Dimetrodon ancient reptile, new discoveries


This dimetrodon video is called Paleoworld- Tale Of A Sail (Part 1).

From Sci-News.com:

Dimetrodon Had Steak-Knife Teeth, Scientists Say

Feb 10, 2014

An international team of paleontologists suggests dimetrodon – a 4-m-long prehistoric reptile that lived during the early Permian period, between 295 million and 272 million years ago, and went extinct about 40 million years before the appearance of first dinosaurs – was the first terrestrial vertebrate to develop serrated ziphodont teeth.

Dimetrodon was the top of the terrestrial food chain in the early Permian and is considered to be the forerunner of mammals.

According to a new study reported in the journal Nature Communications, dimetrodons had a diversity of previously unknown tooth structures and were also the first terrestrial vertebrate to develop cusps – teeth with raised points on the crown, which are dominant in mammals.

The study also suggests ziphodont teeth were confined to later species of dimetrodon, indicating a gradual change in feeding habits.

“This research is an important step in reconstructing the structure of ancient complex communities,” said senior author Prof Robert Reisz from the University of Toronto Mississauga.

“Teeth tell us a lot more about the ecology of animals than just looking at the skeleton.”

“We already know from fossil evidence which animals existed at that time but now with this type of research we are starting to piece together how the members of these communities interacted.”

Prof Reisz and his co-author, Kirstin Brink from the University of Toronto Mississauga, studied the changes in dimetrodon teeth across 25 million years of evolution.

The analysis indicated the changes in tooth structure occurred in the absence of any significant evolution in skull morphology. This indicates a change in feeding style and trophic interactions.

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Niger Permian reptile fossil discovery


After the South African discovery of an early Triassic amphibian and a mammal-like reptile together … now a discovery from a few million years earlier, more to the north in Africa.

Bunostegos

From the BBC:

24 June 2013 Last updated at 19:02 GMT

A bizarre reptile with knobbly growths on its head roamed a vast, isolated desert about 260 million years ago, researchers say.

New fossils from northern Niger in Africa have been described in the Journal of Vertebrate Paleontology.

The distinctive creature belongs to a new genus of pareiasaur – plant-eating creatures that flourished during the Permian period.

The cow-sized specimen has been named Bunostegos, which means “knobby roof”.

During Permian times, the Earth was dominated by a single supercontinent called Pangaea.

Animal and plant life dispersed broadly across the land, as documented by identical fossil species found on multiple modern continents.

But the new research by an international team supports the idea that there was an isolated desert in the middle of Pangaea with distinctive animals.

Most pareiasaurs had bony knobs on their skulls, but Bunostegos sported the largest, most bulbous ones ever seen in this group, which were common in the Middle and Late Permian, about 266-252 million years ago.

In life, these were probably skin-covered horns like those on the heads of modern giraffes.

“We can’t say for sure, but it is most likely that the bony knobs on the skull of pareiasaurs did not serve a protective function,” Dr Linda Tsuji from the University of Washington in Seattle told BBC News.

“They vary quite markedly in size and shape between different species, with some species lacking prominent knobs entirely, so I think that they were purely ornamental. The most probable use was for inter-specific (between species) or intra-specific (within species) recognition.”

Dr Tsuji and colleagues performed an analysis showing that Bunostegos was actually more closely related to older and more primitive pareiasaurs.

This led them to the conclusion that its genealogical lineage had been isolated for millions of years.

Climatic conditions may have conspired to corral Bunostegos – along with several other reptiles, amphibians, and plants – and keep them constrained to the central, arid area of the supercontinent.

“Our work supports the theory that central Pangea was climatically isolated, allowing a unique relict fauna to persist into the Late Permian,” said Christian Sidor, another author of the paper.

This surprised the scientists because areas outside this central region show fossil evidence of regular faunal interchange.

Geological data show that central Pangaea was extremely dry, discouraging some animals from passing through, while keeping those within from venturing out.

The long period of isolation under these parched conditions gave Bunostegos lineage time to evolve its unique anatomical features.

Much of what was once central Pangaea remains to be explored by palaeontologists.

“It is important to continue research in these under-explored areas,” said Dr Tsuji.

“The study of fossils from places like northern Niger paints a more comprehensive picture of the ecosystem during the Permian era.”

See also here.

To Longyearbyen, Svalbard, Arctic


This video is about a plane landing at LYR airport, Longyearbyen, Svalbard, in May 2007.

2 June 2013.

I have been to the Antarctic.

But I had never been to the high Arctic so far. The closest I came were the Lofoten islands of Norway, and Iceland, both near the Arctic circle.

Now, however, to Svalbard. This Arctic archipelago is about halfway between northern Norway and the North Pole. Outside Norway, the islands are often called Spitsbergen; in Norwegian, the name of the largest island.

First, our plane went to Oslo, the capital of Norway.

After some hours waiting, we transferred to a smaller plane.

At 10pm, it passed the Arctic circle, flying near Bodø in northern Norway.

23:05: we pass Bear Island, about half way between Svalbard and continental Norway. Officially, Bear Island is the southernmost island of the Svalbard archipelago. It is uninhabited now, except for a meteorological station.

South western Spitsbergen from the air, 2 June 2013

Then, the plane reached the mountains of the west coast of Spitsbergen island.

South western Spitsbergen mountains from the air, 2 June 2013

This video is called Landing at Longyearbyen / Svalbard lufthavn (LYR) on 8 April 2009 on a flight from Ny-Ålesund.

Almost at midnight of 2 June, we landed at the airport of Longyearbyen, the capital (basically: the only sizable village) of Svalbard.

We drove from the airport to Longyearbyen village.

It is Arctic summer. So, the sun never sets now.

Svalbard is one of not so many countries where there has never been a visit to Dear Kitty. Some blog yet. Not that surprising: only 2,500 people live there, not all of them fanatical Internauts.

During the next days, there were will be photos of birds, other wildlife of Svalbard and other sides of Svalbard on this blog.

About Svalbard prehistory:

Bryozoans from the Lower Permian Treskelodden and Wordiekammen formations of southern and central Spitsbergen respectively, Svalbard, have been studied. Twenty species are identified, including one new genus, Toulapora gen. nov., with Toulapora svalbardense as type species and one new species, Ascopora birkenmajeri sp. nov. The taxonomic composition is typical Lower Permian, with species in common with Timan−Pechora and the Urals (Russia) and Ellesmere Island (the Canadian Arctic). Growth habits reflect a moderately to deeper shelf environment.

How turtles got their shells


Eunotosaurus africanus

By Roxanne Palmer:

Turtle Shell Origin Story Gets New Chapter Thanks To Fossil Reptile

May 30 2013 12:55 PM

Rudyard Kipling’s fanciful “Just So Stories” have offered explanations for how the leopard got his spots and how the camel got his hump. Kipling didn’t offer an origin story for the turtle’s shell, but scientists have now come to the rescue.

In a new paper published in the journal Current Biology, researchers led by Yale University and Smithsonian Institution researcher Tyler Lyson present the earliest evidence yet for how some ancient reptiles turned into swimming tanks.

The turtle’s shell is a unique specimen of evolution. Other animals with shells usually have ones made from bony scales on the outsides of their bodies – like the crocodile, whose skin is dotted with thick bony plates called osteoderms. But a turtle’s shell is made from the fusion of more than 50 bones, including parts of the pelvis, ribs and vertebrae.

To get a better picture of how the turtle shell was made, Lyson and his colleagues studied an ancient South African reptile called Eunotosaurus africanus, which hails from about 260 million years ago. Scientists have found fossils of other turtle ancestors, but these ones had either fully developed shells. In 2008, Chinese scientists uncovered the remains of the 220 million-year-old Odontochelys semitestacea, which had a complete shell on its belly side, but only a partially developed shell on the back. The new specimen goes back even earlier.

“Eunotosaurus neatly fills an approximately 30-55-million year gap in the turtle fossil record,” Lyson said in a statement. “There are several anatomical and developmental features that indicate Eunotosaurus is an early representative of the turtle lineage; however, its morphology is intermediate between the specialized shell found in modern turtles and primitive features found in other vertebrates.”

The fossil shares several characteristics with modern turtles, including broad ribs and a lack of intercostal muscles, which run between the ribs and which provide support and movement for the chest wall.

“The reason, I think, that more animals don’t form a shell via the broadening and eventually suturing together of the ribs is that the ribs of mammals and lizards are used to help ventilate the lungs,” Lyson says. “If you incorporate your ribs into a protective shell, then you have to find a new way to breathe!”

Since their shells don’t let modern turtles breathe by expanding and contracting their ribs, they have other methods. One part of the process is called “buccal pumping,” and it involves gulping air and pushing it into the lungs using movements of the throat. Turtles can also sometimes achieve a limited amount of respiration via the cloaca – hence the popular myth that turtles breathe through their rear ends. Some species of turtle have sacs called bursae on either side of the cloaca, with thin membranes that allow for gas exchange.

Most turtles don’t rely on their rear ends to breathe, but an Australian species called the Fitzroy River turtle has exploited this feature. This turtle can pump water in and out of the sacs near its cloaca and meet up to two-thirds of its oxygen needs this way.

Solving the mystery of how turtle breathing developed over time is the next research frontier for Lyson and his colleagues.

“It is clear that this novel lung ventilation mechanism evolved in tandem with the origin of the turtle shell,” he says.

SOURCE: Lyson et al. “Evolutionary Origin of the Turtle Shell.” Current Biology published online 30 May 2013.

Pre-dinosaur mesosaurs’ live birth


Despite the fact that the mesosaur embryos were dated to around 280 million years ago, researchers found them in a remarkably well preserved condition

From Discovery News:

Live Birth Predates Dinos

Analysis by Jennifer Viegas

Mon Dec 10, 2012 06:31 AM ET

Producing living young, and not external eggs, is a form of birth that could date back to 280 million years ago or even earlier, a new study suggests.

Called viviparity, this form of birth is used by humans, but clearly we were far from being the first to evolve it.

The study, published in the December issue of Historical Biology: An International Journal of Paleobiology, focuses on mesosaurs, which were among the world’s first aquatic reptiles. They lived in what are now South America and South Africa at a time when these two landmasses were united and part of the giant supercontinent Pangaea.

Mesosaurs, and even their earlier ancestors, possibly “were not able to produce hard shelled eggs, at least for the first several million years of their evolution,” lead author Graciela Piñeiro, a paleontologist at Uruguay‘s Facultad de Ciencias, told Discovery News. “After the recent discovery of mesosaur embryos, we can state with a high degree of confidence that embryo retention developed early in amniote evolution, given that mesosaurs are among the basal-most reptiles and that they date from the Early Permian around 280 million years ago.”

Piñeiro and colleagues Jorge Ferigolo, Melitta Meneghel and Michel Laurin recently discovered the exceptionally well-preserved mesosaur embryos at sites in Uruguay and Brazil. The environmental conditions at the locations allowed for the preservation of soft tissues, nerves and blood vessels, she said.

Giving birth in this manner and laying eggs each come with advantages and disadvantages. Eggs with hard, mineralized shells, such as those associated with today’s chicken eggs or those of dinosaurs, are believed to help reproduction on dry land. But many terrestrial animals, including humans, do not lay eggs, so there must be other benefits to viviparity.

“We think that the retention of the eggs may have appeared in amniotes as a useful strategy to avoid predation and increase survivorship chances for the embryos,” Piñeiro said.

Parental care often then follows. There is even some evidence that mesosaurs provided such care, because adults and juveniles have been associated together in the fossil record.

At least some mesosaurs even had the added challenge of giving birth and raising young in extremely salty water.

“In Uruguay, mesosaurs may have first colonized the shallow water environment of the Mangrullo Formation, which under the establishment of arid climatic conditions that increased evaporation became like a salty marsh where just a few opportunistic organisms could tolerate the anoxic bottom conditions generated by the accumulation of high amounts of organic matter,” Piñeiro explained.

When infant mesosaurs entered the world, they possibly even had a salt gland and other anatomical adaptations already in place, allowing them to survive the otherwise challenging conditions.

There is also compelling evidence that giant, carnivorous, four-flippered reptiles known as plesiosaurs gave birth to live young as well. Robin O’Keefe of Marshall University and team discovered a big embryonic marine reptile contained in the fossil of its 15.4-foot-long mother, which lived 78 million years ago.

“The embryo is very large in comparison to the mother,” O’Keefe said, “much larger than one would expect in comparison with other reptiles. Many of the animals alive today that give birth to large, single young are social and have maternal care. We speculate that plesiosaurs may have exhibited similar behaviors, making their social lives more similar to those of modern dolphins than other reptiles.”

Poem on fossil amphibian


There are not only songs on amphibians living today; there is also at least one poem about an amphibian which became extinct about 295 million years ago.

Poem on amphibian Eryops

From Discover Magazine:

Newly Unearthed Papers From Fossil Hunters Include An Ode to Bones

This poem in praise of the Permian amphibian Eryops was scrawled on the back of a label now in the American Museum of Natural History by Jacob Boll, a Swiss-German fossil hunter involved in a tumultuous 19th-century paleontology feud.

Graduate students and post-docs do a lot of important work in science these days, in the names of their more eminent supervisors, and there was a similar set-up in the early days of American paleontology. Many of the fossils named by and attributed to E.D. Cope and O.C. Marsh, archenemies and the era’s most prominent paleontologists, were collected in the field by hired hunters like Boll and his contemporary Robert T. Hill, who both worked for Cope.

Paleontologists sifting through papers in the library of Southern Methodist University recently came across letters between Hill and Cope and, while examining specimens at AMNH, happened on Boll’s little poem.

Here is a translation:

“Now you will with some few others
Trek to the professor’s seat.
Awakened through his careful thought,
Be reassembled from your fragments,
To tell to others yet to come
From the sculpting of your teeth
How you lived and disappeared,
Name you he will, and what he found.”

Watch this video about the Bone Wars, as Cope and Marsh’s feud was known, to hear the poem read aloud and learn more details about the trove of papers:

New fish evolution research


This video is called Animal Armageddon: Acanthodians.

From the University of Chicago Medical Center in the USA:

Where we split from sharks: Common ancestor comes into focus

The common ancestor of all jawed vertebrates on Earth resembled a shark, according to a new analysis of the braincase of a 290-million-year-old fossil fish that has long puzzled paleontologists.

New research on Acanthodes bronni, a fish from the Paleozoic era, sheds light on the evolution of the earliest jawed vertebrates and offers a new glimpse of the last common ancestor before the split between the earliest sharks and the first bony fishes — the lineage that would eventually include human beings.

“Unexpectedly, Acanthodes turns out to be the best view we have of conditions in the last common ancestor of bony fishes and sharks,” said Michael Coates, PhD, professor of organismal biology and anatomy at the University of Chicago and senior author of the study published in Nature. “Our work is telling us that the earliest bony fishes looked pretty much like sharks, and not vice versa. What we might think of as shark space is, in fact, general modern jawed vertebrate space.”

The group gnathostomes, meaning “jaw-mouths,” includes tens of thousands of living vertebrate species, ranging from fish and sharks to birds, reptiles, mammals and humans. Cartilaginous fish, which today include sharks, rays, and ratfish, diverged from the bony fishes more than 420 million years ago. But little is known about what the last common ancestor of humans, manta rays and great white sharks looked like.

Coates and colleagues Samuel Davis and John Finarelli found answers to this mystery in an unexpected place: the acanthodians, extinct fishes that generally left behind only tiny scales and elaborate suites of fin spines. But armed with new data on what the earliest sharks and bony fishes looked like, Coates and colleagues re-examined fossils of Acanthodes bronni, the best-preserved acanthodian species.

Davis created highly detailed latex molds of specimens revealing the inside and outside of the skull, providing a valuable new data set for assessing cranial and jaw anatomy as well as the organizations of sensory, circulatory and respiratory systems in the species.

“We want to explore braincases if possible, because they are exceptionally rich sources of anatomical information,” Coates said. “They’re much better than scales, teeth or fin spines, which, on their own, tend to deliver a confusing signal of evolutionary relationships.”

The analysis of the sample combined with recent CT scans of skulls from early sharks and bony fishes led the researchers to a surprising reassessment of what Acanthodes bronni tells us about the history of jawed vertebrates. These are various latex molds taken from the fossil of Acanthodes bronni.

“For the first time, we could look inside the head of Acanthodes, and describe it within this whole new context,” Coates said. “The more we looked at it, the more similarities we found with sharks.”

However, analysis of the evolutionary relationships of Acanthodes bronni — even with these new data added — still connected this species to early bony fishes. Meanwhile, some acanthodian species turned out to be primitive sharks, while others were relatives of the common ancestor of sharks and bony fishes.

This result explains some of the longstanding confusion about the placement of acanthodians in vertebrate history. But additional analyses went a step further. Using more than 100 morphological characters, the researchers quantified the mutual resemblance among the earliest jawed fishes. Acanthodians as a whole, including the earliest members of humans’ own deep evolutionary past, appear to cluster with ancient sharks.

“The common ancestors of all jawed vertebrates today organized their heads in a way that resembled sharks,” said Finarelli, PhD, Lecturer in Vertebrate Biology at University College Dublin. “Given what we now know about the interrelatedness of early fishes, these results tell us that while sharks retained these features, bony fishes moved away from such conditions.”

Furthermore, the analysis demonstrated that all of these early members of the modern gnathostomes are clearly separated from what now appear to be the most primitive vertebrates with jaws: a collection of armored fishes called placoderms.

“There appears to be a fundamental distinction between the placoderms and all other vertebrates with jaws,” Finarelli said.

This new revision of the lineage of early jawed vertebrates will allow paleontologists to dig into deeper mysteries, including how the body plan of these ancient species transformed over the transition from jawless to jawed fishes.

“It helps to answer the basic question of what’s primitive about a shark.” Coates said. “And, at last, we’re getting a better handle on primitive conditions for jawed vertebrates as a whole.”

“This study is an example of the power of phylogenetics combined with the comparative morphology of living and fossil organisms,” said Maureen Kearney, program director in National Science Foundation’s Division of Environmental Biology, which co-funded the research. “It shows us important evolutionary transitions in the history of life, providing a new window into the sequence of evolutionary changes during early vertebrate evolution.”

Smaller rainforests helped Carboniferous-Permian reptiles


Phylogeny of reptiles

From the BBC:

30 November 2010 Last updated at 09:12 GMT

Rainforest collapse kickstarted reptile evolution

By Paul Rincon Science reporter, BBC News

The fragmentation of tropical rainforests 300 million years ago helped pave the way for the rise of the dinosaurs, a new study suggests.

In the Carboniferous period, North America and Europe lay at the equator and were covered by steamy rainforest.

Global warming is thought to have brought about the collapse of these tropical habitats, triggering an evolutionary burst among reptiles.

The work, by a British team, is published in the journal Geology.

The forests that covered the ancient supercontinent of Euramerica are colloquially referred to as the Coal Forests.

They are so called because they accumulated a large amount of peat, which later turned into the coal that is mined today.

Towards the end of the Carboniferous, the Earth’s climate is thought to have grown hotter and drier.

“Climate change caused rainforests to fragment into small ‘islands’ of forest,” said co-author Howard Falcon-Lang, from Royal Holloway, University of London.

Dr Falcon-Lang continued: “This isolated populations of reptiles, and each community evolved in separate directions, leading to an increase in diversity.”

To reach their conclusions, the scientists studied the fossil record of reptiles before and after the collapse of the rainforests.

They showed that reptiles became more diverse and even changed their diets as they struggled to adapt to a rapidly changing climate and environment.

Advantage reptiles

Professor Mike Benton, from the University of Bristol, said: “This is a classic ecological response to habitat fragmentation.

“You see the same process happening today whenever a group of animals becomes isolated from its parent population.

“It’s been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands.”

His Bristol colleague Sarda Sahney commented: “It is fascinating that even in the face of devastating ecosystem-collapse, animals may continue to diversify.”

Amphibians appear to have been hardest hit by the collapse of the rainforests. The relative success of reptiles may have been due to physical adaptations in which they differed from amphibians.

Firstly, the hard-shelled eggs of reptiles could be laid on dry land (most amphibians lay theirs in water). Secondly, reptiles possess protective scales that help them retain moisture (amphibian skin is very permeable to water).

“These key adaptations freed them from the aquatic habitats to which amphibians were tied and gave them ecologic advantage in the widespread drylands that developed,” the researchers write in Geology.

See also here.

Only when tree-like plants with deep roots took hold some 330 million years ago did river banks finally come under control, say researchers: here.

Pompeii-like, a 300-million-year-old tropical forest was preserved in ash when a volcano erupted in what is today northern China. A new study by University of Pennsylvania paleobotanist Hermann Pfefferkorn and colleagues presents a reconstruction of this fossilized forest, lending insight into the ecology and climate of its time: here.

US housewife discovers fossil amphibian footprints


This video is called Geologic Time Carboniferous Permian.

From the Birmingham News in the USA:

Walker County woman finds ancient amphibian fossil

By Thomas Spencer — The Birmingham News

April 12, 2010, 6:15AM

Over Easter weekend, a Walker County housewife made a fossil find that would make a professional paleontologist envious: seven well preserved footprints made by a huge amphibian 300 million years ago in the muddy flats of prehistoric Alabama.

Cindy Wallace was on a field trip with her son, Gavin, to one of the world’s richest sites for Coal Age fossils, the former Union Chapel surface coal mine located near Sumiton in Walker County.

While Gavin scoured the rock piles for fossils, Wallace used a tiny watch screwdriver and a rock to chip at a piece of slate. When the layers broke apart, it revealed the hand-sized tracks of Attenosaurus subulensis, a wolf-sized salamander that was the largest terrestrial creature living during the period prior to the emergence of the dinosaurs.

“It has some of the best preserved tracks of the Attenosaurus that have been found,” said Carl Sloan, secretary of the Alabama Paleontological Society, which has been instrumental in the discovery, preservation and fossil collection at the Union Chapel Mine site.

Jun Ebersole, the collections manager of McWane Science Center, agreed.

“The tracks are some of the best ever found in the state,” he said.

At the time the Attenosaurus was prowling Walker County, the area was an alluvial plain of tropical forest and tidal flats on the coast of an ancient ocean. The remains of the lush tropical forests accumulated in thick blankets of peat which were then covered over and buried. Over time, under pressure and heat, the peat was transformed into the coal deposits the region is known for.

The Union Chapel Mine site was discovered in 1999 by a high school science teacher, Ashley Allen, who found a treasure trove of fossil impressions of plants and animals from the Coal Age in the area.

The mine was due to be covered over under the requirements of the Mining Reclamation Act until a coalition of amateur fossil hunters waged a campaign to have it preserved.

Currently owned by the state of Alabama, the site, now known as the Steven C. Minkin Paleozoic Footprint Site, has produced thousands of plant fossils and animal and insect tracks. The Paleontology Society manages access to the site, and visitors are allowed to keep fossils unless they are deemed to be significant enough to merit further study or inclusion in a museum collection. Wallace’s find is headed for the McWane Center collection.

Wallace had taken her 12-year-old son, Gavin, on the expedition with Fresh Air Family, an organization that leads parents and children on outdoor explorations around the state.

Gavin started collecting fossils at 5 and has amassed a collection of more than 600 fossils. Most have come from the wooded area near his family’s home in Empire, with others coming from his grandfather, a retired coal miner, who’d gathered fossils of starfish and ferns he’d found in the mines.

But for Cindy Wallace, the Attenosaurus tracks were her first find.

“It was my very first fossil,” Wallace said.

tspencer@bhamnews.com

“Mexican salamander helps uncover evolution, genetics of stem cells – Oneindia”: here.

Fossil and present giant salamanders: here.

Also amphibians had their glory period during the long history of life on our planet; this happened during the Permian Period (299-251 million years ago), when they thrived together with the Synapsids reptiles. This, before the great mass-extinction that exterminated about 90% of all living species. Eryops megacephalus (from the Greek “mega”=“large” and “cephalos”=“head”) was one of the most common amphibians of that period and it lived in the swampy areas of North America about 270 million years ago. It was named by Edward Drinker Cope (1840-1897) in 1887: here.

Some extinct amphibians developed very particular forms of their body to have better chance to survive. Diplocaulus, for example, had a wide boomerang-shaped head that maybe made difficult for predators to swallow it and/or was used as a rudder for swimming. This particular head has made Diplocaulus one of the most popular amphibians, not only among the specialists: here.

Amphibians were able to reach enormous dimensions and an appearance similar to that of the gigantic crocodiles of the Mesozoic when they didn‘t find enough competitors for food in their environment. Their “champion” was surely Prionosuchus that lived in the late Permian, about 270 million years ago in the southern area of the super-continent Pangaea corresponding to Brazil: here.

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