Tyrannosaur evolution, new research


This video from the American Museum of Natural History in the USA says about itself:

2 July 2012

Fossils of two never-before-seen species of tyrannosaur are overturning long-held ideas about the diversity and evolution of this family of dinosaurs. One is an unusually slender, eight-horned tyrannosaur named Alioramus altai, unveiled by AMNH Chair of Paleontology Mark Norell and AMNH/Columbia University PhD student Stephen Brusatte. The other is an ancient, tiny version of Tyrannosaurus rex called Raptorex kriegsteini, recently described by University of Chicago paleontologist Paul Sereno.

From PLOS Paleo blog:

The evolution of tyrannosaurs

Posted February 17, 2016 by Jon Tennant

T. rex is probably the most notorious and infamous dinosaur of all time, and somewhat of an icon in both the scientific and public spheres. After all, it was a pretty fearsome and impressive carnivore, and arguably worthy of such admiration. But there were actually a lot of other dinosaurs similar to T. rex, together forming a group known as tyrannosauroids.

Recently, a whole series of new findings is helping us to unlock the secrets of these fascinating beasts, and we can now begin to answer questions about their evolutionary relationships, biogeography, and how decent their fossil record is. In fact, half of all known tyrannosauroid species have been discovered in the last decade alone!

Tyrannosauroid species were actually around way before T. rex, which only occupied the top of the food chain right at the end of the Cretaceous reign of the non-avian dinosaurs. Actually, the largest tyrannosauroids only seemed to appear around 20 million years before this. Before they achieved such terrifyingly gigantic sizes, most were actually quite small-bodied (for a dinosaur), and quite ecologically diverse.

Steve Brusatte, Thomas Carr and their colleagues visited the question of the inter-relationships of tyrannosauroids back in 2010. Forming hypotheses of relationships like this forms the basis for assessing important evolutionary factors, such as the origins and evolution of particular anatomical features, rates of evolution, diversity, anatomical disparity, and biogeography. So when another study produced alternative results to their earlier study, Brusatte and Carr decided to go back to the Mesozoic and reanalyse tyrannosauroids, but incorporating all of the recent bits of knowledge we have gained about them over the last few years.

In addition to this, Brusatte and Carr decided to approach this with a dual method. Typically, when palaeontologists create trees that form the basis of assessing evolutionary relationships, we use a method called parsimony. This looks at how many different anatomical changes have occurred between different species, and tries to provide the minimum number of changes in order to build a tree. They also decided to go Bayesian on their dataset though, something which hasn’t really taken off in palaeontology yet, and has been more widely applied to molecular analyses. This works slightly differently by analysing anatomical data (in the form of a character matrix) in a probabilistic framework, and by using more complicated models that treat characters in different ways. By using this combination of techniques, it is possible to see which results are congruent, and therefore which conclusions can be best supported.

Fortunately for Brusatte and Carr, the results of both analyses were quite similar overall, lending support to their conclusions. There are slight differences, which you can see by comparing the two trees figured here. The overall structure reveals that tyrannosauroids can be sub-divided into a basal clade of proceratosauroids, which includes taxa such as the feathered Yutyrannus and Guanlong; an intermediate grouping or grade of small- to medium-sized beasties; and the gigantic apex predators such as T. rex and Tarbosaurus that we all know thanks to the best scientific minds in Hollywood.

The authors do a great job of trying to work out why their results differ slightly, but as always, the devil is in the details and it can be quite difficult to figure out. Part of the reason for some of the discrepancies might be to do with missing data – we can never fully sample every organism that has lived, and palaeontologists accept that limit of the fossil record. In the case of tyrannosauroids, there is a 20 million year gap in their fossil record from just before the time when the Western Interior Seaway covered much of North America. What this means is that animals simply weren’t preserved in the right time in the right place to be preserved as fossils. Yet, at least. Discovering new tyrannosauroids from this gap might be critical in working out how more derived tyrannosauroids evolved during a clearly important time in their history.

But what does all of this mean then for the evolution of tyrannosauroids? Well, for starters, it shows that the evolution of their large body size appeared to happen more gradually, rather than a rapid burst. Accompanying this, it shows that bite forces increased incrementally too, and that their elaborate facial ornamentations gradually became more complicated along with increasing body size. The first truly gigantic tyrannosauroids, coming in at more than 1.5 tonnes in mass and 10 metres in body length, didn’t appear in the fossil record until around 80 million years ago.

In terms of their biogeography, some interesting patterns emerge. It seems like there was episodic interchange between Asia and North America during the Late Cretaceous. What this means, and I’m sure Donald Trump will love this, is that T. rex actually appears to have been an Asian immigrant that colonised North America. However, this understanding might change as we recover ever more tyrannosauroid fossils from the latest Cretaceous of Asia and North America.

So, that’s a quick update on what we know about tyrannosauroids. Despite them clearly winning a cross-dinosaur popularity contest, there is still much we can learn about these creatures, and only time and future exploration can tell what we’ll discover!

Fossil dinosaur and fossil wildebeest, discoveries and simillarities


This video says about itself:

Shared noses: Extinct wildebeest relative was remarkably dinosaur-like

5 February 2016

An artist’s interpretation of Rusingoryx atopocranion on the Late Pleistocene plains of what is now Rusinga Island, Lake Victoria.

From the Christian Science Monitor in the USA:

Weird convergence: Extinct wildebeest cousin and dinosaur shared noses

Scientists discover two unrelated, extinct animals had the same strange nose.

By Eva Botkin-Kowacki, Staff writer February 5, 2016

You might not expect to find many similarities between a mammal and a reptile, particularly if they lived millions of years apart. But scientists have found that two such extinct beasts share a rare, distinctive facial feature.

An extinct relative of the wildebeest and a duck-billed dinosaur both had bizarre crests on their heads. But it wasn’t the protruding bump that has most intrigued scientists, it’s what they found beneath.

The bony crest is hollow, forming a trumpet-shaped nasal passage unlike any seen outside these two species. No other animal, living or dead, has been found with such a feature.

So how did two beasts from two very different taxa come to have such a mysterious commonality? Convergent evolution, scientists say in a paper published Thursday in the journal Current Biology.

“We have an animal that its skeleton looks a lot like a wildebeest – it’s actually very closely related to modern wildebeests – but its face looks a lot more like something you would see if you went way back in time to the Cretaceous and looked at hadrosaur dinosaurs,” study lead author Haley O’Brien tells The Christian Science Monitor in an interview.

Rusingoryx atopocranion, the mammal, lived about 65 thousand years ago, during the late Pleistocene, while Lambeosaurine hadrosaurs, the dinosaur, lived closer to 65 million years ago, during the late Cretaceous – and yet both animals evolved the same strange nose.

And not only do their nasal passages look alike, she said, the feature also appears to develop the same way as the animals grow up from juveniles to adults, as a variety of fossils display.

“When I first saw the complete skulls, I was blown away,” vertebrate paleontologist David C. Evans, who was not part of the study, writes in an email to the Monitor. “The resemblance between Rusingoryx and some hollow-crested dinosaurs in the form of their nasal structures is truly striking, and there are clear parallels in how they evolved and grew. Both groups elongated their noses to such a degree that they evolved highly domed skulls to house their nasal passages on top of their heads, above their eyes.”

Different origins, same result

“It’s probably one of the best examples of convergence in large animals that I’ve seen in a long time,” Ali Nabavizadeh, a researcher in evolutionary biology and anatomy at the University of Chicago, who was not involved in the study, tells the Monitor.

One was a mammal and the other a reptile, and millions of years elapsed between their tenure on Earth, but still, these animals developed the same adaptation.

Convergent evolution occurs when two species along different lineages independently evolve the same, or similar, features for the same function. One example is how insects, birds, and bats can all fly.

Convergence typically occurs when different species face the same ecological pressures. So what did Rusingoryx and the hadrosaurs have in common?

Both animals were herbivores and lived in herds. Rusingoryx was a ruminant and hadrosaurs have been called the cows of the Cretaceous, but the similarities, besides the shared nose, stop there.

Rusingoryx lived on the savanna, a dry wide open plain, while Lambeosaurine hadrosaurs were thought to have lived in a tropical rainforest.

Understanding this mysterious convergence might hinge on the purpose that these strange nasal passages served.

Inner trumpets

Without looking inside the animals’ skulls, the crest might appear to be simply for visual display or some other external use.

“We have known for decades that visual display and physical combat have strongly shaped skull evolution in many groups of animals with elaborate horns and crests,” Dr. Evans says. But the long, trumpet-shaped interior suggests a more complex purpose.

The hollow cavity, part of the respiratory tract, loops up over the animal’s head and seems to connect to the vocal tract.

To determine the purpose behind this strange nose, scientists focused on the mammal’s living cousins, wildebeests and antelopes. While researchers can look at their soft tissue for clues, all that’s left of the dinosaurs is bone.

The unusual nose could have helped the animals smell, bugle, or even regulate their temperature, Evans says. “The case for vocalization as the primary function of the nasal dome in Rusingoryx is by far the most convincing, as the authors advocate.”

The Rusingoryx are very social, says Ms. O’Brien. “They live in herds and they use a lot of vocal signals to communicate. When we looked into the function of what this skull type might be doing in Rusingoryx, we really couldn’t prescribe a function outside of that social vocalization.”

“There are obviously a lot of things that animals do with their faces,” she says. “But we don’t think that this crazy nasal dome would have really changed those more normal functions for this animal. We think that it was using the nasal crest to modify the way that it’s producing these vocalizations and communicating.”

That makes sense, says Thomas E. Williamson, curator of paleontology at the New Mexico Museum of Natural History and Science, who was not part of the study.

“When you have any kind of a tubing, it becomes naturally resonant,” he explains. “So the idea that it’s being used somehow to amplify certain frequencies of sound, it will do that,”

Not your average moo

O’Brien and her colleagues suggest that Rusingoryx, and perhaps the dinosaurs by extension, used this bizarre nasal dome to communicate at frequencies other animals cannot hear. This is called infrasound, and animals like elephants and cassowaries use it to communicate under the radar.

That’s possible, says Dr. Nabavizadeh. “If you have a very gregarious group of animals and they’re in a big arid, open environment, as these bovids are, then you are under the selective pressure to start to create more lower bellowing sounds that are possibly outside of the hearing range of carnivores, so they can communicate without being found in big open environments.”

But the environment doesn’t preclude the dinosaurs from needing this ability too, says Dr. Williamson. “Infrasound … is able to travel over great distances and open areas and in closed environments. It pretty much goes everywhere,” he says. And cassowaries, the living birds thought to communicate in infrasound, live in dense tropical rainforests.

Extremely big dinosaur discovery in Argentina


This 22 January 2016 Argentine TV video, in Spanish, is about the recent discovery of the Notocolossus gonzalezparejasi dinosaur.

From Nature:

A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot

18 January 2016

Abstract

Titanosauria is an exceptionally diverse, globally-distributed clade of sauropod dinosaurs that includes the largest known land animals. Knowledge of titanosaurian pedal structure is critical to understanding the stance and locomotion of these enormous herbivores and, by extension, gigantic terrestrial vertebrates as a whole. However, completely preserved pedes are extremely rare among Titanosauria, especially as regards the truly giant members of the group.

Here we describe Notocolossus gonzalezparejasi gen. et sp. nov. from the Upper Cretaceous of Mendoza Province, Argentina. With a powerfully-constructed humerus 1.76 m in length, Notocolossus is one of the largest known dinosaurs. Furthermore, the complete pes of the new taxon exhibits a strikingly compact, homogeneous metatarsus—seemingly adapted for bearing extraordinary weight—and truncated unguals, morphologies that are otherwise unknown in Sauropoda. The pes underwent a near-progressive reduction in the number of phalanges along the line to derived titanosaurs, eventually resulting in the reduced hind foot of these sauropods.

A Culture24 top ten of the best dinosaur museums and collections in the UK: here.

Jurassic dinosaur discovery in Wales


This video about Wales says about itself:

New dinosaur: Welsh dragon Dracoraptor hanigani discovered

20 January 2016

Scientists have discovered the fossilised skull and bones of a dinosaur on a Severn Estuary beach near the town of Penarth. Report by Sarah Duffy.

From daily The Independent in Britain today:

Ancient ‘dragon’ found in Wales, named Dracoraptor hanigani

The apparently youthful dinosaur was running around Wales about 200 million years ago

Andrew Griffin

Dragons really did roam around Wales. But about 200 million years ago.

Scientists have found the skull and bones of a huge beast near Penarth. The creature has been named Dracoraptor hanigani and is one of the world’s oldest Jurassic dinosaurs.

Dracoraptor is Latin for “dragon robber”, an apparent reference to the dragon on Wales’ flag.

Flag of Wales

The rest of the name comes from Nick and Rob Hanigan, the amateur fossil-hunters who found the bones while they were looking for ichthyosaur remains.

The dragon was related to the Tyrannosaurus rex. But it was a lot less terrifying, scientists say.

The bones aren’t yet fully formed, and so the specimen probably belongs to a youngster.

The dragon would have roamed before dinosaurs took over the world, when it was instead dominated by crocodiles and mammals.

Mammals just started their evolution during the early Jurassic, and were not dominant yet.

The climate of Wales would also have been very different and much warmer.

Dinosaur scientist Steven Vidovic, from the University of Portsmouth, one of the experts whose description of D. hanigani appears in the online journal Public Library of Science ONE, said: “The Triassic-Jurassic extinction event is often credited for the later success of dinosaurs through the Jurassic and Cretaceous, but previously we knew very little about dinosaurs at the start of this diversification and rise to dominance.

“Now we have Dracoraptor, a relatively complete two metre-long juvenile theropod from the very earliest days of the Jurassic in Wales.”

Tyrannosaurus rex in Leiden museum ‘an old lady’


This is a February 2015 Dutch TV video about a Tyrannosaurus rex going from Montana in the USA to the Netherlands.

In 2016, for the first time ever, people will be able to see a Tyrannosaurus rex skeleton in a museum outside North America: in Naturalis museum in Leiden, the Netherlands. The fossil skeleton will arrive there in mid-2016.

This dinosaur was found in Montana in 2013.

This morning, Naturalis paleontologist Anne Schulp, involved in the excavation, was interviewed by Dutch radio on this.

He said this Tyrannosaur is probably a female of over 30 years old. That would make her the Tyrannosaur with the longest life found so far.

Dinosaur love life discovery in Colorado, USA


This video from the USA says about itself:

5 August 2011

Dr. Martin Lockley answers the question “Why do dinosaur tracks contribute to our extinction theories?”

Dr. Martin Lockley is a renowned world expert in the fields of paleontology, geology and evolution. A native of England, he created the Dinosaur Tracks Museum at the University of Colorado at Denver, and is currently its director.

A fountain of knowledge on dinosaurs, fossil footprints and prehistoric creatures, renowned paleontologist Martin Lockley leads an expedition to find and identify dinosaur foot prints within the Gateway confines as well as an excursion just outside Gateway to search for more tracks.

This time, better news from Colorado, USA than last time.

From the Denver Post:

Dinosaur love nests unearthed on local land by Colorado researcher

Rubber molds and fiberglass copies of the scrapes are being stored at the Denver Museum of Nature and Science

By Elizabeth Hernandez

01/07/2016 07:00:00 AM MST

A skilled Colorado dinosaur tracker has unearthed 100 million-year-old dino love nests in Denver’s backyard.

The first evidence of dinosaur dating was discovered by Martin Lockley, a University of Colorado Denver geology professor who stumbled across large scratch marks in Colorado rocks. Initially, the marks had Lockley and his international team stumped.

Taking a cue from birds — relatives to the carnivorous dinos that lived in the area — Lockley said he and his crew started to think the scratches could be a ritual activity many male birds partake in: pseudo-nest-building.

“It’s like they’re showing off to a prospective mate,” Lockley said. “They say, ‘Look, I can make a nest.’ And if a female is watching, they make another and another.”

Dozens of scrapes would send the female dinosaurs swooning until mating took place and a real nest was built.

“When we first realized that they were mating evidence, my first thought was, ‘This is going to be big,’ ” said Lockley, who has been at CU Denver for 35 years. “It’s dinosaurs and sex. What a combo.”

Flowers and a box of chocolates? Hardly.

The scrapes, Lockley said, are very deep, narrow grooves, with a claw mark on the end.

These etchings of courtship, which come in pairs, can be as large as bathtubs.

The markings have been found at Dominguez-Escalante National Conservation Area, Gunnison Gorge National Conservation Area, areas around Montrose, and Dinosaur Ridge, just south of Lakewood, said Harley Armstrong, the Bureau of Land Management’s state and regional paleontologist.

“The reason it’s a big deal is that these kinds of scrapes have never been found ever in the world,” Lockley said, “but that didn’t stop scientists from speculating.”

Many researchers long believed dinosaurs were trying to attract one another, but there was no physical evidence of the prehistoric courtship until Lockley unearthed his two years of research.

“Not only have we found the scrape marks — like dinosaur foreplay,” Lockley said, “but we found 50 or 60 of these things, and these sites are what have been called display arenas where they play out their display activity and then go and nest.”

Because the marks were unable to be removed from the massive rock slabs without being damaged, 3-D images were created to document them. Rubber molds and fiberglass copies of the scrapes are being stored at the Denver Museum of Nature & Science.

The Lockley-led study appears Thursday in the journal Scientific Reports.

“I think it’s wonderful,” Armstrong said. “It’s another feather for Colorado’s fossil cap. Because we have some of the known dinosaur fossils, the world has been coming to our doorsteps since 1877.”

Lockley looks forward to finding more scratches and ones that existed more than 100 million years ago.

“It wouldn’t surprise me at all after publishing this article that there are people in Europe, South America, Asia that go, ‘Oh, we have those. We just didn’t know what they were,'” Lockley said.

Nicolas Cage’s stolen tyrannosaur skull back to Mongolia


This video from the USA says about itself:

Smuggled dinosaur fossils found by US authorities

11 July 2014

US authorities have found over 18 smuggled dinosaur fossils, including two Tyranosaurus bataar skeletons. They’ve agreed to send them back to Mongolia. Report by Simon Longden.

From Reuters:

Mon Dec 21, 2015 9:52pm EST

Actor Nicolas Cage returns stolen dinosaur skull he bought

NEW YORK | By Joseph Ax

Hollywood actor Nicolas Cage has agreed to turn over a rare stolen dinosaur skull he bought for $276,000 to U.S. authorities so it can be returned to the Mongolian government.

The office of Preet Bharara, the U.S. attorney in Manhattan, filed a civil forfeiture complaint last week to take possession of the Tyrannosaurus bataar skull, which will be repatriated to Mongolia.

The lawsuit did not specifically name Cage as the owner, but Cage’s publicist confirmed that the actor bought the skull in March 2007 from a Beverly Hills gallery, I.M. Chait.

The “National Treasure” actor is not accused of wrongdoing, and authorities said he voluntarily agreed to turn over the skull after learning of the circumstances.

Alex Schack, a publicist for Cage, said in an email that the actor received a certificate of authenticity from the gallery and was first contacted by U.S. authorities in July 2014, when the Department of Homeland Security informed him that the skull might have been stolen.

Following a determination by investigators that the skull in fact had been taken illegally from Mongolia, Cage agreed to hand it over, Schack said.

Cage outbid fellow movie star Leonardo DiCaprio for the skull, according to prior news reports.

The I.M. Chait gallery had previously purchased and sold an illegally smuggled dinosaur skeleton from convicted paleontologist Eric Prokopi, whom Bharara called a “one-man black market in prehistoric fossils.”

The Chait gallery has not been accused of wrongdoing. A representative did not return a request for comment on Monday.

It was unclear whether the Nicolas Cage skull was specifically connected to Prokopi, who pleaded guilty in December 2012 to smuggling a Tyrannosaurus bataar skeleton out of Mongolia‘s Gobi desert and was later sentenced to three months in prison.

As part of his guilty plea, Prokopi helped prosecutors recover at least 17 other fossils.

Assistant U.S. Attorney Martin Bell, who prosecuted Prokopi, was also the lead government lawyer in the Cage case, according to court records.

The Tyrannosaurus bataar, like its more famous relative Tyrannosaurus rex, was a carnivore that lived approximately 70 million years ago. Its remains have been discovered only in Mongolia, which criminalized the export of dinosaur fossils in 1924.

Since 2012, Bharara’s office has recovered more than a dozen Mongolian fossils, including three full Tyrannosaurus bataar skeletons.

“Each of these fossils represents a culturally and scientifically important artifact looted from its rightful owner,” Bharara said last week.

(Reporting by Joseph Ax; Editing by Andrew Hay and Leslie Adler)