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Frog evolution linked to dinosaur asteroid strike

The huge diversity of frogs we see today is mainly a consequence of the asteroid strike that killed off the dinosaurs, a study suggests.
A new analysis shows that frog populations exploded after the extinction event 66 million years ago.
It would appear to contradict earlier evidence suggesting a much more ancient origin for many key frog groups.

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Ancient salamander in amber shocks scientists

There can be a lot of drama in a drop of amber. Scientists at Oregon State University imagine a desperate struggle that took place between a baby salamander and an unknown foe over 20 million years ago.
The salamander may have squeaked away minus a leg, but it couldn't escape the sticky resin that left it wonderfully intact for those scientists to discover many, many years later.

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'Monster salamanders' found in fossilised mass grave

Scientists have discovered a new species of massive, toothy amphibian dating from 220 million years ago.
Hundreds of the creatures probably died when a lake dried up, leaving a huge jumble of bones which is now being excavated in southern Portugal.
Although related to modern salamanders, the two-metre beast probably lived more like a crocodile, snapping up fish and scrapping with rivals on the shore.

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Ancient armoured amphibian had world's oddest bite
A peculiar amphibian that was clad in bony armour prowled warm lakes 210 million years ago, catching fish and other tasty snacks with one of the most unusual bites in the history of life on Earth.
The creature called Gerrothorax pulcherrimus, which lived alongside some of the early dinosaurs, opened its mouth not by dropping its lower jaw, as other vertebrate animals do.
Instead, it lifted back the top of its head in a way that looked a lot like lifting the lid of a toilet seat.

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Kryostega collinsoni
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When the world's land was congealed in one supercontinent 240 million years ago, Antarctica wasn't the forbiddingly icy place it is now. But paleontologists have found a previously unknown amphibious predator species that probably still made it less than hospitable.
The species, named Kryostega collinsoni, is a temnospondyl, a prehistoric amphibian distantly related to modern salamanders and frogs. K. collinsoni resembled a modern crocodile, and probably was about 15 feet in length with a long and wide skull even flatter than a crocodile's.
In addition to large upper and lower teeth at the edge of the mouth, temnospondyls often had tiny teeth on the roof of the palate. However, fossil evidence shows the teeth on the roof of the mouth of the newly found species were probably as large as those at the edge of the mouth.

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 Discovering a species origin at the possible end of its existence is bittersweet for an assistant professor at the University of Calgary.
Jason Anderson, who works in the faculty of veterinary medicine, studies amphibians and has uncovered the missing link between frogs and salamanders, but he's not exactly rejoicing the significant discovery.

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Gerobatrachus hottoni
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The discovery of a "frogamander," a 290 million-year-old fossil that links modern frogs and salamanders, may resolve a longstanding debate about amphibian ancestry, Canadian scientists said on Wednesday.
Modern amphibians -- frogs, salamanders and earthworm-like caecilians-- have been a bit slippery about divulging their evolutionary ancestry. Gaps in the fossil record showing the transformation of one form into another have led to a lot of scientific debate.
The fossil Gerobatrachus hottoni or elderly frog, described in the journal Nature, may help set the record straight.

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A rock that sat untouched in a Pennsylvania museum's fossil collection for years has rare full-body imprints of not just one but three ancient amphibians.
Researchers found the imprints in sandstone rocks taken from the Mauch Chunk Formation in eastern Pennsylvania decades ago and stored in the Reading Public Museum. The body impressions of the salamander-like creatures are estimated to be 330 million years old, or about 100 million years before the first dinosaurs appeared.


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Unprecedented fossilised body imprints of amphibians have been discovered in 330 million-year-old rocks from Pennsylvania. The imprints show the unmistakably webbed feet and bodies of three previously unknown, foot-long salamander-like critters that lived 100 million years before the first dinosaurs.

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Amphibian Body Impressions from the Mississippian Mauch Chunk Formation, Eastern Pennsylvania

An exceptional case of preservation of three body impressions of Mississippian temnospondyl amphibians provides direct evidence of body shape, texture of the integument and possible social behaviour in 330-million-year old amphibians. These impressions are from the Mississippian (Visean) Mauch Chunk Formation near Pottsville, Schuylkill County, eastern Pennsylvania, USA. The three body impressions are preserved on a reddish brown, fine-grained sandstone slab with a clay drape. On one side of the slab, two tetrapod body impressions preserve nearly complete head, body and limb outlines in convex hyporelief; on the other side of the slab a sinusoidal ridge represents a median body/tail drag associated with an incompletely-preserved body impression, also in convex hyporelief. The shovel-shaped head, robust limbs, relatively short trunk and smooth integument readily distinguish the Mauch Chunk impressions from  Hermundurichnus and Sauropleura, the only named body impressions of Palaeozoic tetrapods. The footprints of the Mauch Chunk body impressions can be assigned to the ichnogenus Batrachichnus, which indicates that they are of a temnospondyl. This adds to the sparse and earliest records of temnospondyls, which are of Visean age. The smooth integument of the impressions does not support the presence of ventral scales or armour in the earliest temnospondyls, but body proportions of the Mauch Chunk body impressions indicate a relatively terrestrial temnospondyl not matched by any taxon now known from fossil skeletal remains. Three closely-associated impressions on a single bedding plane suggest some sort of gregarious behaviour in Mississippian temnospondyls. The head-to-tail overlap of two of the impressions may indicate that internal fertilization and associated courtship behaviour evolved independently in one group of amphibians more than 300 million years ago.

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