Why don’t have turtles tail spikes like stegosaurs?


This 2017 music video is called Ankylosaurus | Dinosaur Songs | Pinkfong Songs for Children.

From North Carolina State University in the USA:

Why don’t turtles still have tail spikes?

Researchers explain why tail weaponry is rare

January 17, 2018

Summary: In a study covering 300 million years of evolutionary history, researchers have found four necessary components to tail weapon development: size, armor, herbivory and thoracic stiffness.

We’re all familiar with those awesome armored giants of the Jurassic and Cretaceous periods — Stegosaurus and Ankylosaurus — and their amazing, weaponized tails. But why aren’t similar weaponized tails found in animals living today? In a study covering 300 million years of evolutionary history, researchers from North Carolina State University and the North Carolina Museum of Natural Sciences found four necessary components to tail weapon development: size, armor, herbivory and thoracic stiffness.

“Weapons like tail clubs and bony spikes are found only in a few extinct animals — such as ankylosaurs, glyptodonts (large extinct armadillos) and in some ancient turtle species,” says Victoria Arbour, former postdoctoral student at NC State, current postdoctoral fellow at the Royal Ontario Museum and corresponding author of a paper describing the research. “These same weapons just don’t occur in modern-day animals, and we wanted to know why they were so rare even in the fossil record.”

Study co-author Lindsay Zanno, professor of biological sciences at NC State and head of paleontology at the NC Museum of Natural Sciences, agrees, “We kicked off this study with a simple observation: most animal weapons used for combat are located on the most critical part of the body for survival, the head, as opposed to more expendable ones such as the tail. Why, we asked, wasn’t evolution producing more animals with weaponized tails, when this would seem to be far less dangerous?”

To answer this question, Arbour and Zanno looked at a data set of 286 amniote species, both living and extinct, to see if there were patterns that pointed to the evolution of three specific types of tail weapons: bony spikes, a stiff tail or a bony knob at the tip of the tail. Amniotes refer to backboned, four-legged reptiles and mammals, as well as birds.

In the case of bony tail weaponry, the researchers found the animals had four things in common. First, they were usually large, weighing over 200 pounds (or 100 kilograms) — about the weight of the glyptodonts that used to roam South America or a living mountain goat — or were over three feet (a meter) long.

Second, armor was key. Ancient turtles, armadillos and armored dinosaurs were covered in some sort of hard carapace or bony plated armor. Thoracic stiffness — referring to a body that doesn’t bend side to side easily, perhaps so that it could easily counteract the forces needed to swing a large clubbed or spiked tail — was also important. Finally, every animal in the fossil record that developed elaborate tail weaponry was an herbivore, or vegetarian.

“It’s rare for large herbivores to have lots of bony armor to begin with,” Arbour says, “and even rarer to see armored species with elaborate head or tail ornamentation because of the energy cost to the animal. The evolution of tail weaponry in Ankylosaurus and Stegosaurus required a ‘perfect storm’ of traits that aren’t seen in living animals, and this unique combination explains why tail weaponry is rare even in the fossil record.”

Zanno continues, “This study is an elegant example of how the fossil record can be used to better understand the world around us today.”

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Arkansas dinosaur tracks in the USA


This video from the USA says about itself:

Acrocanthosaurus atokensis was the largest meat eating dinosaur in North America of the early to mid Cretaceous period. The most complete specimen was discovered just 10 miles from the Museum of the Red River in Idabel and it is now the State Dinosaur of Oklahoma.

This video from 2011 includes interviews with one of the principal excavators, Cephis Hall and Dr. Kenneth Carpenter of the USU Eastern Prehistoric Museum, who with Dr. Phillip J. Currie in 2000 described the find. Also interviewed are: Henry Moy of the Museum of the Red River, Neil Larson of the Black Hills Institute, Kyle Davies of the Sam Noble Museum, and Michael Bergland of mnfx.com.

From the University of Arkansas, Fayetteville in the USA:

Digitally preserving important Arkansas dinosaur tracks

January 16, 2018

Scientists using laser-imaging technology have documented and digitally preserved the first known set of theropod dinosaur tracks in the state of Arkansas.

The tracks, discovered in 2011 in a working gypsum quarry near Nashville, Ark., have since been destroyed. But high-resolution digital scans taken over a period of two weeks in 2011 allowed a team of researchers to study the tracks and determine that they were made by Acrocanthosaurus, a large carnivorous dinosaur. The findings extended the known range of Acrocanthosaurus 56 miles east, to the western shore of an ancient inland sea.

“It actually confirms that the main genus of large theropods in North America was Acrocanthosaurus”, said Celina Suarez, an assistant professor in the Department of Geosciences who was part of the team that documented and studied the tracks. “It now has been found in Wyoming, Utah, Oklahoma, Arkansas and Maryland, a huge range.”

Results of the study were recently published in the journal PLOS ONE. Researchers also created a detailed, publicly accessible online map of the site and the tracks. Brian Platt, an assistant professor of geology from the University of Mississippi, led the study. Researchers from the University of Arkansas Center for Advanced Spatial Technology (CAST) provided the scanning equipment and expertise.

The Rush to Preserve the Site

After the tracks were discovered, researchers received a $10,000 Rapid Grant from the National Science Foundation to quickly document the site. The U of A’s vice provost for research and economic development and the J. William Fulbright College of Arts and Sciences provided matching grants, for a total of $30,000.

The mining company moved its operations to allow researchers a short window of time to document the find. Researchers used LiDAR, which stands for light detection and ranging, because traditional methods would have taken too long, said Suarez. “From a technical standpoint, it’s important that the ability to rapidly scan such a large area is available to paleontologists. It was invaluable for this project since we had such little time to work.”

The site had two different sized Acrocanthosaurus tracks, suggesting both adult and younger animals walked the ancient tidal flat about 100 million years ago, during the Cretaceous Period. It also contained tracks made by sauropods, long-necked plant-eating dinosaurs.

LiDAR uses a pulsed laser to measure distances to the earth in tiny increments, generating a data “point cloud” that is used to digitally recreate a physical space. In this case, the equipment was mounted on a lift over the site. By analyzing carbon and oxygen isotopes of the rock at the track surface, researchers determined that the track surface was indeed the surface that the animals stepped on, rather than an underlying layer that remained when the original surface eroded.

The digital reconstruction of the trackway site: http://trackways.cast.uark.edu/index.html

Dinosaurs, lies and truth


This video says about itself:

LIES About Dinosaurs You PROBABLY Still Believe!

8 January 2018

Check out these lies about dinosaurs you probably still believe! From the largest and most dangerous dinosaurs like Tyrannosaurus rex and Brontosaurus to smaller ones like velociraptors, here are the top 10 myths about dinos debunked!

New dinosaur species with ‘hummingbird’ colours


This 15 January 2018 video is called New ‘rainbow’ dinosaurs might have sparkled like a hummingbird.

From daily The Independent in Britain today:

Newly discovered ‘rainbow’ dinosaur had shiny, colourful feathers like a hummingbird

Microscopic analysis of 160 million-year-old fossil suggests prehistoric reptile had iridescent plumage similar to that found in some modern bird species

Josh Gabbatiss, Science Correspondent

A duck-sized dinosaur found in China had a head and chest covered in shiny feathers similar to those seen on hummingbirds.

The creature has been named Caihong juji, meaning “rainbow with the big crest” in Mandarin.

When palaeontologists analysed a fossil of the dinosaur, first discovered by a farmer in north-eastern China, they found evidence of brightly-coloured plumage.

Iridescent feathers, which are found on some modern bird species, have a metallic sheen and change colour when viewed from different angles, giving them a “rainbow-like” appearance.

“When you look at the fossil record, you normally only see hard parts like bone, but every once in a while soft parts like feathers are preserved and you get a glimpse into the past,” said Dr Chad Eliason, a bird researcher at The Field Museum in Chicago and one of the authors of the paper describing the dinosaur.

“The preservation of this dinosaur is incredible; we were really excited when we realised the level of detail we were able to see on the feathers.”

Their findings were published in the journal Nature Communications.

When Dr Eliason and his colleagues examined the preserved feathers under a microscope, they could see tiny imprints of cells called melanosomes.

Melanosomes are the cells that contain pigment and give animals their colour.

At around 160 million-years-old, the pigment in the cells had long since degraded, but the scientists were able to determine the dinosaur’s appearance based on the structure of the cells.

Comparison of the ancient melanosomes of the Caihong with modern bird species revealed close similarities with the cells responsible for the iridescent plumage seen in hummingbirds.

Iridescent feathers were found covering the dinosaur’s head and chest, as well as around the base of its tail.

The skull of the Caihong is similar to that of the Velociraptor, but it also has a bony crest in the middle of its head.

The discovery opens up questions about how iridescence first evolved.

It could be that the Caihong’s “rainbow” feathers were used to attract mates, just like modern peacocks use their colourful tails.

“I came out of the project with a whole different set of questions that I wanted answers to”, said Dr Eliason.

“When I open up a drawer full of birds in the Field Museum’s collections, now I want to know when those iridescent feathers first developed, and how.”

Marsupial fossil discovery in Australia


This 2016 video is called Extinct and Extant Australian Species.

From Palaeontologia Electronica:

Miminipossum notioplanetes, a Miocene forest-dwelling phalangeridan (Marsupialia; Diprotodontia) from northern and central Australia

ABSTRACT

Miminipossum notioplanetes represents a new Early/Middle Miocene family (Miminipossumidae) of phalangeridan possums recovered from the Two Trees Local Fauna from the Riversleigh World Heritage area in northwestern Queensland and the Kutjamarpu Local Fauna of the Tirari Desert in northern South Australia. Because of widespread convergence in key features of P3 and M1 among phalangeridan families, the interfamilial relationships of Miminipossumidae are uncertain. The age of the Kutjamarpu Local Fauna has been in doubt with estimates ranging from Late Oligocene to Middle Miocene. The new taxon raises to 15 the number of taxa in the Kutjamarpu Local Fauna that are shared with both Riversleigh’s Faunal Zone B (Early Miocene) and Riversleigh’s Faunal Zone C (Middle Miocene) assemblages.

Although there is relatively little biocorrelative support for the estimate of a Late Oligocene age, doubt remains about whether the age is more likely to be Early or Middle Miocene. In terms of palaeoenvironmental implications, because both Riversleigh’s Early and Middle Mio-cene assemblages have been concluded to have accumulated in temperate, wet, species-rich lowland forests, the same or similar Early/Middle Miocene palaeoenvironments may well have extended into central Australia at the time when the Kutjamarpu assemblage was accumulating.

Making a dinosaur ‘fossil’ in your own home


This 2017 video is called Massospondylus | Learn Dinosaur Facts | Dinosaur Cartoons for Children | I’m A Dinosaur.

From the University of the Witwatersrand in South Africa:

Print a 200-million-year-old dinosaur ‘fossil’ in your own home

CT-scan study makes it possible to 3-D print and study the skull of the dinosaur species Massospondylus that roamed South Africa 200 million years ago in your own home

January 12, 2018

The digital reconstruction of the skull of a 200-million-year-old South African dinosaur, Massospondylus, has made it possible for researchers to make 3D prints and in this way facilitate research on other dinosaurs all over the world.

Kimi Chapelle, a PhD student at the Evolutionary Studies Institute at the University of the Witwatersrand in Johannesburg, South Africa (Wits), has used the Wits MicroFocus CT facility to peer inside the skull of the dinosaur Massospondylus.

Chapelle was able to use the CT facility to rebuild every bone of Massospondylus’s cranium, and to even look at tiny features like nerves exiting the brain and the balance organs of the inner ear. Her research is published today in the open-access journal, PeerJ.

Along with the paper, which is open for anybody to download and read, a 3D surface file of the skull is available to be downloaded.

“This means any researcher or member of the public can print their own Massospondylus skull at home,” says Chapelle.

Massospondylus is one of the most famous dinosaurs from South Africa and was named in 1854 by the celebrated anatomist Sir Richard Owen. Fossils of Massospondylus have been found in many places in South Africa, including Golden Gate National Park, where James Kitching discovered fossil eggs and embryos in 1976. Surprisingly, the skull of Massospondylus has never been the focus of an in-depth anatomical investigation.

“I was amazed when I started digitally reconstructing Massospondylus’ skull, and found all these features that had never been described”, said Chapelle, “it just goes to show that researchers still have a lot to learn about South Africa’s dinosaurs.”

Some of the most interesting discoveries from the skull, which is described in Chapelle’s paper include:

  • details on how the inner ear and the middle ear contacted each other and what these looked like
  • Where the nerves connecting different parts of the skull to the brain were and which bones they went through
  • that replacement teeth don’t erupt in a specific pattern and are present on all teeth, and
  • that the bones that surround the brain in this specific fossil were not fully fused

“By comparing the inner ear to that of other dinosaurs, we can try and interpret things like how they held their heads and how they moved. You can actually see tiny replacement teeth in the bones of the jaws, showing us that Massospondylus continuously replaced its teeth, like crocodiles do, but unlike humans that can only do it once”, says Chapelle.

“Also, the fact that the bones of the braincase aren’t fully fused means that this particular fossil is that of an individual that is not fully grown yet. This allows us to understand how Massospondylus grew, how fast it grew and how big it could grow.”

Hundreds of Massospondylus fossils have been found in South Africa, ranging in size from hatchlings to adult. Chapelle is using CT technology to study these additional fossils for her PhD. “I’ll be using scans of other specimens to answer new questions,” said Chapelle, “for example, how did Massospondylus babies weighing less than 100g grow up to be half-tonne adults?”

“Students like Kimi have been able to use our CT facility to produce cutting-edge research like this” said Prof. Jonah Choiniere, the supervisor and co-author of the study, “and it’s changing the way we do dinosaur research.”

Big fossil bat discovery in New Zealand


This video says about itself:

Fossils Reveal Giant New Species of Burrowing Bat: Vulcanops jennyworthyae

11 January 2018

Paleontologists say they’ve found the fossilized remains of a new genus and species of bat that lived in New Zealand between 19 and 16 million years ago (Early Miocene epoch).

From daily The Independent in Britain:

Giant extinct burrowing bat unearthed in New Zealand by palaeontologists

Discovery highlights the diversity of life that has been lost from the island nation

Josh Gabbatiss, Science Correspondent

Thursday 11 January 2018 18:15 GMT

Palaeontologists have discovered teeth and bones belonging to an ancient species of burrowing bat.

The species, named Vulcanops jennyworthyae, inhabited New Zealand around 16 million years ago.

Burrowing bats are a unique group of mammals only found in New Zealand.

These animals not only fly, but crawl along the ground too, and are equipped with specialised claws that enable them to do so.

Vulcanops is the biggest burrowing bat ever found – although it still only weighed around 40 grams.

The finding was described in the journal Scientific Reports.

“Burrowing bats are more closely related to bats living in South America than to others in the south-west Pacific,” said Professor Sue Hand, the first author of the study describing the new species, and a palaeontologist at the University of New South Wales.

Specifically, Prof Hand said burrowing bats such as Vulcanops are related to vampire bats.

However, unlike its blood-feeding cousins, the teeth of this new species suggest it consumed plant material as well as small creatures.

The scientists said the discovery served as a reminder of the diversity of life that has been lost from New Zealand.

“These bats, along with land turtles and crocodiles, show that major groups of animals have been lost from New Zealand”, said study co-author Professor Paul Scofield, of Canterbury Museum.

“They show that the iconic survivors of this lost fauna – the tuataras, moas, kiwi, acanthisittid wrens, and leiopelmatid frogs – evolved in a far more complex community that hitherto thought.”

Many bats used to inhabit New Zealand, but climate fluctuations are thought to have led to the ultimate demise of all but two species, which still survive today.

While the nation is still home to a diverse array of bird species, the two remaining bats are the only mammals to still inhabit the island that were not introduced by humans.