Moabosaurus discovered in Utah's 'gold mine'

Move over, honeybee and seagull: it's time to meet Moabosaurus utahensis, Utah's newly discovered dinosaur, whose past reveals even more about the state's long-term history.

BYU researcher Brooks Britt with the newly discovered Moabosaurus, on display 
at BYU's Museum of Paleontology [Credit: Jaren Wilkey, BYU]

The Moabosaurus discovery was published this week by the University of Michigan's Contributions from the Museum of Paleontology. The paper, authored by three Brigham Young University researchers and a BYU graduate at Auburn University, profiles Moabosaurus, a 125-million-year-old dinosaur whose skeleton was assembled using bones extracted from the Dalton Wells Quarry, near Arches National Park.

BYU geology professor and lead author Brooks Britt explained that in analyzing dinosaur bones, he and colleagues rely on constant comparisons with other related specimens. If there are enough distinguishing features to make it unique, it's new.

"It's like looking at a piece of a car," Britt said. "You can look at it and say it belongs to a Ford sedan, but it's not exactly a Focus or a Fusion or a Fiesta. We do the same with dinosaurs."

BYU researcher Brooks Britt with the newly discovered Moabosaurus, on display 
at BYU's Museum of Paleontology [Credit: Jaren Wilkey, BYU]

Moabosaurus belongs to a group of herbivorous dinosaurs known as sauropods, which includes giants such as Brontosaurus and Brachiosaurus, who had long necks and pillar-like legs. Moabosaurus is most closely related to species found in Spain and Tanzania, which tells researchers that during its time, there were still intermittent physical connections between Europe, Africa and North America.

Moabosaurus lived in Utah before it resembled the desert we know -- when it was filled with large trees, plentiful streams, lakes and dinosaurs. "We always think of Moab in terms of tourism and outdoor activities, but a paleontologist thinks of Moab as a gold mine for dinosaur bones," Britt said.

In naming the species, Britt and his team, which included BYU Museum of Paleontology curator Rod Scheetz and biology professor Michael Whiting, decided to pay tribute to that gold mine. "We're honoring the city of Moab and the State of Utah because they were so supportive of our excavation efforts over the decades it's taken us to pull the animal out of the ground," Britt said, referencing the digs that began when he was a BYU geology student in the late '70s.

A previous study indicates that a large number of Moabosaurus and other dinosaurs died in a severe drought. Survivors trampled their fallen companions' bodies, crushing their bones. After the drought ended, streams eroded the land, and transported the bones a short distance, where they were again trampled. Meanwhile, insects in the soils fed on the bones, leaving behind tell-tale burrow marks.

"We're lucky to get anything out of this site," Britt said. "Most bones we find are fragmentary, so only a small percentage of them are usable. And that's why it took so long to get this animal put together: we had to collect huge numbers of bones in order to get enough that were complete."

BYU has a legacy of collecting dinosaurs that started in the early 1960s, and Britt and colleagues are continuing their excavation efforts in eastern Utah. Moabosaurus now joins a range of other findings currently on display at BYU's Museum of Paleontology -- though, until its placard is updated, it's identified as "Not yet named".

"Sure, we could find bones at other places in the world, but we find so many right here in Utah," Britt said. "You don't have to travel the world to discover new animals."

Author: Brooke Adams | Source: Brigham Young University [April 13, 2017]

byUnknown

in Dinosaurs, Fossils, North America, Palaeontology, USA

April 13, 2017

Moabosaurus discovered in Utah's 'gold mine'

Move over, honeybee and seagull: it's time to meet Moabosaurus utahensis, Utah's newly discovered dinosaur, whose past reveals even ...

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Paleontologists reappraise description of duck billed hadrosaurs

The duck-billed dinosaurs (hadrosaurs) may not be as glamorous as tyrannosaurs (and most tyrannosaur researchers sure don't respect these "Cretaceous food items" anyhow), but in many ways they are a far more interesting and scientifically viable group to study.

Skull of Edmontosaurus regalis [Credit: Xing et al. 2017]

Hadrosaurs are known from literally tons of fossils from around the world, often with nearly complete skeletons and frequent soft-tissue preservation. As a result, you can answer a lot of research questions with hadrosaurs that are difficult to address with more rare groups.

But, surprisingly (or perhaps not surprisingly, given many people's inexplicable preference for the sharp-in-tooth-and-claw tyrannosaurs), lots of basic research on hadrosaurs remains. This is a golden opportunity for scientists!

In many ways, Edmontosaurus is the archetype of hadrosaurs. Their fossils, abundant in North American rocks from around 72 to 66 million years old, are on display in numerous museums and have consequently been featured in toys and on television alike.

Early researchers, beginning in the first half of the 20th century, lavishly described and illustrated many of these specimens in the scientific literature. Yet, that grand tradition of detailed description has fallen somewhat fallow. We as scientists are often happy to rest on the laurels of our predecessors. If Edmontosaurus was already well-described back in 1920, what's the point in doing it again?

As paleontologists learn more about the anatomy and evolution of hadrosaurs, it's readily apparent that earlier workers didn't even know to bother describing, comparing, and illustrating certain features.

This is not their fault, of course–different aspects of anatomy are considered more relevant at different times. As additional species are uncovered or as old species are invalidated, the importance of some anatomical details is elevated, and that of other details is decreased. So, it never hurts to revisit "old" and well-described fossils.

Skeletal reconstruction of Edmontosaurus regalis [Credit: Xing et al. 2017]

A new paper by Hai Xing and colleagues redescribes skulls of the original Edmontosaurus species, Edmontosaurus regalis. Uncovered in Upper Cretaceous rocks of Alberta, over a dozen pretty decent crania, partial skeletons, and many fragments are known.

Edmontosaurus as a genus was recently revised, showing that many things previously lumped into various species and genera (including the old classics Anatosaurus and Anatotitan) were likely just two species of Edmontosaurus: E. regalis (the earlier Canadian form) and E. annectens (the later form found in both Canada and the United States).

An Alaskan form, Ugrunaaluk, was considered to be closely related. So, with all of the family tree stuff sorted out, now is a good time to review the variation within Edmontosaurus regalis and describe some newly relevant (and previously unrecognized) anatomical details.

The paper, published last week in PLOS ONE, provides detailed illustrations and text descriptions for numerous details on the skull in Edmontosaurus regalis. Once the anatomical work was out of the way, the authors re-evaluated previously proposed differences with the sister species E. annectens, and were able to add several formerly unrecognized features that can help separate the two species.

Next, a comprehensive analysis produced a new family tree, which was broadly similar to previously published versions but also had a few interesting adjustments. For instance, an animal from Alabama called Eotrachodon was found to fall outside of the main group of "true" hadrosaurids (rather than within the group as previously proposed). A number of other slight readjustments also appeared in the analysis, all of which have relevance for how hadrosaurs spread across the surface of the globe during their evolution.

Finally, restudy of Edmontosaurus regalis indicates a potential shake-up for the Alaskan duck-bill Ugrunaaluk. Ugrunaaluk is known from numerous specimens, but they are all juveniles. Xing and colleagues note many similarities between Ugrunaaluk and Edmontosaurus regalis–enough that they may even be the same species.

Frustratingly, though, no juveniles of E. regalis are known at a size similar to those for Ugrunaaluk, meaning that equivalent life stages from the animals can't be compared directly. So, we're back to the classic refrain: we need more fossils to know for sure!

Author: Andrew Farke | Source: PLOS Blogs [April 12, 2017]

byUnknown

in Canada, Dinosaurs, Fossils, Palaeontology

April 12, 2017

Paleontologists reappraise description of duck billed hadrosaurs

The duck-billed dinosaurs (hadrosaurs) may not be as glamorous as tyrannosaurs (and most tyrannosaur researchers sure don't respect thes...

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Discovery of early, 'croc-like' reptile sheds new light on evolution of dinosaurs

A new species of ancient reptile has been described by scientists at the University of Birmingham, filling a critical gap in the fossil record of dinosaur cousins and suggesting that some features thought to characterise dinosaurs evolved much earlier than previously thought.

A life reconstruction of the new species Teleocrater rhadinus, a close relative of dinosaurs, feasting on an ancient mammal 
relative, Cynognathus, in the Triassic of Tanzania. The large dicynodont Dolichuranus is seen in the background 
[Credit: Natural History Museum, London, artwork by Mark Witton]

Described in a paper published in Nature, the carnivorous reptile, Teleocrater rhadinus, was approximately 7-10 feet in length, had a long neck and tail, and walked on four crocodile-like legs.

It roamed the Earth during the Triassic Period more than 245 million years ago – pre-dating the first true dinosaurs by around ten million years – and appears in the fossil record just after a large group of reptiles, known as archosaurs, split into a bird branch (leading to dinosaurs and eventually birds) and a crocodile branch (eventually leading to today’s alligators and crocodiles). Teleocrater and its kin are the earliest known members of the bird branch of the archosaurs.

Scientists excavate the remains of Teleocrater rhadinus and other animals in southern Tanzania in 2015. Christian 
Sidor (left), Sterling Nesbitt (middle left), Kenneth Angielczyk (upper right), Michelle Stocker (lower right)
[Credit: Roger Smith]

The discovery overturns widely-held preconceptions by palaeontologists about the morphology of early dinosaur relatives, with many scientists anticipating that such creatures would be smaller, bipedal and more ‘dinosaur-like’.

‘Teleocrater fundamentally challenges our models of what the close relatives of dinosaurs would have looked like,’ says Professor Richard Butler from the University of Birmingham.

A simplified depiction of phylogenetic relationships within Archosauria, including Teleocrater rhadinus 
[Credit: Credit: Dr Richard Butler, University of Birmingham]

‘Dinosaurs were amazingly successful animals. It’s natural to want to know where they came from, and how they became so dominant. Teleocrater is hugely exciting because it blows holes in many of our classic ideas of dinosaur origins.’

All the specimens used to describe Teleocrater were collected from a rock unit called the Manda Beds, in the Ruhuhu Basin of southern Tanzania, Africa. Teleocrater fossils were first discovered in the region in 1933 by palaeontologist F. Rex Parrington, and subsequently studied by Alan J. Charig, former Curator of Fossil Reptiles, Amphibians and Birds at the Natural History Museum, in the 1950s.

However, due to a lack of crucial bones, such as the ankle bones, Charig could not determine whether Teleocrater was more closely related to crocodylians or to dinosaurs. Unfortunately, he died before he was able to complete his studies.

Re-examination of Charig’s specimens by Butler and colleagues, combined with the discovery of additional fossils by a US-led team in Tanzania in 2015, has finally allowed the surprising relationship between Teleocrater and its dinosaur cousins to be revealed.

‘It’s astonishing to think that it’s taken more than 80 years for the true scientific importance of these fossils to be understood and published,’ says Professor Butler.

Life model of the new species Teleocrater rhadinus, a close relative of dinosaurs, preying upona juvenile cynodont, 
a distant relative of mammals [Credit: Museo Argentino de Ciencias Naturales]

Professor Paul Barrett from the Natural History Museum, one of the other main authors of the work on Teleocrater, said:

‘My colleague Alan Charig would have been thrilled to see one of ‘his’ animals finally being named and occupying such an interesting position in the Tree of Life.

‘Our discovery shows the value of maintaining and re-assessing historical collections: many new discoveries, like this one, can be made by looking through museum collections with fresh eyes.’

Source: University of Birmingham [April 12, 2017]

byUnknown

in Dinosaurs, Fossils, Palaeontology, Tanzania

April 12, 2017

Discovery of early, 'croc-like' reptile sheds new light on evolution of dinosaurs

A new species of ancient reptile has been described by scientists at the University of Birmingham, filling a critical gap in the fossil reco...

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Could a Colorado earthquake have been triggered by dinosaur extinction impact?

Researchers have found signs of fault displacement at well-known rock outcrops in Colorado that mark the end-Cretaceous asteroid impact that may have hurried the extinction of the dinosaurs. They will present their results in a poster at the 2017 Seismological Society of America's (SSA) Annual Meeting.

Longs Canyon area of Colorado's Trinidad Lakes State Park [Credit: WikiCommons]

Norm Sleep of Stanford University and colleagues suggest that the impact, which occurred near the Yucatán Peninsula of Mexico, could have generated massive seismic waves that triggered earthquakes as far away as Colorado, in the center of a tectonic plate where no previous fault had existed.

Sleep and his colleagues found evidence for the fault in two areas in Colorado's Trinidad Lakes State Park, where a layer of iridium generated by the asteroid impact clearly marks the boundary between Cretaceous and Tertiary-age rocks, at the time of the dinosaurs' extinction about 65 million years ago. At the Long's Canyon and Madrid Canyon roadcuts, "there is a fault that slipped about a meter at the time of the impact," Sleep said. "It offset the material below the impact layer but not above, but it's not something that would be obvious to the casual observer."

The researchers suggest that the Colorado earthquake may have been as large as magnitude 6. Very strong seismic waves from the impact -- much larger than would be generated by a regular earthquake, Sleep said -- would be necessary to trigger an earthquake in this location, in the middle of a tectonic plate with no previous faults.

The end-Cretaceous asteroid strike, however, could have generated ground velocities of a meter or two per second, Sleep said. "The ground would be moving up and down and sideways like a ship in a strong storm."

At the time of the earthquake, the area in Colorado was a swampy, delta-like environment, crossed by large braided streams that ran from the young Rocky Mountains. Sleep and his colleagues saw signs that the earthquake had diverted a small stream in the area.

This summer, the researchers will be checking in New Mexico near the Raton Basin for further signs of intraplate quakes that may have been triggered by the asteroid strike.

Source: Seismological Society of America [April 11, 2017]

byUnknown

in Dinosaurs, Earth Science, Geology, North America, Palaeontology, USA

April 11, 2017

Could a Colorado earthquake have been triggered by dinosaur extinction impact?

Researchers have found signs of fault displacement at well-known rock outcrops in Colorado that mark the end-Cretaceous asteroid impact that...

Read More

New indications of gradual decline of dinosaurs before the end of the Cretaceous period

According to the latest research results of a German-Mexican team of geoscientists, the gradual decline of the dinosaurs and pterosaurs presumably came before the impact of the Chicxulub asteroid and the global mass extinction at the end of the Cretaceous Period.

The gradual decline of the dinosaurs and pterosaurs presumably came before the impact of the Chicxulub asteroid and the 
global mass extinction at the end of the Cretaceous Period, new research suggests. Studies also indicate that bird species 
spread and diversified at the same time the dinosaurs disappeared [Credit: Kerem Beyit]

Studies under the direction of Prof. Dr Wolfgang Stinnesbeck of Heidelberg University and Prof. Dr Eberhard Frey of the State Museum of Natural History Karlsruhe also indicate that bird species spread and diversified at the same time the dinosaurs disappeared. Their results were published in the journal Geological Society of America Bulletin.

While conducting paleontological research in northeastern Mexico, the scientists came upon sedimentary rock deposited toward the end of the Cretaceous Period that evidenced an enormous diversity of fossils, including the tracks of birds, dinosaurs and pterosaurs.

"Most of the imprints come from at least five different species of birds; dinosaur tracks, however, are rare. Only a single footprint comes from a predatory dinosaur," explains Prof. Stinnesbeck. The finds therefore indicate a gradual decline of the dinosaurs with a simultaneous increase in the diversity of birds even before the end of the Cretaceous Period.

Landscape in the Paredon area: There the researchers encountered fossil imprints while conducting
 paleontological research [Credit: Wolfgang Stinnesbeck]

"Until now, it was generally assumed that the dinosaurs died out first and bird species diversified afterward," states the researcher. "Our data, however, substantiate the theory that birds ascended before dinosaurs became extinct."

Fossil analysis also showed that the decline of the dinosaurs occurred gradually, with probably only a few species surviving until the end of the Cretaceous Period. The extinction of the dinosaurs is therefore not -- as science frequently assumes -- due to the impact of the Chicxulub asteroid that struck Earth more than 65 million years ago.

"For most of the dinosaurs and pterosaurs, this strike no longer had any effect," explains Prof. Stinnesbeck. Even the group of cephalopods, the so-called ammonites, was not annihilated by the asteroid strike at the end of the Cretaceous Period. According to Prof. Stinnesbeck, fossil finds of the Sphenodiscus pleurisepta ammonite show their successive decline beyond the Cretaceous Period.

"The effects of the Chicxulub impact were therefore not the cause of a global mass extinction, which probably came about considerably less catastrophically than previously assumed," states the Heidelberg researcher.

Source: Heidelberg University [April 03, 2017]

byUnknown

in Dinosaurs, Early Birds, Fossils, Palaeontology, USA

April 03, 2017

New indications of gradual decline of dinosaurs before the end of the Cretaceous period

According to the latest research results of a German-Mexican team of geoscientists, the gradual decline of the dinosaurs and pterosaurs pres...

Read More