Dinosaur age lizard footprints discovery


Scientists think that these fossilized footprints may represent the earliest evidence of a lizard running on two legs. Here, a front print (left) and a back print (right) are shown

By Helen Thompson, 1:19pm, February 15, 2018:

Fossil footprints may put lizards on two feet 110 million years ago

But the prints aren’t clear-cut, others say

Fossilized footprints from an iguana-like reptile provide what could be the earliest evidence of a lizard running on two legs.

The 29 exceptionally well-preserved lizard tracks, found in a slab of rock from an abandoned quarry in Hadong County, South Korea, include back feet with curved digits and front feet with a slightly longer third digit. The back footprints outnumber the front ones, and digit impressions are more pronounced than those of the balls of the feet. The lizard’s stride length also increases across the slab.

That’s what you’d expect to see in a transition from moseying along on four legs to scampering on two, says Yuong-Nam Lee, a paleontologist at Seoul National University who first came across the slab back in 2004. A closer examination two years ago revealed the telltale tracks.

Lee and his colleagues attribute the tracks to a previously unknown lizard ichnospecies, that is a species defined solely by trace evidence of its existence, rather than bones or tissue. Lee and his colleagues have dubbed the possible perpetrator Sauripes hadongensis and linked it to an order that includes today’s iguanas and chameleons in the Feb. 15 Scientific Reports.

Bipedal running certainly would have come in handy when escaping predatory pterosaurs some 110 million to 128 million years ago, the age of the rock slab. Lizard tracks are pretty rare in the fossil record, due to the reptiles’ lightweight bodies and penchant for habitats that don’t make great fossils. Though tracks appear in older fossils from the Triassic Epoch, 200 million to 250 million years ago, those prints belong to more primitive lizardlike reptiles. The new find edges out another set from the same region as the oldest true lizard tracks in the world by a few million years, the researchers say.

Plenty of modern lizards use two legs to scurry around. Some studies have linked similarities in ancient lizard bone structure to bipedal locomotion, but it is unclear exactly when lizards developed bipedalism. Lee’s team argues that these tracks represent the earliest and only direct evidence of bipedal running in an ancient lizard.

Martin Lockley, a paleontologist at the University of Colorado Denver who studies ancient animal tracks, points to alternative explanations. S. hadongensis might have trampled over front prints with its back feet, obscuring them and giving the appearance of two-legged running. Preservation can vary between back and front footprints. And the stride lengths aren’t quite as long as what Lockley says he’d expect to see in running. “Running or ‘leaping’ lizards make for a good story, but I am skeptical based on the evidence,” he adds.

So it may take the discovery of more fossilized lizard prints to determine whether S. hadongensis’ tracks truly represent running on two legs rather than simply scurrying on four.

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Bird, primate, alligator brains and intelligence


This video from the USA says about itself:

Bird Brain: Smarter Than You Think

13 June 2016

The first study to systematically measure the number of neurons in the brains of birds has found that they have significantly more neurons packed into their small brains than are stuffed into mammalian and even primate brains of the same mass.

From the University of Chicago Medical Center in the USA:

Birds and primates share brain cell types linked to intelligence

Bird and reptile brains have a vastly different anatomy from mammalian brains, but contain cell types linked to mammalian cognitive abilities

February 15, 2018

Summary: In a new study scientists show that some neurons in bird brains form the same kind of circuitry and have the same molecular signature as cells that enable connectivity between different areas of the mammalian neocortex. The researchers found that alligators share these cell types as well, suggesting that while mammal, bird and reptile brains have very different anatomical structures, they operate using the same shared set of brain cell types.

Neuronal cell types in the brains of birds linked to goal-directed behaviors and cognition are similar to cells in the mammalian neocortex, the large, layered structure on the outer surface of the brain where most higher-order processing takes place.

In a new study, published this week in the journal Current Biology, scientists from the University of Chicago show that some neurons in bird brains form the same kind of circuitry and have the same molecular signature as cells that enable connectivity between different areas of the mammalian neocortex. The researchers found that alligators share these cell types as well, suggesting that while mammal, bird and reptile brains have very different anatomical structures, they operate using the same shared set of brain cell types.

Birds are more intelligent than you think, and they do clever things. So, the question is: What kind of brain circuitry are they using?” said Clifton Ragsdale, PhD, professor of neurobiology at UChicago and senior author of the study. “What this research shows is that they’re using the same cell types with the same kinds of connections we see in the neocortex, but with a very different kind of organization.”

Both the mammalian neocortex and a structure in the bird brain called the dorsal ventricular ridge (DVR) develop from an embryonic region called the telencephalon. However, the two regions mature into very different shapes. The neocortex is made up of six distinct layers while the DVR contains large clusters of neurons called nuclei.

Because of this different anatomy, many scientists proposed that the bird DVR does not correspond to the mammalian cortex but is instead analogous to another mammalian brain structure called the amygdala.

In 2012, Ragsdale and his team confirmed a 50-year-old hypothesis by University of California San Diego neuroscientist Harvey Karten that proposed the DVR performs a similar function to the neocortex, but with dramatically different anatomy. In that study, the UChicago researchers matched genetic markers of the “input” and “output” neurons of the mammalian neocortex with genes expressed in several bird DVR nuclei.

In the new study, led by graduate student Steven Briscoe, the team found that other populations of neurons in the bird DVR share molecular signatures with neocortical intratelencephalic cells, or IT neurons. These IT neurons form a critical link in the circuitry of the neocortex. They help communicate between different neocortical layers and across cortical areas from one side of the brain to the other. The team then extended their work from birds to reptiles and identified IT neurons in a similar place in the alligator DVR.

“The structure of the avian DVR looks nothing like the mammalian neocortex, and this has historically been a huge problem in comparative neuroscience”, Briscoe said. “Anatomists have debated how to compare the DVR and neocortex for over a century, and our identification of IT neurons in the bird DVR helps to explain how such different brain structures can give rise to similar behaviors.”

The research suggests an interesting possibility that birds and primates evolved intelligence independently, developing vastly different brain structures but starting with the same shared sets of cell types.

“The input cell types, the output cell types and the intratelencephalic cell types are all conserved. They’re not just found in mammals, which we knew, but in non-avian reptiles like alligators and avian reptiles, or birds,” Ragsdale said. “It begins to clarify where and how in evolution we got this fantastic structure, the neocortex.”

Grass snakes survived Ice Age


This video from Britain says about itself:

GRASS SNAKE AND TWO ADDERS TOGETHER

THREE SNAKES TOGETHER WATCH THEM UNFURL BEFORE YOUR EYES,THIS IS NOT A COMMON SIGHT

These reptiles had been huddling together for warmth and are waking up.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Cool Snake – Warmth-loving Grass Snake survived the Ice Age in Central Europe

February 9, 2018

Using genetic analyses, Senckenberg scientists have discovered that not all Grass Snakes retreated to warm southern refugia during the last Central European Ice Age. Together with a colleague from Spain, they offer first evidence for the survival of a warmth-loving, egg-laying reptile during this cold period. The study was recently published in the journal Scientific Reports.

Among the warmth-loving reptiles, the Grass Snake is generally considered a “cool” representative: Its present distribution even extends to the Siberian permafrost soils and the area around the Finnish-Russian Lake Ladoga. “However, it came as a complete surprise to all of us that this thermophilic snake actually ‘overwintered’ in Central Europe during the Pleistocene Ice Age”, explains Professor Dr. Uwe Fritz, director of the Senckenberg Natural History Collections in Dresden.

Until now it had been assumed that thermophilic reptiles survived the Ice Ages only on the southern peninsulas of Europe and spread northward once the temperatures rose again during the Holocene and the interglacial periods. Using genetic methods, Fritz, his doctoral student Carolin Kindler, and their Spanish colleague, Eva Graciá now discovered that not all of the snakes, which are widespread across Europe today, retreated to warmer, Mediterranean regions.

The team examined a total of 1,372 genetic samples of these harmless reptiles. “We closely studied different genetic lineages of the Barred Grass Snake (Natrix helvetica) and the Eastern Grass Snake (Natrix natrix)”, explains Kindler and continues, “One of the lineages of Natrix natrix survived the Ice Age in two separate refugia: one was located in the Southern Balkans, the other — unexpectedly — in Central Europe.”

As evidence, the scientists from Dresden highlight the much higher genetic diversity — compared to their more southerly relatives — of the Grass Snakes in Northern Germany and Scandinavia.

“This means that we need to rethink the model of ‘southern warm refugia’ — areas of retreat in the Mediterranean region — during the Ice Ages. It is quite possible that other heat-loving animals also withstood the cold temperatures directly ‘at home'”, adds Fritz in summary.

Carboniferous-Permian plant extinction harmed amphibians, helped reptiles


This video says about itself:

30 March 2015

Dave and Palaeo After Dark’s James explore the Carboniferous forests in the ‘Carboniferous Forest Simulator‘!

This fantastic software is free for educational, museum or personal use. We really need to get our full support behind this project!

The programme, in its ‘alpha testing’ stage can be downloaded here.

Details of the development of the project can be found here.

From the University of Birmingham in England:

Rainforest collapse 307 million years ago impacted the evolution of early land vertebrates

February 7, 2018

Researchers at the University of Birmingham have discovered that the mass extinction seen in plant species caused by the onset of a drier climate 307 million years ago led to extinctions of some groups of tetrapods, the first vertebrates to live on land, but allowed others to expand across the globe. This research is published today (7th February 2018) in the journal Proceedings of the Royal Society B.

The Carboniferous and Permian periods (358 — 272 million years ago) were critical intervals in the evolution of life on land. During the Carboniferous Period North America and Europe lay in a single land mass at the equator which was covered by dense tropical rainforests. These rainforests flourished because of the warm humid climate, providing an ideal habitat for early tetrapods (vertebrates with four limbs), allowing them to diversify into a variety of species.

But towards the end of this period a major global environment change took place — just as the number of tetrapod species began to increase, the rainforests started to disappear. The climate became much drier causing the mass extinction of many species within the dominant plant groups, such as horsetails and club mosses. Despite this being a catastrophic event for plants, it has been unclear how this affected the early tetrapod community.

Previous attempts to estimate the diversity changes during this period have been hindered by the fossil record, which has not been sampled equally in different time intervals or geographic areas. To fill these gaps in the data, the Birmingham researchers compiled a new dataset from the Paleobiology Database and used advanced statistical methods to estimate diversity and biogeographic changes.

The results of the study show that tetrapod diversity decreased after the rainforest collapse and the onset of drier conditions, largely due to the reduction in suitable habitats for amphibians which needed wet environments to survive.

However they also found that after the rainforest collapse surviving tetrapod species began to disperse more freely across the globe, colonising new habitats further from the equator. Many of these survivors were early amniotes, such as early reptiles, whose generally larger size relative to early amphibians allowed them to travel longer distances, and their ability to lay eggs meant they were not confined to watery habitats.

Emma Dunne, from the University of Birmingham’s School of Geography, Earth and Environmental Sciences, said: ‘This is the most comprehensive survey ever undertaken on early tetrapod evolution, and uses many newly developed techniques for estimating diversity patterns of species from fossil records, allowing us greater insights into how early tetrapods responded to the changes in their environment.’

Dunne continued: ‘We now know that the rainiforest collapse was crucial in paving the way for amniotes, the group which ultimately gave rise to modern mammals, reptiles and birds, to become the dominant group of land vertebrates during the Permian period and beyond.’

Saving sick sea turtles


This video from the USA says about itself:

Sea Turtles Get Life-Saving Surgery at Florida Hospital | National Geographic

6 February 2018

The Turtle Hospital, a care and rehab center in the Florida Keys, has performed a recently developed treatment on two green sea turtles—an encouraging step in their fight against a pandemic disease.

Dinosaur age snakes, video


This video says about itself:

5 February 2018

90 million years ago, an ancient snake known as Najash had…legs. It is by no means the only snake to have limbs either. But what’s even stranger: we’re not at all sure where it came from.

Ichthyosaur discovery in England


This video says about itself:

New 200 Million-Year-Old Marine Reptile Discovered

26 June 2016

That was about the first Wahilisarus discovery. Now, there is a second one.

From the University of Manchester in England:

Rare ichthyosaur is only second known example

February 1, 2018

A rare 200 million-year-old ichthyosaur specimen has been discovered in a private collection 22 years after it was originally found.

The fossil is only the second example of Wahlisaurus massarae, a new species of ichthyosaur discovered by The University of Manchester palaeontologist, Dean Lomax. This fossil was originally found in 1996 and has now been donated to a museum.

Ichthyosaurs have recently been in the limelight as the focus of BBC One documentary, ‘Attenborough and the Sea Dragon’. They were a type of sea-going reptile that lived during the time of the dinosaurs. Their fossils are plentiful in the UK and in recent years Lomax has described five different species of the prehistoric reptile.

In 2016, Lomax described an ichthyosaur skeleton that he had examined in the collections of Leicester’s New Walk Museum and Art Gallery. He spotted several unusual features of the bones and determined that the features were unique and represented a new species, which he called Wahlisaurus massarae, in honour of two of his colleagues and mentors: Bill Wahl and Prof. Judy Massare.

He said: “When Wahlisaurus was announced, I was a little nervous about what other palaeontologists would make of it, considering the new species was known only from a single specimen. As a scientist you learn to question almost everything, and be as critical as you can be. My analysis suggested it was something new, but some palaeontologists questioned this and said it was just ‘variation’ of an existing species.”

In this new study, Lomax teamed up with Dr Mark Evans, palaeontologist and curator at the New Walk Museum, Leicester, and fossil collector, Simon Carpenter, of Somerset. The study focuses on a specimen Dean identified in Simon’s collection, which is an almost complete coracoid bone (part of the pectoral girdle) that has exactly the same unique features of the same bone in Wahlisaurus. The specimen was originally collected in 1996, in a quarry in northern Somerset. Once the specimen’s rarity was realised, Simon immediately donated it to Bristol Museum and Art Gallery.

Lomax added: “You can only imagine my sheer excitement to find a specimen of Wahlisaurus in Simon’s collection. It was such a wonderful moment. When you have just one specimen, ‘variation’ can be called upon, but when you double the number of specimens you have it gives even more credibility to your research.”

The new discovery is from a time known as the Triassic-Jurassic boundary, right after a world-wide mass extinction. For these reasons, the team have been unable to determine exactly whether the ichthyosaur was latest Triassic or earliest Jurassic in age, although it is roughly 200 million-year-old.

As part of the study, Dr Evans cleaned the bones and removed additional rock from the first specimen. This assisted in a detailed re-examination of the original skull, which led to the discovery of additional bones. This has provided a better understanding of the skull structure.

“The discovery of the new specimen in a private collection helps to recognise the important contribution of dedicated and responsible fossil collectors. I am especially grateful to Simon for donating the specimen and collecting all of the data available with the specimen when he found it”, added Lomax.

See also here.