Dinosaur-age reptile live birth discovery


This video says about itself:

9 September 2015

“Tanystropheus” was a 6 metre long reptile that dated from the Middle Triassic period. It is recognizable by its extremely elongated neck, which measured 3 metres long – longer than its body and tail combined. The neck was composed of 12–13 extremely elongate vertebrae. Fossils have been found in Europe, the Middle East and China. Complete skeletons of juvenile individuals are most abundant in the Besano Formation of Italy, dating to 232 million years ago during the middle Triassic period.

“Tribelesodon”, originally considered to be a pterosaur by Francesco Bassani in 1886, is now recognized as a junior synonym to “Tanystropheus“. The best-known species is “Tanystropheus longobardicus“. Other currently recognized species include “T. conspicuus” and “T. meridensis”.

Another junior synonym of “Tanystropheus” is “Procerosaurus”. Two specimens were initially identified as “Procerosaurus”: The first was described as “P. cruralis” by von Huene in 1902. The second was described by Antonin Fritsch in 1878 as a species of “Iguanodon“, and is a highly doubtful dinosaurian-like bit of bone from the Cenomanian of the Czech Republic. He reassigned the species to “Procerosaurus” in 1905 intending to erect it as a new genus, unaware that the genus name was already in use. George Olshevsky in 2000 substituted “Ponerosteus” for this species.

In 2002, fossils of a related genus, “Dinocephalosaurus“, were collected in marine Triassic deposits in southwestern China. This new creature was 2.7 metres long, 1.7 metres of which was its neck and head. The specimen was described in 2004.

From Discover magazine:

Mamma Mia! Fossil Is First Hint Of Live Birth In Ancient Reptile

By Gemma Tarlach | February 14, 2017 10:00 am

Here’s some egg-citing news: for the first time in the fossil record, researchers have discovered a specific type of marine reptile that was carrying an advanced embryo at time of death. Why is that interesting? Because the specimen is an archosauromorph, an early member of the same gang of vertebrates that includes dinosaurs as well as pterosaurs, birds and crocodiles, all of which we thought, based on previous evidence, were exclusively egg-layers. Today that changes.

Some 245 million years ago, Dinocephalosaurus was a marine reptile swimming around what’s now southwest China. Paleontologists have found other examples of this ridiculously long-necked animal, but this one in particular met her maker with a developmentally advanced embryo in her abdominal cavity — providing science with the first example of viviparity in an archosauromorph.

Viva Viviparity!

Aside from being a great weapon to have in your arsenal when playing Scrabble, viviparity just means giving birth to live young rather than oviparity (egg-laying).

Viviparity has evolved a number of times among vertebrates, from lizards to mammals, but has never before been seen in the archosauromorphs, a rather large group of animals that emerged about 260 million years ago and eventually evolved into archosaurs, more famously known as things like dinosaurs and pterosaurs, the great and diverse flying reptiles.

Birds and the various crocodilians (crocodiles, alligators, caimans, etc.) are the only archosaurs still wandering about, and all are oviparous.

Baby On Board…or Breakfast?

I can hear a few of my more cynical readers grumbling over their keyboards “how do we know this is an embryo and not just a cannibalistic snack?” Right back atcha with findings from the paper, which ruled out both cannibalism and superposition (the possibility the two were separate individuals that died at the same time and were fossilized one atop the other).

The case against superposition: The fossilized embryo is completely enclosed by the fossilized adult, which means it must have been inside Mom when she died.

The case against cannibalism is a little more complex, but stay with me. The embryo is oriented with its neck pointing forward. For these marine reptiles, however, prey is typically swallowed and digested head-first, or neck pointing backward. In fact, the researchers did find a partially digested fish in the same mama fossil, in her abdominal cavity (not the Reptowomb location of Junior’s fossil), that had been swallowed and was moving along her digestive system head-first.

Want more evidence? Okay. The embryosaurus was curled in the typical fetal position, there was no evidence of eggshell anywhere around the fossil, and its baby bones were well ossified, which means it was in an advanced developmental stage; egg-laying animals drop baby bombs in significantly earlier stages of development.

Babymaking, Reptile Style

Today’s study, published in Nature Communications, is the earliest evidence we’ve got of the whole babymaking process for archosauromoprhs by about 50 million years. And understanding the reproductive biology of these animals, including dinosaurs, furthers our knowledge of how they lived, and maybe even why they went extinct.

Researchers thought for a long time, given what they were seeing in the fossil record, that dinosaurs, birds and crocodilians laid eggs because there was something in their archosauromorph biology that prohibited live births.

(Fun fact about crocodilians in particular: it’s after the egg is laid, and based on the ambient temperature as it incubates, that the sex of the babycroc is determined. Obviously that’s different than in viviparous Dinocephalosaurus. Since its offspring developed at body temperature, the sex of an individual Dino-c must have been determined genetically as it is for humans and other viviparous sorts.)

Because we now know at least one species of archosauromorph gave birth to live offspring, it suggests the lack of viviparity in later archosaurs was an adaptation to their environment, or provided some advantage not yet identified. Or maybe the fossil of a viviparous archosaur is somewhere out there, just waiting to be found.

See also here.

New Triassic marine reptile species discovery


This 2012 video, in Italian, is about Lariosaurus valceresii and Lariosaurus balsami Triassic marine reptiles.

Translated from Dutch NOS TV:

Amateur paleontologist finds skull of prehistoric reptile

Today, 06:05

Never before the animal had been found in the Netherlands; Lariosaurus. Now a 4.5 centimeter skull of the flippered fish-eater has been found in a quarry in Winterswijk.

Amateur paleontologist Remco Bleeker was the lucky one who found the skull. Bleeker, in everyday life a concrete repairer, is pleased with the find. …

Bleeker brought the skull for examination to Germany, where it was found that it was a Lariosaurus.

Muschelkalk

In the quarry at Winterswijk Triassic limestone is extracted from rock layers from the Triassic geological period some 240 million years ago. In the quarry Bleeker also once found a peculiar fossil of a toothy marine animal. This fossil, which was seen by experts as a missing link was even named after him: the Palatodonta bleekeri.

The skull of the lariosaurus has been given the name of the hamlet where it was found. “The first is named after me. Now it was time to honor the quarry,” says Bleeker, who gave his find on loan to Museum TwentseWelle.

The name of the newly discovered species is Lariosaurus vosseveldensis; after Vosseveld hamlet.

See also here.

The scientific description of the new species is here.

New Triassic fossil fish discovery in the Netherlands


Saurichthys fossil from China

Translated from Leidsch Dagblad daily in the Netherlands:

Billfish in Naturalis museum

Leiden – Naturalis has acquired a fossil of a new species which must have lived 200 to 250 million years ago. The billfish-like fish (Saurichthys diannae) was found by amateur paleontologist Herman Winkelhorst in the quarry of Winterswijk.

By Wilfred Simons – 27-5-2016, 17:36 (Update 27-5-2016, 17:36)

At the time, that area was in a coastal zone of the Tethys sea. That these billfish used to live also just offshore in shallow water, is proven by the fact that their eyes pointed upwards.

Winkelhof [sic; Winkelhorst] discovered a “graveyard” of about thirty young fish of the newly discovered species. That indicates that the sea at Winterswijk may have been a breeding ground for young life, like the current Wadden Sea. The amateur paleontologist donated the fossil to Naturalis.

See also here.

Pre-dinosaur footprint discovery in Spain


This video about Spain is called Hiker gets the shock of his life after stumbling across 230 million-year-old [pre-]dinosaur footprint.

By Lee Moran:

Hiker Happens Upon Prehistoric Footprint Of 230-Million-Year-Old Reptile

The fossil features details of the dinosaur-like creature’s claw and skin.

05/03/2016 08:38 am ET

It’s a trek that they’ll never forget.

A hiker walking in hills near Barcelona, northeastern Spain, stumbled upon a fossilized footprint believed to belong to a reptile-like ancestor of the dinosaurs. The extinct creature, called Isochirotherium, roamed the Earth during the Middle Triassic period some 230 million years ago.

It’s the “best preserved print ever found in the Iberian Peninsula,” reports the Spanish news agency EFE.

Catalonia’s autonomous regional government confirmed the find on Monday. It was discovered near Olesa de Montserrat, 25 miles north of Barcelona, on Apr. 22.

Olesa de Montserrat town council made a plaster cast of the print, according to the local newspaper La Vanguardia. The regional Department of Culture’s archaeology and paleontology service is examining the fossilized print.

Eudald Mujal, a paleontologist at Barcelona’s Autonomous University, said it was “exceptionally well preserved” and even “retains details of claw and skin.”

He told The Local that the now Isochirotherium was part of the archosaur group of animals. They were “similar to crocodiles, of quadrupedal gait, but with longer limbs,” and a more erect posture Mujal, said. 

Dinosaur-age haramiyids, mammals or reptiles?


This video from the USA says about itself:

High-tech analysis of proto-mammal fossil clarifies the mammalian family tree

16 November 2015

3D Reconstruction of the jaw of Haramiyavia, one of the earliest known proto-mammals, clarifies the debate over when mammals evolved. The study, published in the Proceedings of the National Academy of Sciences on Nov 16, 2015, confirms previous suggestions that mammal diversification occurred in the Jurassic around 175 million years ago—more than 30 million years after Haramiyavia and other forerunners to mammals diversified in the Triassic.

From the New York Times in the USA:

Jawbone in Rock May Clear Up a Mammal Family Mystery

By KENNETH CHANG

NOV. 16, 2015

With technologies like CT scans and 3-D printing, a team of scientists reported on Monday that it had solved a mystery about the family tree of mammals that started with a single tooth a century and a half ago.

The tooth, found in Germany in 1847, was tiny and distinctive in shape — not quite reptile, not quite mammal. More fossils of that kind were found around Europe, but always just single teeth. Scientists named this group of animals haramiyids — Arabic for “trickster.”

The teeth were embedded in rocks as old as 210 million years, an era in which ancestors of the first mammals were evolving.

“These were some of the most enigmatic fossils for years,” said Neil H. Shubin, a professor of organismal biology and anatomy at the University of Chicago. “People didn’t know what they were at all.”

In the late 1980s, Dr. Shubin, then a graduate student, was part of a team led by Farish Jenkins, a Harvard paleontologist, that searched for fossils in East Greenland. “You’re looking for tiny teeth in this vast Arctic landscape,” Dr. Shubin said. “The words ‘needle in a haystack’ seem very appropriate.”

The researchers found one particularly intriguing specimen, which they named Haramiyavia. “Avia” is Latin for “grandmother” — this was the grandmother of the trickster.

After a couple of years of meticulously clearing away much of the limestone surrounding the fossil, they reported on part of the Haramiyavia jawbone, revealing that the animal was indeed a proto-mammal.

What was unclear was whether Haramiyavia was a direct part of the family tree of mammals — that would push the emergence of mammals back to more than 200 million years ago — or an evolutionary branch that split off before common ancestors of mammals emerged, the view of paleontologists who believe that the first mammals evolved 170 million to 160 million years ago.

About two years ago, Dr. Shubin decided to re-examine the slab of Greenland limestone that enveloped the Haramiyavia fossil. “We knew that there were more bones in the rock,” he said.

Clearing away more limestone would jeopardize the fragile fossil. Instead, Dr. Shubin and his colleagues placed it in CT scanners and saw a mostly complete jawbone and many of the teeth.

“This kind of work used to be unimaginable,” said Zhe-Xi Luo, another University of Chicago paleontologist who joined Dr. Shubin on the new analysis.

Their conclusion: Haramiyavia, and thus all haramiyids, were not mammals, but belonged to a more ancestral side branch.

The crucial evidence they cite, reported Monday in the Proceedings of the National Academy of Sciences, is a trough in the lower jaw of Haramiyavia. In mammals, the trough is absent, because two bones connected to the trough migrated to the middle ear to form part of the three-bone hearing mechanism. (Birds and reptiles have only one bone in their middle ears.)

“This thing had a very primitive ear,” Dr. Shubin said. “That is the piece that is sort of the smoking gun.”

From the scans of the jaw and the teeth, the researchers created three-dimensional enlargements of the fossils, studying them like puzzle pieces to see how they fit together. Haramiyavia, a few inches long and rodentlike in appearance, ate plants by grinding leaves between broad teeth.

One argument that haramiyids were mammals was the similarity of the teeth to those of later animals known as multituberculates that were unquestionably mammals. But Dr. Shubin said the explanation instead was that the similar tooth characteristics evolved independently.

Timothy Rowe, a professor of geology at the University of Texas at Austin who was not involved in the new research, praised the work. “They really stepped out and squeezed every last bit of information that they could from these fossils,” he said. “What a relief after all these years to see a very compelling case made for exactly where haramiyids fit on the family tree.”

Dr. Rowe said there was no longer evidence that the earliest divergence of mammals occurred during the Triassic Period more than 200 million years ago. “The oldest date that’s based on real evidence is 30 or 40 million years younger than that,” he said. “It helps more accurately calibrate the mammalian tree of life.”

Not everyone agrees. “It’s a very great work, but I don’t think I’m totally convinced that is the case,” said Jin Meng, the curator of fossil mammals at the American Museum of Natural History in New York.

Dr. Meng is a member of a team that in the last couple of years has described more recent species of haramiyids that lived in China about 160 million years ago. The well-preserved Chinese fossils, nearly complete, possessed the characteristics of true mammals, Dr. Meng and his colleagues said.

The mammalian characteristics include the absence of a jawbone trough, Dr. Meng said in an interview. “If we accept the conclusion of this study, many of those mammalian structures must have evolved independently,” he said. “I still think the other hypotheses remain alive.”

Biggest ever Swiss dinosaur skeleton discovered


This video is called My Plateosaurus Tribute + my favorite Plateosaurus Pictures!

From swissinfo in Switzerland:

Triassic park: oldest Swiss dinosaur skeleton found

July 1, 2015 – 18:55

The largest dinosaur skeleton ever found in Switzerland has been uncovered in a clay pit in northern Switzerland. The eight-metre skeleton of a plateosaurus is thought to have been around 25 years old when it died.

“This herbivore lived 210 million years ago and was discovered in the Upper Triassic geologic layer,” said Ben Pabst, who has been leader of the dig in Frick, canton Aargau, since 1976. The dinosaur’s head has yet to be found.

Plateosaurus was a bipedal herbivore with a small skull on a long, mobile neck, sharp but plump plant-crushing teeth, powerful hind limbs, short but muscular arms and grasping hands with large claws on three fingers, possibly used for defence and feeding.

Unusually for a dinosaur, instead of having a fairly uniform adult size, fully grown individuals ranged from 4.8-10 metres long and weighed 600-4,000 kilograms.

The site in Frick is known around the world for the density of dinosaur skeletons.

“We have here an unbelievably large site. So far we have been able to determine an area with a diameter of three kilometres,” Pabst explained on Wednesday, adding that one hectare will yield some 500 animals and that for every 100 herbivore dinosaurs there is one carnivore.

Museum

Around 210 million years ago, Frick was flat, very hot, tropical and criss-crossed with rivers. Pabst assumes that at various times a range of dinosaurs, which weighed several tons, got stuck in the boggy land and died of thirst.

Since many complete skeletons of legs have been found, he believes the animals were mummified by the heat.

The theory that the dinosaurs sank in mud was strengthened by the fact that the plateosaurus in question was found with its legs spread.

The Frick site has an annual budget of CHF50,000 ($52,800) and the work is heavily reliant on volunteers. The latest find is too big for the Frick dinosaur museum, so a renovation is being considered.

Triassic turtle evolution, new research


This video says about itself:

Evolution of the Turtle Shell (Illustrated)

30 May 2013

Evolution of the turtle shell based on developmental and fossil data. This animation is based on the work of Dr. Tyler Lyson, currently at the Smithsonian Institution.

The animation shows how various fossils, particularly Eunotosaurus and Odontochelys, bridge the morphological gap between a generalized animal body plan to the highly modified body plan found in living turtles.

The paper, published in Current Biology, can be found here.

Animation by Stroma Studios.

From the Washington Post in the USA:

How the turtle got its shell, a not-so ‘Just So’ story

By Sarah Kaplan

June 25 at 5:22 AM

Long, long ago, in a time so far in the past it preceded the dinosaurs and the continents, lived a tiny creature named “grandfather turtle.” It had many of the qualities of the turtles we know and love today: a boxy body, plodding legs, a long neck topped by a small, round head.

It was only missing one thing: a shell.

Thanks to the newly discovered fossil of that tiny creature, scientists say they have solved the story of how the turtle got its shell. But this is no Rudyard Kipling fable. It’s science.

The not-so “Just So” story, published in the journal Nature on Wednesday, tracks the evolution of the turtle body plan through millions of years of history. By examining fossils that spanned millennia and continents, researchers were able to figure out how the modern turtle’s unique shell evolved from what was just a brief expanse of belly bones about 240 million years ago.

The origin of the turtle shell has long bewildered scientists (this was, apparently, the one natural phenomenon Kipling hadn’t written a story to explain). Though they had fossils of turtle predecessors from the beginning and the end of the Triassic period, there was little evidence of what happened to ancient turtles during the intervening years. The bones of the 260 million-year-old Eunotosaurus, a reptilian creature found in South Africa, had wide, flat ribs and a sprawling, turtle-like figure, but it was far from the armor-encased animal we know today.

The next time a turtle ancestor popped up in the fossil record, the Odontochelys about 220 million years before present, it had a fully developed belly plate called a “plastron” that would eventually expand to enclose the turtle’s whole body, protecting it from attacks from above and below. (The first turtle with a true shell wouldn’t appear on the scene until about 6 million years after that.)

But there was nothing in the yawning 40 million-year void between the two ancient species to explain where that plastron came from.

“Hopefully we’ll find more,” Robert Reisz, a paleontologist at the University of Toronto, told National Geographic after the Odontochelys was first found in 2008. “We’re closing the gap, but there is still a big morphological gap between this turtle and its non-turtle ancestors.”

Enter Pappochelys, the hero of our story, ready and willing to fill that gap.

Pappochelys, whose name means “grandfather turtle,” lived about 240 million years ago in a warm sub-tropical lake, Hans-Dieter Sues, a co-author of the Nature study and curator at the Smithsonian Museum of Natural History in D.C., told NPR. Discovered in a limestone quarry near Stuttgart, Germany, it is the precise chronological and morphological midpoint between the two previously known fossils: about eight inches from tip to tail, it had slender legs and an oddly boxy body with a rib cage that looked like the beginnings of a “little bony house.”

This physiological setup was good for protection and also worked as “bone ballast,” according to Smithsonian, allowing the animal to control its buoyancy in the water.

In addition, the Pappochelys had a series of hard, shell-like bones lining its belly — the beginnings of the plastron that would turn up 20 million years later.

“It has real beginnings of the belly shell developing, little rib-like structures beginning to fuse together into larger plates and then ultimately making up the belly shell,” Sues told NPR.

Sues’s co-author, Rainer R. Schoch, a paleontologist at the Staatliches Museum für Naturkunde in Stuttgart, called Pappochelys a “transitional creature,” one that illustrates how ancient lizards became modern turtles.

“Transitional creatures are the most important contribution that paleontology can make to the study of evolution,” Schoch told Voice of America. “They are often unexpected and show surprising features.”

And, in Pappochelys case, they tell pretty good stories.