Dinosaur age caecilian amphibian ancestor discovered?


This video says about itself:

19 June 2017

A new analysis of a pair of tiny fossils found in the 1990s has helped scientists to uncover the backstory of the most mysterious amphibian alive. Researchers used 3D X-rays to map out the remains of a now-extinct species that walked the Earth [220] million years ago. They found that the species is a long-missing amphibious link that expands the known history of frogs, toads and salamanders by at least 15 million years. Chinlestegophis jenkinsi (artist’s impression) was a tiny subterranean carnivore.

From Science News:

New fossils shake up history of amphibians with no legs

Tiny skulls and other bits hint at unexpected backstory for today’s snake-shaped caecilians

by Susan Milius

3:30pm, June 19, 2017

Newly named fossils suggest that a weird and varied chapter in amphibian deep history isn’t totally over.

Small fossils about 220 million years old found along steep red slopes in Colorado represent a near-relative of modern animals called caecilians, says vertebrate paleontologist Adam Huttenlocker of the University of Southern California in Los Angeles.

Caecilians today have long wormy bodies with either shrunken legs or none at all. Yet the nearly 200 modern species of these toothy, burrow-dwelling tropical oddballs are genuine amphibians. The fossil creatures, newly named Chinlestegophis jenkinsi, still had legs but could be the oldest known near-relatives of caecilians, Huttenlocker and colleagues suggest.

A popular view of the amphibian family tree has put caecilians on their own long, peculiar branch beside the ancient frogs and salamanders. But a close look at the new fossils suggests a much earlier split from ancestral frogs and salamanders, the researchers propose June 19 in Proceedings of the National Academy of Sciences. The move puts the caecilians into “a strange but incredibly diverse” group, the stereospondyls, Huttenlocker says. These species included elongated, short-legged beasts with heads shaped like toilet lids.

Among the many stereospondyls, Huttenlocker speculates that caecilians came from “an aberrant branch of miniaturized forms that went subterranean.” And today’s legless burrowers could be this once-flourishing group’s sole survivors.

Brazilian mammal-like reptile fossils, new study


This video from the USA says about itself:

Lecture 65: Cynodonts: Between Reptile and Mammal

8 November 2016

In this video we will list the major innovations in the cynodonts leading toward the origin of modern mammals.

From ScienceDaily:

Brazilian carnivorous mammal-like reptile fossil may be new Aleodon species

Brazilian specimens previously thought to be Chiniquodon may be first non-African Aleodon

June 14, 2017

Summary: Some Late Triassic Brazilian fossils of mammal-like reptiles, previously identified as Chiniquodon, may in fact be the first Aleodon specimens found outside Africa.

Some Late Triassic Brazilian fossils of mammal-like reptiles, previously identified as Chiniquodon, may in fact be the first Aleodon specimens found outside Africa, according to a study published June 14, 2017 in the open-access journal PLOS ONE by Agustín Martinelli from the Universidade Federal of Rio Grande do Sul, Brazil, and colleagues.

Aleodon is a genus of probainognathian cynodont, a taxon which evolved in the Triassic period, co-existed with dinosaur precursors and other archosaurs and eventually gave rise to mammals. The Aleodon genus was first described using fossils from Tanzania and Namibia, but it was not clear if it belonged within the family of carnivorous mammal-like reptiles known as Chiniquodontids, which includes the morphologically similar Chiniquodon.

The authors of the present study examined the skulls, jaws and teeth of Middle-Late Triassic fossil specimens from the Dinodontosaurus Assemblage Zone in Rio Grande do Sul, Brazil, most of which were previously thought to be Chiniquodontids, and compared them to a known African Aleodon species, A. brachyrhamphus.

The researchers used tooth morphology to identify one of the specimens as a new Aleodon species, which they named A. cromptoni after Dr Alfred “Fuzz” Crompton, who described the Aleodon genus. They also identified as Aleodon seven Brazilian specimens, previously thought to be chiniquodontids or traversodontids, and possibly one Namibian specimen, noting that this may call the reliability of Chiniquodon identification into question. Phylogenetic analysis indicated that Aleodon cromptoni may be, as suspected, a species in the Chiniquodonidae family.

Whilst the analysis was limited by the partial nature of some of the specimens, the authors note that the identification of these Late Triassic Aleodon specimens in Brazil strengthens the correlation between probainognathians from this epoch in South America and in Africa.

‘Paleontological’ football club in Winterswijk


This 18 August 2015 video is about a match in the Dutch football cup competition between two clubs from Winterswijk: FC Winterswijk and FC Trias.

FC Trias got its name because it is a fusion of three earlier clubs.

However, the club grounds are also not far from the Winterswijk quarry. Where muschelkalk stone from the Triassic, over 200 million years ago, is mined. The Triassic got its name from its three distinct rock layers. The Dutch word for Triassic is Trias. In the Winterswijk quarry, recently, a Triassic beetle was discovered; and,earlier, Triassic marine reptiles.

Triassic beetle discovery in Dutch Winterswijk


This video from the USA says about itself:

New Evidence Connects Dung Beetle Evolution to Dinosaurs

4 May 2016

Dr. Nicole Gunter, invertebrate zoology collections manager at The Cleveland Museum of Natural History, discusses research that uncovered an evolutionary connection between dinosaurs and dung beetles. The findings place the origin of dung beetles in the Lower Cretaceous period, with the first major diversification occurring in the middle of the Cretaceous.

By Janene Pieters on April 25, 2017 – 12:25:

A very rare fossil of a beetle that lived in the Netherlands 200 million years ago was found in a quarry in Winterswijk, according to a scientific publication in Paläontologische Zeitschrift written by paleontologists from Utrecht University,

From Paläontologische Zeitschrift:

New fossil insects from the Anisian (Lower to Middle Muschelkalk) from the Central European Basin (Germany and The Netherlands)

22 April 2017

Abstract

The Palaeozoic–Mesozoic transition is characterized not only by the most massive Phanerozoic mass extinction at the end of the Permian period, but also its extensive aftermath and a prolonged period of major biotal recovery during the succeeding Middle to Late Triassic.

Particularly, Anisian insect species from units of the Lower to Middle Muschelkalk from the Central European Basin are rare.

The Anisian is from 247.2 million years ago until 242 million years ago. So, older than the ‘200 million years ago’ of the Janene Pieters article.

The specimens described here originated from the Anisian Wellenkalk facies (Lower Muschelkalk), Vossenveld Formation of the Winterswijk quarry, The Netherlands, and from the orbicularis Member (lowermost Middle Muschelkalk, Anisian) of Esperstedt near Querfurt (Saxony-Anhalt).

Thus, the described insect remains from Winterwijk and Esperstedt expand our knowledge about Middle Triassic terrestrial arthropod communities and their palaeodiversity. A new species of Chauliodites (C. esperstedti sp. nov) is introduced.

Triassic dinosaur predecessors, new research


This video says about itself:

Meet Teleocrater, a Croc-Like Early Dinosaur Relative

12 April 2017

A 245-million-year-old creature with crocodilian-like legs is an early relative of dinosaurs.

From Virginia Tech in the USA:

Early dinosaur cousin had a surprising croc-like look

Paleobiologist’s latest discovery of Teleocrater rhadinus has overturned popular predictions

April 12, 2017

Summary: Teleocrater and other recently discovered dinosaur cousins show that these animals were widespread during the Triassic Period and lived in modern day Russia, India, and Brazil. Furthermore, these cousins existed and went extinct before dinosaurs even appeared in the fossil record.

For decades, scientists have wondered what the earliest dinosaur relatives looked like. Most assumed that they would look like miniature dinosaurs, be about the size of a chicken, and walk on two legs.

A Virginia Tech paleobiologist’s latest discovery of Teleocrater rhadinus, however, has overturned popular predictions. This carnivorous creature, unearthed in southern Tanzania, was approximately seven to 10 feet long, with a long neck and tail, and instead of walking on two legs, it walked on four crocodylian-like legs.

The finding, published in the journal Nature April 12, fills a critical gap in the fossil record. Teleocrater, living more than 245 million years ago during the Triassic Period, pre-dated dinosaurs. It shows up in the fossil record right after a large group of reptiles known as archosaurs split into a bird branch (leading to dinosaurs and eventually birds) and a crocodile branch (eventually leading to today’s alligators and crocodiles). Teleocrater and its kin are the earliest known members of the bird branch of the archosaurs.

“The discovery of such an important new species is a once-in-a-lifetime experience,” said Sterling Nesbitt, an assistant professor of geosciences in the College of Science.

He and Michelle Stocker, a co-author and also an assistant professor of geosciences in the College of Science, will give a free public talk with the fossils at 7 p.m. Thursday, April 13, 2017 at the Virginia Tech Museum of Geosciences on the second floor of Derring Hall.

Teleocrater fossils were first discovered in Tanzania in 1933 by paleontologist F. Rex Parrington, and the specimens were first studied by Alan J. Charig, former Curator of Fossil Reptiles, Amphibians and Birds at the Natural History Museum of London, in the 1950s.

Largely because the first specimen lacked crucial bones, such as the ankle bones, Charig could not determine whether Teleocrater was more closely related to crocodylians or to dinosaurs. Unfortunately, he died before he was able to complete his studies. The new specimens of Teleocrater, found in 2015, clear those questions up. The intact ankle bones and other parts of the skeleton helped scientists determine that the species is one of the oldest members of the archosaur tree and had a crocodylian look.

Nesbitt and co-authors chose to honor Charig’s original work by using the name he picked out for the animal, Teleocrater rhadinus, which means “slender complete basin” and refers to the animal’s lean build and closed hip socket.

“The discovery of Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives,” said Nesbitt. “It also raises far more questions than it answers.”

“This research sheds light on the distribution and diversity of the ancestors of crocodiles, birds, and dinosaurs,” says Judy Skog, program director in the National Science Foundation’s Division of Earth Sciences, “and indicates that dinosaur origins should be re-examined now that we know more about the complex history and traits of these early ancestors.”

Teleocrater and other recently discovered dinosaur cousins show that these animals were widespread during the Triassic Period and lived in modern day Russia, India, and Brazil. Furthermore, these cousins existed and went extinct before dinosaurs even appeared in the fossil record.

The team’s next steps are to go back to southern Tanzania this May to find more remains and missing parts of the Teleocrater skeleton. They will also continue to clean the bones of Teleocrater and other animals from the dig site in the paleontology preparation lab in Derring Hall.

“It’s so exciting to solve puzzles like Teleocrater, where we can finally tease apart some of these tricky mixed assemblages of fossils and shed some light on broader anatomical and biogeographic trends in an iconic group of animals,” said Stocker.

Stocker and Nesbitt are both researchers with the Global Change Center at Virginia Tech. Other co-authors on the paper include: Richard J. Butler with the University of Birmingham; Martin D. Ezcurra with Museo Argentino de Ciencias Naturales; Paul M. Barrett with the Natural History Museum of London; Kenneth D. Angielczyk with the Field Museum of Natural History; Roger M. H. Smith with the University of the Witwatersrand and Iziko South African Museum; Christian A. Sidor with the University of Washington; Grzegorz Niedzwiedzki with Uppsala University; Andrey G. Sennikov with Borissiak Paleontological Institute and Kazan Federal Univeristy; and Charig.

The research was funded by the National Science Foundation, National Geographic Society, a Marie Curie Career Integration Grant, a National Geographic Society for Young Explorers grant, and the Russian Government Program of Competitive Growth of Kazan Federal University.

See also here.

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.