughtus schrani, in the journal Scientific Reports from the Nature Publishing Group today. The new dinosaur belongs to a group of large plant eaters known as titanosaurs. The fossil was unearthed over four field seasons from 2005 through 2009 by Lacovara and a team including Lucio M. Ibiricu, PhD, of the Centro Nacional Patagonico in Chubut, Argentina, the Carnegie Museum of Natural History’s Matthew Lamanna, PhD, and Jason Poole of the Academy of Natural Sciences of Drexel University, as well as many current and former Drexel students and other collaborators.

Over 100 elements of the Dreadnoughtus skeleton are represented from the type specimen, including most of the vertebrae from the 30-foot-long tail, a neck vertebra with a diameter of over a yard, scapula, numerous ribs, toes, a claw, a small section of jaw and a single tooth, and, most notably for calculating the animal’s mass, nearly all the bones from both forelimbs and hindlimbs including a femur over 6 feet tall and a humerus. A smaller individual with a less-complete skeleton was also unearthed at the site.

The ‘gold standard’ for calculating the mass of quadrupeds (four-legged animals) is based on measurements taken from the femur (thigh bone) and humerus (upper arm bone). Because the Dreadnoughtus type specimen includes both these bones, its weight can be estimated with confidence. Prior to the description of the 65-ton Dreadnoughtus schrani specimen, another Patagonian giant, Elaltitan, held the title of dinosaur with the greatest calculable weight at 47 tons, based on a recent study.

Overall, the Dreadnoughtus schrani type specimen’s bones represent approximately 45.3 percent of the dinosaur’s total skeleton, or up to 70.4 percent of the types of bones in its body, excluding the skull bones. This is far more complete than all previously discovered giant titanosaurian dinosaurs.

“Titanosaurs are a remarkable group of dinosaurs, with species ranging from the weight of a cow to the weight of a sperm whale or more. But the biggest titanosaurs have remained a mystery, because, in almost all cases, their fossils are very incomplete,” said Matthew Lamanna.

For example, Argentinosaurus was of a comparable and perhaps greater mass than Dreadnoughtus, but is known from only a half dozen vertebrae in its mid-back, a shinbone and a few other fragmentary pieces; because the specimen lacks upper limb bones, there is no reliable method to calculate a definitive mass of Argentinosaurus. Futalognkosaurus was the most complete extremely massive titanosaur known prior to Dreadnoughtus, but that specimen lacks most limb bones, a tail and any part of its skull.

To better visualize the skeletal structure of Dreadnoughtus, Lacovara’s team digitally scanned all of the bones from both dinosaur specimens. They have made a “virtual mount” of the skeleton that is now publicly available for download from the paper’s open-access online supplement as a three-dimensional digital reconstruction.

“This has the advantage that it doesn’t take physical space,” Lacovara said. “These images can be ported around the world to other scientists and museums. The fidelity is perfect. It doesn’t decay over time like bones do in a collection.”

“Digital modeling is the wave of the future. It’s only going to become more common in paleontology, especially for studies of giant dinosaurs such as Dreadnoughtus, where a single bone can weigh hundreds of pounds,” said Lamanna.

The 3D laser scans of Dreadnoughtus show the deep, exquisitely preserved muscle attachment scars that can provide a wealth of information about the function and force of muscles that the animal had and where they attached to the skeleton — information that is lacking in many sauropods. Efforts to understand this dinosaur’s body structure, growth rate, and biomechanics are ongoing areas of research within Lacovara’s lab.

A Dinosaur that Feared Nothing

“With a body the size of a house, the weight of a herd of elephants, and a weaponized tail, Dreadnoughtus would have feared nothing,” Lacovara said. “That evokes to me a class of turn-of-the-last century battleships called the dreadnoughts, which were huge, thickly clad and virtually impervious.”

As a result, Lacovara chose the name “Dreadnoughtus,” meaning “fears nothing.” “I think it’s time the herbivores get their due for being the toughest creatures in an environment,” he said. The species name, “schrani,” was chosen in honor of American entrepreneur Adam Schran, who provided support for the research.

To grow as large as Dreadnoughtus, a dinosaur would have to eat massive quantities of plants. “Imagine a life-long obsession with eating,” Lacovara said, describing the potential lifestyle of Dreadnoughtus, which lived approximately 77 million years ago in a temperate forest at the southern tip of South America.

“Every day is about taking in enough calories to nourish this house-sized body. I imagine their day consists largely of standing in one place,” Lacovara said. “You have this 37-foot-long neck balanced by a 30-foot-long tail in the back. Without moving your legs, you have access to a giant feeding envelope of trees and fern leaves. You spend an hour or so clearing out this patch that has thousands of calories in it, and then you take three steps over to the right and spend the next hour clearing out that patch.”

An adult Dreadnoughtus was likely too large to fear any predators, but it would have still been a target for scavengers after dying of natural causes or environmental disasters. Lacovara’s team discovered a few teeth from theropods — smaller predatory and scavenging dinosaurs- among the Dreadnoughtus fossils. However, the completeness and articulated nature of the two skeletons are evidence that these individuals were buried in sediments rapidly before their bodies fully decomposed. Based on the sedimentary deposits at the site, Lacovara said “these two animals were buried quickly after a river flooded and broke through its natural levee, turning the ground into something like quicksand. The rapid and deep burial of the Dreadnoughtus type specimen accounts for its extraordinary completeness. Its misfortune was our luck.”

Gallomesovelia grioti: Well Preserved Fossil Insect

In Bavaria, the Tithonian Konservat-Lagerstätte of lithographic limestone is well known as a result of numerous discoveries of emblematic fossils from that area (for example, Archaeopteryx). Now, for the first time, researchers have found fossil insects in the French equivalent of these outcrops — discoveries which include a new species representing the oldest known water treader.

Despite the abundance of fossils in the equivalent Bavarian outcrops, fewer fossils have been obtained from the Late Kimmeridgian equivalents of these rocks in the departments of Ain and Rhône in France. Many outcrops are recorded (for example Cerin and Orbagnoux), but the fauna found there is essentially of marine origin, being made up of crustaceans and fishes. Some layers have provided dinosaur footprints, but until today’s announcement the only known terrestrial organisms were plant remains transported into the ancient lagoons.

During the course of two field expeditions in 2012 and 2013 French researchers working with the help of two active teams of amateur scientists (Société des Naturalistes et Archéologues de l’Ain and the Group ‘Sympetrum Recherche et Protection des Libellules’) discovered the first insects from the Orbagnoux outcrop, together with traces of activities of these organisms on leaves and in the sediment.

This is a fossilized aquatic bug from the Orbagnoux outcrop of the Rhone valey: Gallomesovelia grioti (scale bar 1 mm). Credit: Nel Andre

This is a fossilized aquatic bug from the Orbagnoux outcrop of the Rhone valey: Gallomesovelia grioti (scale bar 1 mm).
Credit: Nel Andre

The newly discovered insect was described today, in the open access journal PeerJ. The bug was 6 mm long and is the oldest record of the aquatic bug lineage of the Gerromorpha which comprises the water striders and the water measurers. This is the oldest known water treader (Mesoveliidae), the sister group of all other gerromorphan lineages. In a similar manner to some of its recent relatives, this aquatic bug could have lived in brackish environments.

In addition, traces of insect activity on plants were found, comprising surface feeding traces on Zamites leaves. Such traces are quite rare in the fossil record and in this situation they demonstrate the presence of strictly terrestrial insects on the emerged lands that were surrounded by these Jurassic lagoons.

The exquisite quality of preservation of the fossils suggests that these rocks are likely to provide new fossil insects of crucial importance for the knowledge of the Upper Jurassic insect fauna, an important transition period in the evolution of the terrestrial environments towards the Lower Cretaceous diversification of the flowering plants.

Ring Of Fire Tectonic Plate Is Cooling – And Shrinking

The tectonic plate that dominates the Pacific “Ring of Fire” is not as rigid as most assume, and it’s getting less fiery. according to researchers at Rice University and the University of Nevada.

Rice geophysicist Richard Gordon and Corné Kreemer, an associate professor at the University of Nevada, Reno, have determined that cooling of the lithosphere — the outermost layer of Earth — makes some sections of the Pacific plate contract horizontally at faster rates than others and cause the plate to deform. Gordon said the effect detailed is most pronounced in the youngest parts of the lithosphere — about 2 million years old or less — that make up some the Pacific Ocean’s floor. They predict the rate of contraction to be 10 times faster than older parts of the plate that were created about 20 million years ago and 80 times faster than very old parts of the plate that were created about 160 million years ago.

The tectonic plates that cover Earth’s surface, including both land and seafloor, are in constant motion; they imperceptibly surf the viscous mantle below. Over time, the plates scrape against and collide into each other, forming mountains, trenches and other geological features.


Red = volcanism; yellow = quake zones; black lines =plate boundaries. Link: Tamzin Kay

On the local scale, these movements cover only inches per year and are hard to see. The same goes for deformations of the type described in the new paper, but when summed over an area the size of the Pacific plate, they become statistically significant, Gordon said.

The new calculations showed the Pacific plate is pulling away from the North American plate a little more — approximately 2 millimeters a year — than the rigid-plate theory would account for, he said. Overall, the plate is moving northwest about 50 millimeters a year.

“The central assumption in plate tectonics is that the plates are rigid, but the studies that my colleagues and I have been doing for the past few decades show that this central assumption is merely an approximation — that is, the plates are not rigid,” Gordon said. “Our latest contribution is to specify or predict the nature and rate of deformation over the entire Pacific plate.”

The researchers already suspected cooling had a role from their observation that the 25 large and small plates that make up Earth’s shell do not fit together as well as the “rigid model” assumption would have it. They also knew that lithosphere as young as 2 million years was more malleable than hardened lithosphere as old as 170 million years.

“We first showed five years ago that the rate of horizontal contraction is inversely proportional to the age of the seafloor,” he said. “So it’s in the youngest lithosphere (toward the east side of the Pacific plate) where you get the biggest effects.”

A map produced by scientists at the University of Nevada, Reno, and Rice University shows predicted velocities for sectors of the Pacific tectonic plate relative to points near the Pacific-Antarctic ridge, which lies in the South Pacific ocean. The researchers show the Pacific plate is contracting as younger sections of the lithosphere cool. Credit: Corné Kreemer and Richard Gordon

The researchers saw hints of deformation in a metric called plate circuit closure, which describes the relative motions where at least three plates meet. If the plates were rigid, their angular velocities at the triple junction would have a sum of zero. But where the Pacific, Nazca and Cocos plates meet west of the Galápagos Islands, the nonclosure velocity is 14 millimeters a year, enough to suggest that all three plates are deforming.

“When we did our first global model in 1990, we said to ourselves that maybe when we get new data, this issue will go away,” Gordon said. “But when we updated our model a few years ago, all the places that didn’t have plate circuit closure 20 years ago still didn’t have it.”

There had to be a reason, and it began to become clear when Gordon and his colleagues looked beneath the seafloor. “It’s long been understood that the ocean floor increases in depth with age due to cooling and thermal contraction. But if something cools, it doesn’t just cool in one direction. It’s going to be at least approximately isotropic. It should shrink the same in all directions, not just vertically,” he said.

A previous study by Gordon and former Rice graduate student Ravi Kumar calculated the effect of thermal contraction on vertical columns of oceanic lithosphere and determined its impact on the horizontal plane, but viewing the plate as a whole demanded a different approach. “We thought about the vertically integrated properties of the lithosphere, but once we did that, we realized Earth’s surface is still a two-dimensional problem,” he said.

For the new study, Gordon and Kreemer started by determining how much the contractions would, on average, strain the horizontal surface. They divided the Pacific plate into a grid and calculated the strain on each of the nearly 198,000 squares based on their age, as determined by the seafloor age model published by the National Geophysical Data Center.

“That we could calculate on a laptop,” Gordon said. “If we tried to do it in three dimensions, it would take a high-powered computer cluster.”

The surface calculations were enough to show likely strain fields across the Pacific plate that, when summed, accounted for the deformation. As further proof, the distribution of recent earthquakes in the Pacific plate, which also relieve the strain, showed a greater number occurring in the plate’s younger lithosphere. “In the Earth, those strains are either accommodated by elastic deformation or by little earthquakes that adjust it,” he said.

“The central assumption of plate tectonics assumes the plates are rigid, and this is what we make predictions from,” said Gordon, who was recently honored by the American Geophysical Union for writing two papers about plate movements that are among the top 40 papers ever to appear in one of the organization’s top journals. “Up until now, it’s worked really well.”

“The big picture is that we now have, subject to experimental and observational tests, the first realistic, quantitative estimate of how the biggest oceanic plate departs from that rigid-plate assumption.”

Source:Articles on Science 2.0

Thylacares brandonesis : carnivorous crustacean 435 MYA

A new species of carnivorous crustacean has been identified, which roamed the seas 435 million years ago, grasping its prey with spiny limbs before devouring it. The fossil is described and details of its lifestyle are published in the open access journal BMC Evolutionary Biology.

The fossils were discovered near Waukesha, Wisconsin, with the new species, Thylacares brandonesis, named after the Brandon Bridge Formation where it was found. It is the oldest known example of the Thylacocephala group — shrimp-like creatures, mostly from the Jurassic period, known for their bulbous eyes and multiple limbs. The muscle structure and leg morphology of the new species suggests that it used its long, claw-like appendages to catch prey in a similar way to modern remipedes, blind crustaceans still found in salt water-filled caves.

Jurassic thylacocephalan Clausocaris lithographica. Credit: Haug et al. 2014

Jurassic thylacocephalan Clausocaris lithographica.
Credit: Haug et al. 2014

Derek Briggs, Yale University, says: “This new research extends the range of this enigmatic group of fossil arthropods back to the Silurian, some 435 million years ago, and provides evidence that they belong among the crustaceans, the modern group that includes lobsters, shrimps and crabs.”

Carolin Haug, LMU Munich, said: “T. brandonensis was probably an actively hunting predator, which caught the prey with its front claws and crushed it into smaller pieces with the protrusions nearer its mouthparts.”

“This early, Silurian, example of Thylacocephala is in many ways much less extreme than the more recent Jurassic species. It still has normal-sized eyes in contrast to the very enlarged ones that came later, and shorter front claws in T. brandonensis compared to the extremely elongated ones in more recent Jurassic representatives.”

The description of the new Silurian species was part of a wider investigation into this group of fossils, including several new Jurassic specimens. Modern imaging techniques allowed the scientists to visualise new features, such as the tiny details of the T. brandonensis muscle structure. Based on these images, they created 3D models of the new species, which help us to understand the creature’s life habits.

WFS Dinosaur Diary: QUETZALCOATLUS

Quetzalcoatlus was the largest pterosaur that ever lived; in fact, this airplane-sized reptile was the largest animal ever to take to the skies, period. Here are 10 facts you may (or may not) have known about Quetzalcoatlus.

QUETZALCOATLUS

QUETZALCOATLUS

1. Quetzalcoatlus was named after an Aztec god.

Flying, feathered, reptilian deities have figured in Central American mythology since at least 500 A.D. The Aztec god Quetzalcoatl literally translates as “feathered serpent;” even though Quetzalcoatlus didn’t have feathers, the reference seemed appropriate when this giant pterosaur was first described back in 1971. (And no, this doesn’t mean that pterosaurs flew the skies during Aztec times!)

2. The wingspan of Quetzalcoatlus exceeded 30 feet.

Although its exact proportions are still a matter of dispute, there’s no doubt that Quetzalcoatlus had an enormous wingspan, exceeding 30 feet from tip to tip and possibly attaining breadths of up to 40 feet–about the size of a small private jet. By way of comparison, the largest flying bird alive today, the Andean Condor, has a wingspan of only 10 feet and weighs an order of magnitude less.

Size

Size

3. Quetzalcoatlus probably had a cold-blooded metabolism.

As was the case with all pterosaurs, the wings of Quetzalcoatlus consisted of bare, extended flaps of leathery skin. The lack of accompanying feathers implies that Quetzalcoatlus possessed a reptilian, cold-blooded metabolism, in sharp contrast to the feathered theropod dinosaurs it coexisted with during the late Cretaceous period (which may well have possessed endothermic metabolisms).

4. Quetzalcoatlus took off using both its front and hind legs…

The enormous size of Quetzalcoatlus poses some serious issues, not least of which is how it launched itself into flight. One analysis suggests that this pterosaur vaulted itself into the air with its heavily muscled front legs, and only secondarily used its long, spindly hind limbs. There’s also a case to be made that Quetzalcoatlus preferred to launch itself over the edge of steep cliffs!

Fossil

Fossil

5. …and flew without flapping its wings.

Assuming that it had a cold-blooded metabolism, Quetzalcoatlus would have been unable to continuously flap its wings while in flight (a task that requires enormous amounts of energy). According to one analysis, this pterosaur preferred to glide through the air at elevations of 10,000 to 15,000 feet and speeds as fast as 80 miles per hour, only occasionally pivoting its gigantic wings.

6. …that is, if it even flew at all.

Just because Quetzalcoatlus was a pterosaur doesn’t necessarily mean that it was capable of (or interested in) flight. Some paleontologists insist that Quetzalcoatlus was actualy adapted for life on land, and hunted its prey on two feet like a big, gangly theropod. Still, it’s unclear, evolutionarily speaking, why Quetzalcoatlus would have retained such huge wings if it spent all its time on the ground.

7. Quetzalcoatlus was an “azhdarchid” pterosaur.

Although it was certainly one of the biggest, Quetzalcoatlus wasn’t the only plus-sized pterosaur of the late Cretaceous period. Other “azhdarchid” pterosaurs, as they’re called by paleontologists, include Alanqa, Hatzegopteryx, and the poorly understood Azhdarcho; these azhdarchids were also closely related to the South American Tupuxuara and Tapejara.

8. It’s uncertain how much Quetzalcoatlus weighed…

Perhaps because paleontologists can’t quite wrap their minds around a flying reptile the size of fighter jet, there has been considerable disagreement about how much Quetzalcoatlus weighed. Early estimates posited a relatively svelte (and aerodynamic) 200 to 300 pounds, but recent studies suggest that this pterosaur may have weighed as much as a quarter of a ton.

9. …or what it ate for lunch and dinner.

When Quetzalcoatlus was first discovered, its long, narrow beak suggested that this pterosaur skimmed over the shallow seas of late Cretaceous North America, spearing fish and marine reptiles; one paleontologist has even speculated that it scavenged the corpses of deceased titanosaurs. It now seems more likely that Quetzalcoatlus hunted terrestrial animals, including small dinosaurs.

10. Quetzalcoatlus went extinct 65 million years ago.

As any Triceratops or Tyrannosaurus Rex will tell you, sheer size is no insurance policy against oblivion. Along with its fellow pterosaurs, Quetzalcoatlus went extinct at the end of the Cretaceous period, succumbing to the same environmental pressures (including a severe disruption of the food chain) as its dinosaur and marine reptile cousins in the wake of the K/T meteor impact.

Jurassic mammals were picky eaters.

New analyses of tiny fossil mammals from Glamorgan, South Wales are shedding light on the function and diets of our earliest ancestors, a team including researchers from the University of Southampton report today in the journal Nature. Mammals and their immediate ancestors from the Jurassic period (201-145 million years ago) developed new characteristics — such as better hearing and teeth capable of precise chewing.

By analysing jaw mechanics and fossil teeth, the team were able to determine that two of the earliest shrew-sized mammals, Morganucodon and Kuehneotherium, were not generalised insectivores but had already evolved specialised diets, feeding on distinct types of insects.

Morganucodon and Kuehneotherium. Credit: Pamela Gill

Morganucodon and Kuehneotherium.
Credit: Pamela Gill

Lead author, Dr Pamela Gill of the University of Bristol, said: “None of the fossils of the earliest mammals have the sort of exceptional preservation that includes stomach contents to infer diet, so instead we used a range of new techniques which we applied to our fossil finds of broken jaws and isolated teeth. Our results confirm that the diversification of mammalian species at the time was linked with differences in diet and ecology.”

The team used synchrotron X-rays and CT scanning to reveal in unprecedented detail the internal anatomy of these tiny jaws, which are only 2cm in length. As the jaws are in many pieces, the scans were ‘stitched together’ to make a complete digital reconstruction. Finite element modelling, the same technique used to design hip joints and bridges, was used to perform a computational analysis of the strength of the jaws. This showed that Kuehneotherium and Morganucodon had very different abilities for catching and chewing prey.

Study co-author, Dr Neil Gostling from the University of Southampton, said: “The improvement in CT scanning, both in the instrumentation, at Light Source at the Paul Scherrer Institute in Switzerland where we scanned or even the µ-VIS Centre at Southampton, along with access for research of this kind, allows us to make inroads into understanding the biology and the ecology of animals long dead. The questions asked of the technology do not produce ‘speculation’, rather the results show a clearly defined answer based on direct comparison to living mammals. This would not be possible without the computational techniques we have used here.”

Using an analysis previously carried out on the teeth of present-day, insect-eating bats, the researchers found that the teeth of Morganucodon and Kuehneotherium had very different patterns of microscopic pits and scratches, known as ‘microwear’. This indicated they were eating different things with Morganucodon favouring harder, crunchier food items such as beetles while Kuehneotherium selected softer foods such as scorpion flies which were common at the time.

Team leader, Professor Emily Rayfield from the University of Bristol, added: “This study is important as it shows for the first time that the features that make us unique as mammals, such as having only one set of replacement teeth and a specialised jaw joint and hearing apparatus, were associated with the very earliest mammals beginning to specialise their teeth and jaws to eat different things.”

Courtesy: University of Southampton. “Jurassic mammals were picky eaters, new study finds.” ScienceDaily. ScienceDaily, 20 August 2014.