Dinosaur age mosasaurs, video


This 19 October 2018 video says about itself:

Mosasaurs 101 | National Geographic

Mosasaurs were Earth’s last great marine reptiles. Learn about the surprising places they’d hunt, how some species dwarfed even the Tyrannosaurus rex, and how key physical adaptations allowed these reptiles to become a prehistoric apex predator.

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Dinosaur age predatory fish discovery


This image shows a new piranha-like fish from Jurassic seas with sharp, pointed teeth that probably fed on the fins of other fishes. From the time of dinosaurs and from the same deposits that contained Archaeopteryx, scientists recovered both this flesh-tearing fish and its scarred prey. Credit: M. Ebert and T. Nohl

From ScienceDaily:

150-million-year old, piranha-like specimen is earliest known flesh-eating fish

October 18, 2018

Researchers reporting in Current Biology on October 18 have described a remarkable new species of fish that lived in the sea about 150 million years ago in the time of the dinosaurs. The new species of bony fish had teeth like a piranha, which the researchers suggest they used as piranhas do: to bite off chunks of flesh from other fish.

As further support for that notion, the researchers also found the victims: other fish that had apparently been nibbled on in the same limestone deposits in South Germany (the quarry of Ettling in the Solnhofen region) where this piranha-like fish was found.

“We have other fish from the same locality with chunks missing from their fins”, says David Bellwood of James Cook University, Australia. “This is an amazing parallel with modern piranhas, which feed predominantly not on flesh but the fins of other fishes. It’s a remarkably smart move as fins regrow, a neat renewable resource. Feed on a fish and it is dead; nibble its fins and you have food for the future.”

The newly described fish is part of the world famous collections in the Jura-Museum in Eichstätt. It comes from the same limestone deposits that contained Archaeopteryx.

Careful study of the fossilized specimen’s well-preserved jaws revealed long, pointed teeth on the exterior of the vomer, a bone forming the roof of the mouth, and at the front of both upper and lower jaws. Additionally, there are triangular teeth with serrated cutting edges on the prearticular bones that lie along the side of the lower jaw.

The tooth pattern and shape, jaw morphology, and mechanics suggest a mouth equipped to slice flesh or fins, the international team of researchers report. The evidence points to the possibility that the early piranha-like fish may have exploited aggressive mimicry in a striking parallel to the feeding patterns of modern piranha.

“We were stunned that this fish had piranha-like teeth,” says Martina Kölbl-Ebert of Jura-Museum Eichstätt (JME-SNSB). “It comes from a group of fishes (the pycnodontids) that are famous for their crushing teeth. It is like finding a sheep with a snarl like a wolf. But what was even more remarkable is that it was from the Jurassic. Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time. Sharks have been able to bite out chunks of flesh but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later.”

Or, so it had seemed.

“The new finding represents the earliest record of a bony fish that bit bits off other fishes, and what’s more it was doing it in the sea”, Bellwood says, noting that today’s piranhas all live in freshwater. “So when dinosaurs were walking the earth and small dinosaurs were trying to fly with the pterosaurs, fish were swimming around their feet tearing the fins or flesh off each other.”

The researchers call the new find a “staggering example of evolutionary versatility and opportunism.” With one of the world’s best known and studied fossil deposits continuing to throw up such surprises, they intend to keep up the search for even more fascinating finds.

Primate evolution, video


This 16 October 2018 video says about itself:

Purgatorius, a kind of mammal called a plesiadapiform, might’ve been one of your earliest ancestors. But how did we get from a mouse-sized creature that looked more like a squirrel than a monkey — to you, a member of Homo sapiens?

Pre-Cambrian sponges, world’s oldest animals discovered


This July 2013 video says about itself:

A number of sponge-like fossils occur in the fossil record, many of which were originally described as sponges. A few of these are presented here. Charles D. Walcott was one of the first paleontologists to get involved with many of these, some of which are found in very ancient strata of the Precambrian.

Walcott’s Atikokania was one of these, it’s now considered to be a pseudofossil (false fossil) much like the previously described Eozoon canadense (the so called “Dawn Animal of Canada”).

Sponges are an ancient group of animals; however, their presence before the Cambrian Period is questionable.

That was then. However, now …

From the University of California – Riverside in the USA:

Sponges on ancient ocean floors 100 million years before Cambrian period

Molecular fossil evidence

October 15, 2018

Researchers at the University of California, Riverside, have found the oldest clue yet of animal life, dating back at least 100 million years before the famous Cambrian explosion of animal fossils.

The study, led by Gordon Love, a professor in UCR’s Department of Earth Sciences, was published today in Nature Ecology & Evolution. The first author is Alex Zumberge, a doctoral student working in Love’s research group.

Rather than searching for conventional body fossils, the researchers have been tracking molecular signs of animal life, called biomarkers, as far back as 660-635 million years ago during the Neoproterozoic Era. In ancient rocks and oils from Oman, Siberia, and India, they found a steroid compound produced only by sponges, which are among the earliest forms of animal life.

“Molecular fossils are important for tracking early animals since the first sponges were probably very small, did not contain a skeleton, and did not leave a well-preserved or easily recognizable body fossil record”, Zumberge said. “We have been looking for distinctive and stable biomarkers that indicate the existence of sponges and other early animals, rather than single-celled organisms that dominated the earth for billions of years before the dawn of complex, multicellular life.”

The biomarker they identified, a steroid compound named 26-methylstigmastane (26-mes), has a unique structure that is currently only known to be synthesized by certain species of modern sponges called demosponges.

“This steroid biomarker is the first evidence that demosponges, and hence multicellular animals, were thriving in ancient seas at least as far back as 635 million years ago,” Zumberge said.

The work builds from a 2009 study by Love’s team, which reported the first compelling biomarker evidence for Neoproterozoic animals from a different steroid biomarker, called 24-isopropylcholestane (24-ipc), from rocks in South Oman. However, the 24-ipc biomarker evidence proved controversial since 24-ipc steroids are not exclusively made by demosponges and can be found in a few modern algae. The finding of the additional and novel 26-mes ancient biomarker, which is unique to demosponges, adds extra confidence that both compounds are fossil biomolecules produced by demosponges on an ancient seafloor.

The study also provides important new constraints on the groups of modern demosponges capable of producing unique steroid structures, which leave a distinctive biomarker record. The researchers found that within modern demosponges, certain taxonomic groups preferentially produce 26-mes steroids while others produce 24-ipc steroids.

“The combined Neoproterozoic demosponge sterane record, showing 24-ipc and 26-mes steranes co-occurring in ancient rocks, is unlikely attributed to an isolated branch or extinct stem-group of demosponges”, Love said. “Rather, the ability to make such unconventional steroids likely arose deep within the demosponge phylogenetic tree but now encompasses a wide coverage of modern demosponge groups.”

Pterosaurs video


This 12 October 2018 video says about itself:

Pterosaurs 101 | National Geographic

Pterosaurs were the first vertebrates to take to the skies. Learn about the anatomical features that made their flight possible, how large some of these creatures grew, and which species was named after a vampire legend.

Smallest Tylosaurus mosasaur fossil ever discovered


This 2015 video from Canada is called Blair Malazdrewich meets up with an 80 million year old Manitoba celebrity, Bruce the Mosasaur.

From ScienceDaily:

Smallest ever Tylosaurus fossil sheds light on species

October 12, 2018

The smallest Tylosaurus mosasaur fossil ever found has been revealed in a new study in the Journal of Vertebrate Paleontology and surprisingly it lacks a trademark feature of the species.

The fossil, likely to be that of a newborn, does not have the recognizable long snout typically seen in the species. The lack of this snout initially perplexed researchers, who struggled to identify which group of mosasaurs it belonged to.

After examining and comparing the fossil to young specimens of closely-related species, such as T. nepaeolicus and T. proriger which already had identifiable noses, researchers finally deemed it to be a young Tylosaurus.

Lead author Professor Takuya Konishi, of the Department of Biological Sciences at the University of Cincinnati said, “Having looked at the specimen in 2004 for the first time myself, it too took me nearly 10 years to think out of that box and realize what it really was — a baby Tylosaurus yet to develop such a snout.

For those 10 years or so, I had believed too that this was a neonate of Platecarpus, a medium-sized (5-6m) and short-snouted mosasaur, not Tylosaurus, a giant (up to 13m) mosasaur with a significantly protruding snout.”

The lack of snout in the baby specimen found suggests to researchers that the development of this feature happens extremely quickly, between birth and juvenile stage — something that previous studies on the species had failed to notice.

Konishi further commented, “Yet again, we were challenged to fill our knowledge gap by testing our preconceived notion, which in this case was that Tylosaurus must have a pointy snout, a so-called ‘common knowledge.’

As individual development and evolutionary history are generally linked, the new revelation hints at the possibility that Tylosaurus adults from much older rock units may have been similarly short-snouted, something we can test with future discoveries.”

The fragments found include a partial snout with teeth and tooth bases, partial braincase, and a section of upper jaw with tooth bases. From this, they can estimate the entire baby skull to have been around 30cm (1ft) in total.

Tylosaurus belong to one of the largest-known groups of mosasaurs, up to 13m long, the front 1.8 m of that body being its head. The baby, therefore, was about 1/6 the size of such an adult.

Michael J. Everhart, a Kansas native and a special curator of paleontology at the Sternberg Museum of Natural History, Hays, Kansas, found the tiny specimens in 1991 in the lower Santonian portion of the Niobrara Chalk, in Kansas, which are now housed at the museum. The paper was co-authored by Paulina Jiménez-Huidobro and Michael W. Caldwell of the University of Alberta, Canada.

Did prehistoric sea creatures called mosasaurs subdue prey by ramming them with their bony snouts like killer whales do today? Here.

Oldest flying squirrel fossil discovered


This video says about itself:

9 October 2018

At Can Mata Landfill (els Hostalets de Pierola, Catalonia, Spain), scientists discovered fossil remains of the oldest-known flying squirrel – Miopetaurista neogrivensis. Based on the reconstructions, researchers estimate a weigh between 1.1 and 1.6 kilos, length of almost one meter and a wingspan around 40 centimeters.

From eLife:

Oldest fossil of a flying squirrel sheds new light on its evolutionary tree

October 9, 2018

The oldest flying squirrel fossil ever found has unearthed new insight on the origin and evolution of these airborne animals.

Writing in the open-access journal eLife, researchers from the Institut Català de Paleontologia Miquel Crusafont (ICP) in Barcelona, Spain, described the 11.6-million-year-old fossil, which was discovered in Can Mata landfill, approximately 40 kilometers outside the city.

“Due to the large size of the tail and thigh bones, we initially thought the remains belonged to a primate“, says first author Isaac Casanovas-Vilar, researcher at the ICP. In fact, and much to the disappointment of paleoprimatologists, further excavation revealed that it was a large rodent skeleton with minuscule specialised wrist bones, identifying it as Miopetaurista neogrivensis — an extinct flying squirrel.

Combining molecular and paleontological data to carry out evolutionary analyses of the fossil, Casanovas-Vilar and the team demonstrated that flying squirrels evolved from tree squirrels as far back as 31 to 25 million years ago, and possibly even earlier.

In addition, their results showed that Miopetaurista is closely related to an existing group of giant flying squirrels called Petaurista. Their skeletons are in fact so similar that the large species that currently inhabit the tropical and subtropical forests of Asia could be considered living fossils.

With 52 species scattered across the northern hemisphere, flying squirrels are the most successful group of mammals that adopted the ability to glide. To drift between trees in distances of up to 150 metres, these small animals pack their own ‘parachute’: a membrane draping between their lower limbs and the long cartilage rods that extend from their wrists. Their tiny, specialised wrist bones, which are unique to flying squirrels, help support the cartilaginous extensions.

But the origin of these animals is highly debated. While most genetic studies point towards the group splitting from tree squirrels about 23 million years ago, some 36-million-year-old remains that could belong to flying squirrels have previously been found. “The problem is that these ancient remains are mainly teeth”, Casanovas-Vilar explains. “As the dental features used to distinguish between gliding and non-gliding squirrels may actually be shared by the two groups, it is difficult to attribute the ancient teeth undoubtedly to a flying squirrel. In our study, we estimate that the split took place around 31 and 25 million years ago, earlier than previously thought, suggesting the oldest fossils may not belong to flying squirrels.

“Molecular and paleontological data are often at odds, but this fossil shows that they can be reconciled and combined to retrace history”, he adds. “Discovering even older fossils could help to retrace how flying squirrels diverged from the rest of their evolutionary tree.”

An exceptional site in a rubbish dump

The Can Mata landfill holds a set of more than 200 sites ranging in age between 12.6 and 11.4 Ma (middle to late Miocene). In the last 20 years, excavations carried out by the ICP in Can Mata have led to the identification of more than 80 species of mammals, birds, amphibians and reptiles. A remarkable number of primate remains from the site have revealed three new species of hominoids, nicknamed ‘Pau’ (Pierolapithecus catalaunicus), ‘Laia’ (Pliobates cataloniae) and ‘Lluc’ (Anoiapithecus brevirostris). Various studies of mammal remains recovered from the site, including the current work in eLife, indicate the existence of a dense subtropical forest.