Longest sauropod dinosaur trackway discovery


This video says about itself:

3 September 2012

Huge sauropods’ footprints from the late Jurassic plus tridactyls’ trackways – Plagne, French Jura…150 millions years ago!

From CNRS in France:

World’s longest sauropod dinosaur trackway brought to light

November 13, 2017

In 2009, the world’s largest dinosaur tracks were discovered in the French village of Plagne, in the Jura Mountains. Since then, a series of excavations at the site has uncovered other tracks, sprawling over more than 150 meters. They form the longest sauropod trackway ever to be found. Having compiled and analyzed the collected data, which is published in Geobios, scientists from the Laboratoire de Géologie de Lyon (CNRS / ENS de Lyon / Claude Bernard Lyon 1 University), the Laboratoire Magmas et Volcans (CNRS / Université Clermont Auvergne / Université Jean Monnet / IRD), and the Pterosaur Beach Museum conclude these tracks were left 150 million years ago by a dinosaur at least 35 m long and weighing no less than 35 t.

In 2009, when sauropod tracks were discovered in the French village of Plagne — near Lyon — the news went round the world. After two members of the Oyonnax Naturalists’ Society spotted them, scientists from the Paléoenvironnements et Paléobiosphère research unit (CNRS / Claude Bernard Lyon 1 University) confirmed these tracks were the longest in the world. Between 2010 and 2012, researchers from the Laboratoire de Géologie de Lyon supervised digs at the site, a meadow covering three hectares. Their work unearthed many more dinosaur footprints and trackways. It turns out the prints found in 2009 are part of a 110-step trackway that extends over 155 m — a world record for sauropods, which were the largest of the dinosaurs.

Dating of the limestone layers reveals that the trackway was formed 150 million years ago, during the Early Tithonian Age of the Jurassic Period. At that time, the Plagne site lay on a vast carbonate platform bathed in a warm, shallow sea. The presence of large dinosaurs indicates the region must have been studded with many islands that offered enough vegetation to sustain the animals. Land bridges emerged when the sea level lowered, connecting the islands and allowing the giant vertebrates to migrate from dry land in the Rhenish Massif.

Additional excavations conducted as late as 2015 enabled closer study of the tracks. Those left by the sauropod’s feet span 94 to 103 cm and the total length can reach up to 3 meters when including the mud ring displaced by each step. The footprints reveal five elliptical toe marks, while the handprints are characterized by five circular finger marks arranged in an arc. Biometric analyses suggest the dinosaur was at least 35 m long, weighted between 35 and 40 t, had an average stride of 2.80 m, and traveled at a speed of 4 km/h. It has been assigned to a new ichnospecies1: Brontopodus plagnensis. Other dinosaur trackways can be found at the Plagne site, including a series of 18 tracks extending over 38 m, left by a carnivore of the ichnogenus Megalosauripus. The researchers have since covered these tracks to protect them from the elements. But many more remain to be found and studied in Plagne.

1 The prefix ichno- indicates that a taxon (e.g., a genus or species) has been defined on the basis of tracks or other marks left behind, rather than anatomical remains like bones.

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‘Mammals nocturnal until dinosaur extinction’


This 2016 video says about itself:

Top 7 Prehistoric Mesozoic Mammals

Mesozoic Mammals. The first mammals on Earth. They lived among the giant dinosaurs (Mesozoic) but prevailed and evolved to control the planet and are our ancestors! Juramaia, the Jurassic mother, Repenomamus, the mammal that ate dinosaurs and much more!

From University College London in England:

Mammals switched to daytime activity after dinosaur extinction

November 6, 2017

Mammals only started being active in the daytime after non-avian dinosaurs were wiped out about 66 million years ago (mya), finds a new study led by UCL and Tel Aviv University‘s Steinhardt Museum of Natural History.

A long-standing theory holds that the common ancestor to all mammals was nocturnal, but the new discovery reveals when mammals started living in the daytime for the first time. It also provides insight into which species changed behaviour first.

The study, published today in Nature Ecology & Evolution, analysed data of 2415 species of mammals alive today using computer algorithms to reconstruct the likely activity patterns of their ancient ancestors who lived millions of years ago.

Two different mammalian family trees portraying alternative timelines for the evolution of mammals were used in the analysis. The results from both show that mammals switched to daytime activity shortly after the dinosaurs had disappeared. This change did not happen in an instant — it involved an intermediate stage of mixed day and night activity over millions of years, which coincided with the events that decimated the dinosaurs.

“We were very surprised to find such close correlation between the disappearance of dinosaurs and the beginning of daytime activity in mammals, but we found the same result unanimously using several alternative analyses,” explained lead author, PhD student Roi Maor (Tel Aviv University and UCL).

The team found that the ancestors of simian primates — such as gorillas, gibbons and tamarins — were among the first to give up nocturnal activity altogether. However, the two evolutionary timelines varied, giving a window between 52-33 mya for this to have occurred.

This discovery fits well with the fact that simian primates are the only mammals that have evolved adaptations to seeing well in daylight. The visual acuity and colour perception of simians is comparable to those of diurnal reptiles and birds — groups that never left the daytime niche.

“It’s very difficult to relate behaviour changes in mammals that lived so long ago to ecological conditions at the time, so we can’t say that the dinosaurs dying out caused mammals to start being active in the daytime. However, we see a clear correlation in our findings,” added co-author Professor Kate Jones (UCL Genetics, Evolution & Environment).

“We analysed a lot of data on the behaviour and ancestry of living animals for two reasons — firstly, because the fossil record from that era is very limited and secondly, behaviour as a trait is very hard to infer from fossils,” explained co-author, Professor Tamar Dayan (Chair of The Steinhardt Museum of Natural History, Tel Aviv University).

“You have to observe a living mammal to see if it is active at night or in the day. Fossil evidence from mammals often suggest that they were nocturnal even if they were not. Many subsequent adaptations that allow us to live in daylight are in our soft tissues.”

The team say further research is needed to better populate the mammalian family tree to give more accurate information on when the behaviour of species changes from night time to day time activity.

Dinosaur family tree not yet clear


Dinosaur family tree theories. Credit: Max Langer

From the University of Bristol in England:

Time to rewrite the dinosaur textbooks? Not quite yet!

November 1, 2017

The classification of the dinosaurs might seem to be too obscure to excite anyone but the specialists.

However, this is not at all the case. Recently, Matthew Baron and colleagues from the University of Cambridge proposed a radical revision to our understanding of the major branches of dinosaurs, but in a critique published today some caution is proposed before we rewrite the textbooks.

Every child learns that dinosaurs fall into two major groups, the Ornithischia (bird-hipped dinosaurs; Stegosaurus, Triceratops, Iguanodon and their kin) and the Saurischia (lizard-hipped dinosaurs; the predatory theropods, such as Tyrannosaurus, and the long-necked sauropodomorphs, including such well-known forms as Diplodocus).

Baron and colleagues proposed a very different split, pairing the Ornithischia with the Theropoda, terming the new group the Ornithoscelida, and leaving the Sauropodomorpha on its own.

This video says about itself:

The New Dinosaur Family Tree Explained

29 March 2017

You may have heard that dinosaur classification has been changed recently, and in this video I’ll explain what has happened and how this affects our views of dinosaurs overall.

The University of Bristol article continues:

Their evidence seemed overwhelming, since they identified at least 18 unique characters shared by ornithischians and theropods, and used these as evidence that the two groups had shared a common ancestor.

An international consortium of specialists in early dinosaurs, led by Max Langer from the Universidade de São Paulo, Brazil, and including experts from Argentina, Brazil, Germany, Great Britain, and Spain has now re-evaluated the data provided by Baron et al. in support of their claim.

Their results, presented today in the journal Nature, show that it might still be too early to re-write the textbooks for dinosaurs.

In this new evaluation, the authors found support for the traditional model of an Ornithischia-Saurischia split of Dinosauria, but also noted that this support was very weak, and the alternative idea of Ornithoscelida is only slightly less likely.

Max Langer said: “This took a great deal of work by our consortium, checking many dinosaurs on all continents first-hand to make sure we coded their characters correctly.

“We thought at the start we might only cast some doubt on the idea of Ornithoscelida, but I’d say the whole question now has to be looked at again very carefully.”

Baron and colleagues believed their data suggested that dinosaurs might have originated in the northern hemisphere, but the re-analysis confirms the long-held view that the most likely site of origin is the southern hemisphere, and probably South America.

Professor Mike Benton from the University of Bristol’s School of Earth Sciences, a member of the revising consortium, added: “In science, if you wish to overthrow the standard viewpoint, you need strong evidence.

“We found the evidence to be pretty balanced in favour of two possible arrangements at the base of the dinosaurian tree. Baron and colleagues might be correct, but we would argue that we should stick to the orthodox Saurischia-Ornithischia split for the moment until more convincing evidence emerges.”

Steve Brusatte of the University of Edinburgh, a member of the consortium, said: “Up until this year, we thought we had the dinosaur family tree figured out.

“But right now, we just can’t be certain how the three major groups of dinosaurs are related to each other. In one sense it’s frustrating, but in another, it’s exciting because it means that we need to keep finding new fossils to solve this mystery.”

Sinosauropteryx dinosaurs, new study


This video says about itself:

Dinosaur May Have Looked Like a Raccoon | National Geographic

30 October 2017

A new study of the Sinosauropteryx fossil may shed some light on its appearance and habitat.

Unusual herbivorous dinosaur discovery


This video says about itself:

op 26 October 2017

An ‘ugly’ dinosaur with huge scissor-style teeth that roamed the south of France 80 million years ago has been discovered by scientists.The plant eater – which grew to more than 16 feet long – had an unusually short face with powerful jaws that enabled it to snack on tough riverside palm trees.Its two-and-a-half inch teeth worked ‘like a pair of scissors’ as it chewed the hard foliage, before swallowing.

Matheronodon provincialis has been identified as a member of rhabdodontids – a group of herbivorous bipedal dinosaurs – from the late Campanian period about 84 to 72 million years ago. They were descendants of the iguanodontian dinosaurs from the Upper Jurassic.

By Helen Thompson, 4:00pm, October 26, 2017:

New dinosaur sported a curious set of chompers

Fossils discovered in France linked to previously unknown Cretaceous species

An ancient vegetarian dinosaur from the French countryside has given paleontologists something to sink their teeth into.

The most striking feature of a new species of rhabdodontid that lived from 84 million to 72 million years ago is its oversized, scissorslike teeth, paleontologist Pascal Godefroit, of the Royal Belgian Institute of Natural Sciences in Brussels, and his colleagues report October 26 in Scientific Reports. Compared with other dinos of its kind, Matheronodon provincialis’ teeth were at least twice as large but fewer in number. Some teeth reached up to 6 centimeters long, while others grew up to 5 centimeters wide. They looked like a caricature of normal rhabdodontid teeth, Godefroit says.

Of hundreds of fossils unearthed over the last two decades at a site called Velaux-La Bastide Neuve in the French countryside, a handful of jaw bones and teeth now have been linked to this new species, Matheronodon provincialis. The toothy dino belongs to a group of herbivorous, bipedal dinosaurs common in the Cretaceous Period. Rhabdodontids sported bladelike teeth, and likely noshed on the tough woody tissue parts of plants. Palm trees, common in Europe at the time, might have been on the menu.

Rhabdodontid teeth have ridges covered by a thick layer of enamel on one side and little to no ridges or enamel on the other. Teeth in the upper jaw have more ridges and enamel on the outer edge, while the reverse is true for bottom teeth. A closer look at the microstructure of M. provincialis’ teeth revealed an exaggerated version of this — many more ridges and lopsided enamel coating. Enamel typically protects from wear and tear, so chewing would have sharpened the dino’s teeth. “They operated like self-sharpening serrated scissors,” Godefroit says.

Big carnivorous dinosaur discovery in Lesotho


This 25 October 2017 video says about itself:

A dinosaur as big as a bus roamed southern Africa 200 million years ago, scientists have revealed thanks to the discovery of several huge three-toed footprints.

From the University of Manchester in England:

‘Mega-carnivore’ dinosaur roamed southern Africa 200 million years ago

October 25, 2017

An international team of scientists has discovered the first evidence that a huge carnivorous dinosaur roamed southern Africa 200 million year ago.

The team, which includes researchers from The University of Manchester, University of Cape Town, South Africa, and Universidade de São Paulo, Brazil, have found several three-toed footprints measuring 57cm long and 50cm wide.

This means the dinosaur would have an estimated body length of around nine metres (30 feet) and be a little less than three metres tall at the hip. That’s four times the size of a lion, which is currently the largest carnivore in southern Africa.

The footprints belong to a new species, named Kayentapus ambrokholohali, which is part of the group of dinosaurs called “megatheropod.” The term “Megatheropods” describes the giant two-legged carnivorous dinosaurs, such as the iconic Tyrannosaurus rex (T. rex) which fossil evidence shows was around 12 metres long.

This study, which is published in PLOS ONE, also reveals that these footprints make up the largest theropod tracks in Africa.

The tracks were found on an ancient land surface, known as a palaeosurface, in the Maseru District of Lesotho, a small country in southern Africa. The surface is covered in 200 million years old ‘current-ripple marks’ and ‘desiccation cracks’ which are signs of a prehistoric watering hole or river bank.

Dr Fabien Knoll, Senior Research Fellow at The University of Manchester, said: ‘The latest discovery is very exciting and sheds new light on the kind of carnivore that roamed what is now southern Africa.

‘That’s because it is the first evidence of an extremely large meat-eating animal roaming a landscape otherwise dominated by a variety of herbivorous, omnivorous and much smaller carnivorous dinosaurs. It really would have been top of the food chain.’

What makes the discovery even more important is that these footprints date back to the Early Jurassic epoch, when it was thought the size of most theropod dinosaurs was considerably smaller. On average they were previously thought to be around three to five metres in body length, with some records showing they may have reached seven metres at the very most. It is only much later in the Jurassic and during the Cretaceous, which starts 145 million years ago, that truly large forms of theropods, such as T. rex, appear in body and trace fossil records.

Dr Lara Sciscio, postdoctoral Research Fellow at the University of Cape Town, said: ‘This discovery marks the first occurrence of very large carnivorous dinosaurs in the Early Jurassic of southern Gondwana — the prehistoric continent which would later break up and become Africa and other landmasses. This makes it a significant find. Globally, these large tracks are very rare. There is only one other known site similar in age and sized tracks, which is in Poland.’

The ancient surface where these footprints were found is also covered with the tracks of much smaller theropod dinosaurs.

Dr Knoll added: ‘In South Africa, Lesotho, Zimbabwe and Namibia, there is good record of theropod footprints from the Late Triassic and Early Jurassic epochs. In fact, there are numerous palaeosurfaces where footprints and even tail and body impressions of these, and other animals, can be found. But now we have evidence this region of Africa was also home to a mega-carnivore.’

T. rex’s silly-looking arms were built for slashing. Robust bones and bearlike claws suggest the dino’s ridiculously small limbs were far from useless. By Carolyn Gramling. 3:30pm, October 25, 2017.

Cretaceous dinosaur discovery in Uzbekistan


This 2013 video is called Alvarezsaurus-the fast dino.

From PLOS ONE:

Alvarezsaurid dinosaur from the late Cretaceous found in Uzbekistan

Several distinctive bones identify this rare theropod

October 25, 2017

Bones from an Alvarezsaurid dinosaur were discovered in Uzbekistan and could shed light on the evolution and origin of the species, according to a study published October 25, 2017 in the open-access journal PLOS ONE by Alexander Averianov of Zoological Institute of the Russian Academy of Sciences, Russia and Hans-Dieter Sues of the Smithsonian Institution, USA.

Previous studies have described Alvarezsauridae as small, long-legged, bipedal dinosaurs with short forelimbs that featured bird-like hands. Since Alvarezsaurid remains are extremely rare, there is plenty to learn about the evolution of this species.

The authors of this study analyzed previously excavated Alvarezsaurid remains from the Turonian Bissekty Formation of Uzbekistan. They examined the vertebrae, the bird-like bone that fuses the wrist and knuckle known as the carpometacarpus, and pieces of what would be the fingers or toes, known as the phalanx. They then measured and compared the shapes and sizes of these bones with those from similar species from the literature.

The authors state that the characteristics for the Alvarezsaurid bones are so distinctive that it could be identified just from the seven bones collected at the Bissekty Formation. These distinctive features included rounded vertebrae located close to the tail, a large and depressed second metacarpal, and a robust second digit with a claw-like end.

While there are competing theories about where the Alvarezsaurid originated, the authors suggest that the discovery of an Alvarezsaurid at this site in Uzbekistan indicates that this group had an evolutionary history in Asia and provides evidence that this continent could have been where the clade originated.

Lead author Hans Sues says: “Our paper reports the discovery of the earliest known alvarezsaurid dinosaur from the Northern Hemisphere, based on 90-million-year-old fossils from Central Asia. Alvarezsaurids were unusual small predatory dinosaurs that had very short but powerfuly built arms that ended in a single large digit.”