Dinosaur age crab named after amateur paleontologist


Distefania vanrijsselti

This is a picture of the fossil crab species Distefania vanrijsselti; discovered near Maastricht in the Netherlands; from the Cretaceous, when dinosaurs ruled the earth. It was not a big crab; the yardstick at the bottom of the picture is one centimeter.

Translated from Vroege Vogels radio in the Netherlands, 5 October 2014:

During many hundreds of Saturdays amateur paleontologist Willy Rijsselt, along with his son Erik could be found in the quarry ‘t Rooth, near Maastricht. He managed to secure an unprecedented amount of fossils for his own collection, but also for science. By way of tribute, there is now a 67 million year old crab named after him: the Distefania vanrijsselti.

Tyrannosaurs, what we don’t know


This video is called Tyrannosaur Rivalry – Planet Dinosaur – Episode 3 – BBC One.

From the Things We Don’t Know blog:

Tuesday, 23 September 2014

Ten Things We Don’t Know about Tyrannosaurs

Tyrannosaurus rex and its closest relatives, the tyrannosaurs, are among the best known and most popular dinosaurs – and yet there is still plenty we don’t know about these fascinating creatures…

1. What age could T. rex live to?
It’s possible to work out how old a tyrannosaur was when it died, by looking at growth rings inside its bones – just like counting the rings of a tree. The oldest T. rex yet examined in this way has been nicknamed Sue, and is on display at the Field Museum. It’s thought that Sue was 28 years old[1] when it died. Only about a dozen skeletons have been cut up to determine their age, and there are other T. rex’s that look like they might be older than Sue, but haven’t had their growth rings counted. This means that we really don’t exactly know the maximum age of T. rex; it’s possible that it will turn out to be much more than 28 years once the sample of adults has increased.

2. How were tyrannosaurs related?
Evolutionary trees are diagrams that can be drawn to show how animals are related to each other. Researchers gather data and use this to try to reconstruct the evolutionary history of a group of species – but it isn’t always simple. At the moment there are two versions of the evolutionary tree of tyrannosaurs[2][3] which differ in which species they include, and where they appear on the tree. As more data is collected, trees produced by different groups of researchers usually become more similar. It is likely that with more time and research we will, eventually, find a history that all of the available data supports. Until then though, how tyrannosaurs evolved remains something we don’t know.

3. What did their eggs, embryos, & hatchlings look like?
Despite the popularity of tyrannosaurs, we don’t know anything about the earliest growth stages of any tyrannosaur species. Currently, there are no skulls or skeletons of embryos or juveniles up to a year old. We don’t even know what a tyrannosaur eggshell looks like – very few embryos have been discovered inside fossilised eggs, which is the only way we could be certain of the species the egg belonged to, so the number of dinosaur species identified in this way is very low. It could be that tyrannosaur eggs have already been collected (among those that currently lack embryonic bones) but we just haven’t realised it yet! Hopefully this situation, at least for eggs and embryos, will change very soon as dinosaur eggs are being discovered all the time in places such as China.

4. Were there two groups of Tyrannosaurs in Laramidia?

It has been suggested that tyrannosaurs in the Late Cretaceous of western North America (Laramidia) can be divided into a northern group and a southern group[3]. However the fact that the fossil record from that period is incomplete throws doubt on this hypothesis. The far north and the far south of this region are virtually blank slates in terms of tyrannosaur fossils, and no fossils have yet been found from the 20 million years following the split of North America into the subcontinents of Laramidia and Appalachia. Once specimens have been found to fill the gaps, there is a chance that the proposed two groups will lose support and be replaced by something more complex.

5. What Tyrannosaurs lived in Appalachia?
It is extremely rare to find tyrannosaur fossils in the eastern region of North America, which existed as an island continent called Appalachia during the Late Cretaceous. In fact, only two species have been found, we only know of one skeleton for each of them, and neither is complete. We can tell from these that the eastern tyrannosaurs are more primitive than their western counterparts; they have shallow snouts and large arms, in contrast to the deep snouts and short arms seen in the Laramidian and Asian species. Finding out more about these animals would give clues as to what the ancestors of tyrannosaurs looked like in North America before it was split into two, but the rarity of these fossils means that Appalachia may remain the ‘dark continent’ of tyrannosaur history.

6. How long ago did the Nemegt species live?
The Nemegt Formation in the Mongolian People’s Republic is a rich source of fossils, and includes well-known tyrannosaurs such as Tyrannosaurus bataar (Tarbosaurus) and Alioramus. It is clear from looking at these fossils that they are closely related to those found in Laramidia, which suggests animals moved from one area to the other. Currently, however, we don’t know when, or in which direction, the exchange occurred. It is thought the Nemegt fauna occurred close to the end of the age of dinosaurs, but before the last slice of time that included T. rex. Often, the age of rocks can be determined by looking for the presence of certain radioactive materials, but unfortunately this hasn’t been possible in the Nemegt Formation as the materials aren’t present. This means we only have a rough idea of how long ago the rocks formed[4]. To narrow it down from the current estimate of 80-66 million years ago, we need to find a new area of rock that is possible to date but, unfortunately, this seems unlikely.

7. Did advanced tyrannosaurs have scales?
We have all seen pictures and models of T. rex looking like a giant lizard, but in reality we don’t know what covered the skin of advanced tyrannosaurs. More and more types of dinosaurs, and their relatives the flying pterosaurs (including Pterodactylus), are being found with feathers and hair-like structures on their skin, which would make them appear very different to the images in popular media. However, in some lineages such as sauropods, duckbilled dinosaurs and horned dinosaurs, feathers were lost, and scales reappeared. When it comes to tyrannosaurs, the picture is less clear. The most ancient tyrannosaurs were feathery in species big (Yutyrannus) and small (Dilong), but the presence of scales is known from patches in a handful of specimens of advanced tyrannosaurs, although these have only been reported in passing without detailed description[5]. Most specimens aren’t well enough preserved to get a full picture of their external appearance. If, however, tyrannosaur mummies are found one day, this would cast light on this aspect of their appearance.

8. What happened in the middle Jurassic period?
Unfortunately, we can only discover what the fossil record allows, and there are periods of time where there is little to work with. One of these is the Middle Jurassic, which was between 176 and 161 million years ago. This means there is a gap in our knowledge of tyrannosaur evolution, and it is difficult to determine how they developed from so called ‘basal’ forms to the more ‘advanced’ tyrannosaurs, or if these forms are even related. Hopefully, the discovery of more fossils from this interval will help fill in the gaps and give us a better picture of the history of tyrannosaurs.

9. Why did the alioramins have such long, low snouts?
Tyrannosaur workers have recently seen the addition of a new lineage, the alioramins[6]. The species in this group, Alioramus and Qianzhousaurus, have long and low snouts, in contrast to the short and deep snouts seen in, say, T. rex. T rex used its snout to deliver powerful bites to its prey, so while it is likely the longer snouts of the alioramins are an adaptation to a different kind of prey, its exact function is presently unknown.

10. Were there any tyrannosaurs in Siberia?
So far, fossils of several types of Late Cretaceous dinosaurs have been found in the far northeast of Russia, but no tyrannosaurs[7]. It is thought that dinosaurs dispersed across Northeastern Siberia and the north slope of Alaska, when moving between between Asia and Laramidia during the Late Cretaceous, so it is likely there are specimens here waiting to be found. Whatever tyrannosaur species are found in Siberia, they will be entirely new to science and they will certainly jostle the family tree.

This article was written by Dr Thomas Carr PhD, a vertebrate paleontologist who specializes in the growth and evolution of tyrannosaurs. He has named three new genera of tyrannosaurs, namely Appalachiosaurus (Alabama), Bistahieversor (New Mexico), and Teratophoneus (Utah), and he was part of the team who named Alioramus altai (Mongolia). Dr. Carr was the first to publish growth series of dinosaurs using cladistic analysis, a method usually used for recovering evolutionary relationships, for Tyrannosaurus rex and Albertosaurus sarcophagus. He collects dinosaur fossils with his students and volunteers each summer on federally regulated lands in southeastern Montana. Dr. Carr is an Associate Professor of Biology at Carthage College (Kenosha, WI), the Director of the Carthage Institute of Paleontology, and the Senior Scientific Adviser to the Dinosaur Discovery Museum (Kenosha, WI). You can visit Dr. Carr’s blog, Tyrannosauroidea Central, and follow his tweets at @Tyrannosaurcarr.

References
why don’t all references have links?

[1] Erickson, Gregory M et al. “Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs.” Nature 430.7001 (2004): 772-775. doi:10.1038/nature02699
[2] Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., and Xu, X. 2010. “Tyrannosaur paleobiology: New research on ancient exemplar organisms.” Science 329: 1481-1485.
[3] Loewen MA, Irmis RB, Sertich JJW, Currie PJ, Sampson SD (2013) “Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans.” PLoS ONE 8(11): e79420. doi:10.1371/journal.pone.0079420
[4] Shuvalov, V. F. 2000. “The Cretaceous stratigraphy and paleobiogeography of Mongolia.” In Benton, M. J., Shichkin, M. A., Unwin, D. M., and Kurochkin, E. N. (eds.) The Age of Dinosaurs in Russia and Mongolia, pp. 256-278. Cambridge University Press, Cambridge.
[5] Currie, P. J. 2004. “Theropods, Including Birds.” In Currie, P. J. and Koppelhus, E. B. (eds.) Dinosaur Provincial Park: A spectacular ancient ecosystem revealed; pp. 367-397. Indiana University Press, Bloomington and Indianapolis.
[6] Lu, J., Yi, L., Brusatte, S. L., Yang, L., Li, H., and Chen, L. 2014. “A new clade of Asian Late Cretaceous long-snouted tyrannosaurids.” Nature Communications 5, article number: 3788. doi:10.1038/ncomms4788
[7] Weishampel, D. B., Barrett, P. M., Coria, R. A., Le Loeuff, J., Xing, X., Xijin, Z., Sahni, A., Gomani, E. M. P., and Noto, C. “Dinosaur Distribution.” In Weishampel, D. B., Dodon, P., and Osmolska, H. (eds.) The Dinosauria Second Edition, pp. 517-606. University of California Press, Berkeley.
[8] Horner, John R.; Weishampel, David B.; Forster, Catherine A (2004). “Hadrosauridae”. In Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 438–463. ISBN 0-520-24209-2.

Dinosaur with big nose discovery


This video is about hadrosaurs.

From North Carolina State University in the USA:

Hadrosaur with huge nose discovered: Function of dinosaur’s unusual trait a mystery

September 19, 2014

Call it the Jimmy Durante of dinosaurs — a newly discovered hadrosaur with a truly distinctive nasal profile. The new dinosaur, named Rhinorex condrupus by paleontologists from North Carolina State University and Brigham Young University, lived in what is now Utah approximately 75 million years ago during the Late Cretaceous period.

Rhinorex, which translates roughly into “King Nose,” was a plant-eater and a close relative of other Cretaceous hadrosaurs like Parasaurolophus and Edmontosaurus. Hadrosaurs are usually identified by bony crests that extended from the skull, although Edmontosaurus doesn’t have such a hard crest (paleontologists have discovered that it had a fleshy crest). Rhinorex also lacks a crest on the top of its head; instead, this new dinosaur has a huge nose.

Terry Gates, a joint postdoctoral researcher with NC State and the North Carolina Museum of Natural Sciences, and colleague Rodney Sheetz from the Brigham Young Museum of Paleontology, came across the fossil in storage at BYU. First excavated in the 1990s from Utah’s Neslen formation, Rhinorex had been studied primarily for its well-preserved skin impressions. When Gates and Sheetz reconstructed the skull, they realized that they had a new species.

“We had almost the entire skull, which was wonderful,” Gates says, “but the preparation was very difficult. It took two years to dig the fossil out of the sandstone it was embedded in — it was like digging a dinosaur skull out of a concrete driveway.”

Based on the recovered bones, Gates estimates that Rhinorex was about 30 feet long and weighed over 8,500 lbs. It lived in a swampy estuarial environment, about 50 miles from the coast. Rhinorex is the only complete hadrosaur fossil from the Neslen site, and it helps fill in some gaps about habitat segregation during the Late Cretaceous.

“We’ve found other hadrosaurs from the same time period but located about 200 miles farther south that are adapted to a different environment,” Gates says. “This discovery gives us a geographic snapshot of the Cretaceous, and helps us place contemporary species in their correct time and place. Rhinorex also helps us further fill in the hadrosaur family tree.”

When asked how Rhinorex may have benefitted from a large nose Gates said, “The purpose of such a big nose is still a mystery. If this dinosaur is anything like its relatives then it likely did not have a super sense of smell; but maybe the nose was used as a means of attracting mates, recognizing members of its species, or even as a large attachment for a plant-smashing beak. We are already sniffing out answers to these questions.”

The scientific dewscription of this new species is here.

See also here.

Spinosaurus bigger than Tyrannosaurus, new research


This video is called Bigger Than T. rex: Spinosaurus.

From the University of Chicago in the USA:

Massive hunter prowled water’s edge

UChicago collaboration rediscovers African dinosaur Spinosaurus, 9 feet longer than T. rex

By Claire Gwatkin Jones

Scientists have unveiled 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 the Earth, measuring more than 9 feet longer than the world’s largest Tyrannosaurus rex specimen. These findings, published online Sept. 11 on the Science Express website, also are featured in the October National Geographic magazine cover story.

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. They also used 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.”

Aquatic adaptations of Spinosaurus

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.

Discovery more than century in making

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.”

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.

Originally published on September 11, 2014.

Utah dinosaur tracks site open to the public


This video from the USA is called Dinosaur Footprints Set For Public Display In Utah.

From Associated Press:

Site of dinosaur tracks to be unveiled

by Brady Mccombs

SALT LAKE CITY, UTAH – A dry wash full of 112-million-year-old dinosaur tracks that include an ankylosaurus, dromaeosaurus and a menacing ancestor of the Tyrannosaurus rex, is set to open to the public this fall in Utah.

There are more than 200 tracks near the city of Moab from 10 different ancient animals that lived during the early Cretaceous period, said Utah Bureau of Land Management paleontologist ReBecca Hunt-Foster.

They were first discovered in 2009 by a resident. Since then, paleontologists led by a team at the University of Colorado at Denver have studied them and prepared them to go on display for the general public.

The tracks include a set of 17 consecutive footprints left by [a] Tyrannosaurus rex ancestor and the imprint of an ancient crocodile pushing off into the water.

The site is one of the largest areas of dinosaur tracks from the early Cretaceous period known to exist in North America, she said.

“We don’t usually get this,” said Hunt-Foster, a paleontologist for 16 years. “It is a beautiful track site, one of the best ones I’ve ever seen.”

There are footprints from duckbilled dinosaurs, prehistoric birds, long-necked plant eaters and a dromaeosaur similar to a velociraptor or Utahraptor that had long, sharp claws.

In one rock formation, a footprint left behind by a large plant eater is right in the middle of prints from a meat-eating theropod, Hunt-Foster said.

The imprint of an ancient crocodile shows the chest, body, tail and one foot. Paleontologists believe it was made while the crocodile was pushing off a muddy bank into water.

Paleontologists believe the tracks were made over several days in what was a shallow lake. They likely became covered by sediment that filled them up quickly enough to preserve them but gently enough not to scour them out, Hunt-Foster said. Over time, as more sediment built up, they became rock. They’re near a fault line, where the land has moved up and down over the years, she said. Rain slowly eroded away layers of the rock, exposing the footprints.

Welsh Jurassic mammals feeding, new study


This video says about itself:

There Are No Transitional Fossils?

19 April 2011

Long-sought fossil mammal with transitional middle ear found in China.

Palaeontologists have announced the discovery of Liaoconodon hui, a complete fossil mammal from the Mesozoic found in China that includes the long-sought transitional middle ear.

The specimen was found by palaeontologists from the American Museum of Natural History and the Chinese Academy of Sciences.

It shows the bones associated with hearing in mammals, the malleus, incus, and ectotympanic, decoupled from the lower jaw, as had been predicted, but were held in place by an ossified cartilage that rested in a groove on the lower jaw.

People have been looking for this specimen for over 150 years since noticing a puzzling groove on the lower jaw of some early mammals,” Jin Meng, curator in the Division of Palaeontology at the Museum and first author of the paper, said.

“Now we have cartilage with ear bones attached, the first clear paleontological evidence showing relationships between the lower jaw and middle ear,” Meng revealed

The transition from reptiles to mammals has long been an open question, although studies of developing embryos have linked reptilian bones of the lower jaw joint to mammalian middle ear bones.

The new fossil, Liaoconodon hui, fills the gap in knowledge between the basal, early mammaliaforms like Morganucodon, where the middle ear bones are part of the mandible and the definitive middle ear of living and fossil mammals.

Liaoconodon hui is a medium-sized mammal for the Mesozioc (35.7 cm long from nose to tip of tail, or about 14 inches) and dates from 125 to 122 million years.

It is named in part for the bountiful fossil beds in Liaoning, China, where it was found.

The species name, hui, honours palaeontologist Yaoming Hu who graduated from the American Museum of Natural History-supported doctoral program and recently passed away.

The fossil is particularly complete, and its skull was prepared from both dorsal and ventral sides, allowing Meng and colleagues to see that the incus and malleus have detached from the lower jaw to form part of the middle ear.

These bones remain linked to the jaw by the ossified Meckels cartilage that rests in the groove on the lower jaw. The team hypothesizes that in this early mammal, the eardrum was stabilized with the ossified cartilage as a supporting structure.

“Before we did not know the detailed morphology of how the bones of the middle ear detached, or the purpose of the ossified cartilage,” Meng said.

“Liaoconodon hui changes previous interpretations because we now know the detailed morphology of the transitional mammal and can propose that the ossified cartilage is a stabilizer.

“I”ve always dreamed of a fossil with a good ear ossicle. Now, we have had this once in a lifetime discovery,” Meng added.

From the University of Southampton in England:

Jurassic mammals were picky eaters, new study finds

August 20, 2014

Summary:

New analyses of tiny fossil mammals from Glamorgan, South Wales are shedding light on the function and diets of our earliest ancestors, a team reports. 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.

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.

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.”

‘Butterfly-headed’ pterosaurs discovery in Brazil


A new species of flying reptile from the Cretaceous Era, Caiuajara dobruskiii, has been unearthed in southern Brazil. The creature, described in a 2014 PLOS ONE paper, sported a bony crest on its head. Credit: Maurilio Oliveira/Museu Nacional-UFRJ

From Live Science:

Flock of Ancient ‘Butterfly-Headed’ Flying Reptiles Discovered

By Tia Ghose, Staff Writer

August 13, 2014 02:00pm ET

An ancient flying reptile with a bizarre, butterflylike head has been unearthed in Brazil.

The newfound reptile species, Caiuajara dobruskii, lived about 80 million years ago in an ancient desert oasis. The beast sported a strange bony crest on its head that looked like the wings of a butterfly, and had the wingspan needed to take flight at a very young age.

Hundreds of fossils from the reptile were unearthed in a single bone bed, providing the strongest evidence yet that the flying reptiles were social animals, said study co-author Alexander Kellner, a paleontologist at the Museu Nacional/Universidade Federal do Rio de Janeiro in Brazil. [See Images of the Bizarre 'Butterfly Head' Reptile]

Rare find

Though pterosaur fossils have been unearthed in northern Brazil, no one knew of pterosaurs fossils in the southern part of the country. In the 1970s, a farmer named Dobruski and his son discovered a massive Cretaceous Period bone bed in Cruzeiro do Oeste in southern Brazil, a region not known for any fossils, Kellner said. The find was forgotten for decades, and then rediscovered just two years ago. The team dubbed the reptile Caiuajara dobruskii, after the geologic formation, called the Caiuá Group, where it was found, as well as the farmer who discovered the species, Kellner said.

C. dobruskii belonged to a group of winged reptiles known as pterosaurs, which are more commonly known as pterodactyls.

Hundreds of bone fragments from the species were crammed in an area of just 215 square feet (20 square meters). At least 47 individuals — and possibly hundreds more — were buried at the site. All but a few were juveniles, though the researchers found everything from youngsters with wingspans of just 2.1 feet (0.65 m) long to adults with wingspans reaching 7.71 feet (2.35 m). The fossils weren’t crushed, so the 3D structure of the animals was preserved, the authors wrote in a research article published today (Aug. 13) in the journal PLOS ONE.

The ancient reptiles’ bony crests changed in size and orientation as the pterosaurs grew.

Because the adult skeletal size (other than the head) wasn’t much different from the juveniles’, the researchers hypothesized that C. dobruskii was fairly precocious and could fly at a young age, Kellner said.

Water congregation

Based on the sediments in which the bones were found, the area was once a vast desert with a central oasis nestled between the sand dunes, the authors wrote in the paper.

Ancient C. dobruskii colonies may have lived around the lake for long periods of time and died during periods of drought or during storms. As the creatures died, the occasional desert storm would wash their remains into the lake, where the watery burial preserved them indefinitely, the researchers said. Another possibility is that the pterosaurs stopped at this spot during ancient migrations, though the authors suspect that is less likely.

The bone bed, with its hundreds of individuals in well-dated geological layers, is some of the strongest evidence yet that the fruit-eating animals were social, Kellner said.

“This was a flock of pterosaurs,” Kellner told Live Science.

This finding, in turn, strengthens evidence that other pterosaur species may have been social as well, the authors wrote in the paper.