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Post Info TOPIC: Ancient Fish


L

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Neoceratodus forsteri
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Visual pigments in a living fossil, the Australian lungfish Neoceratodus forsteri
When prehistoric fish made their first forays onto land, what did they see? According to a study published in BMC Evolutionary Biology, it's likely that creatures venturing out of the depths viewed their new environment in full colour.
A team led by Helena Bailes at the School of Biomedical Sciences, University of Queensland, Brisbane, Australia, analysed retinas from Australian lungfish (Neoceratodus forsteri), thought to be the closest living relative to the first terrestrial vertebrates. The researchers then compared these to other fish and amphibian retinas. The DNA of five visual pigment (opsin) genes in the retinas of lungfish reveals that these have more in common with four-legged vertebrates (tetrapods) than with fish retinas.

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Tycheroichthys dunveganensis
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They went drilling for oil in northern Alberta and instead dug up a one-of-a-kind, 96-million year-old fossilized fish small enough to fit in your palm, but big enough to yield clues on how sea critters migrated in the age of Tyrannosaurus rex.
But to fish palaeontologist Alison Murray, the Tycheroichthys dunvenganensis is also a big question mark.

"It's complete fossil, which means it must have been killed and buried very, very quickly," said Murray, who now researches at the University of Alberta. It wasn't scavenged or broken apart in wave action. It must have been some sort of sudden event that killed it and trapped it in mud."

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Searching for a different kind of riches in the ground, an oil company made a priceless find it never expected.
Working in west-central Alberta, the now defunct Cequel Energy Inc. company thrust a 7.5-centimetre-wide drill more than 1,300 metres into the ground. When the tube pulled up a sample of earth, it revealed a 96-million-year-old fish fossil neatly encircled in the core sample - only the very tip of the fish's snout and tail were cut off by the drill.

"It was incredibly lucky. Sometimes in a core sample you'll find a bone or parts of a bone, but I can't ever remember finding a whole, intact fossil. It's really quite amazing" - Alison Murray, a palaeontologist at the University of Alberta.

Not only were the circumstances of the discovery amazing, Murray added, but the fossil represents a new genus of fish. Found just south of Grande Prairie, in an area known as the Dunvegan Formation, Tycheroichthys dunveganensis (meaning lucky fish of the Dunvegan) belongs to an extinct group of fishes, the Paraclupeidae, which are related to the modern-day herrings. It is the first time this group, which is known to have existed in areas around Lebanon and Brazil, has been found in Canada.

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RE: Ancient Fish
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When we lose our milk teeth they are replaced by new permanent teeth growing out in exactly the same positions. This is an ancient part of our evolutionary heritage and an identifying characteristic of the largest living group of backboned animals. Now, an international team including two scientists from Uppsala University has uncovered ancient fossil fish jaws that cast light on the origin of this group and its unique dentition. Together with scientists from Spain, Germany and France, Professor Per Ahlberg and Assistant Professor Henning Blom at the Department of Physiology and Developmental Biology have been studying two of the earliest bony fishes found in Sweden and Germany, managing to show that they belong to the same group of vertebrates as ourselves, the Osteichthyes.

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An extremely rare "living fossil" caught by a fisherman in Indonesia is being examined by scientists.

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Scientists are examining the Indonesian catch
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A 400 million-year-old fossil of a coelacanth fin, the first finding of its kind, fills a shrinking evolutionary gap between fins and limbs. The fossil shows that the ancestral pattern of lobed fins closely resembles the pattern in the fins of primitive living ray-finned fishes, according to the scientists.

"This ends intense debate about the primitive pattern for lobed fins, which involves the ancestry of all limbs, including our own" - Michael Coates, Ph.D., associate professor of organismal biology and anatomy at Chicago.

The fossil fin comes from a coelacanth, a type of lobe-finned fish, and provides the only skeletal fin remains to date from the extinct relatives of today's living coelacanths. Scientists spotted the 10 centimetre-long specimen at Beartooth Butte in northern Wyoming and have dubbed the fish Shoshinia arctopteryx after the Shoshine people and the Shoshone National Forest. When alive, the fish would have been about 46 to 62 centimetres in length.
The finding, detailed in the July/August issue of the journal Evolution & Development, shows the arrangement of bones within the fossil fin match the fin patterns found in primitive, living ray-finned fishes, such as sturgeons, paddlefishes and sharks.
Surprisingly, however, the patterns don't match the lobe-finned fish's living relative. Until now, scientists had assumed the living coelacanths and their relatives, the lungfish, served as accurate models of their ancestors dating back hundreds of millions of years ago.

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Coelacanth fish
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A surprised fisherman has caught only the second coelacanth known from Asia since it was first discovered here in 1998.
That fisherman, Justinus Lahama, found he had caught a fish so exceptional that an international team of scientists came to investigate.
French experts equipped with sonar and GPS this week asked Lahama to reconstruct, in his dugout canoe, exactly what it was he did that enabled him to catch the coelacanth fish, an awkward-swimming species that is among the world's oldest.

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Coelacanth
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A strange-looking creature that fishermen caught off the island of Zanzibar has been identified as a coelacanth, an ancient fish whose ancestors first swam in the planet's oceans more than 360 million years ago.
The fish, which weighs 27 kg and is 1.34 meters long, was caught off the tropical island's northern tip, according to researcher Nariman Jidawi of Zanzibar's Institute of Marine Science.
The coelacanth, a "living fossil" once thought to have gone extinct with the dinosaurs 65 million years ago, until one was caught off South Africa in 1938.

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Oldest vertebrate tissue
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Australian scientists say they have found morsels of fossilised muscle—the oldest vertebrate tissue ever known—in the remains of two fish that lived 380 to 384 million years ago.
Unearthed in western Australia 20 years ago, the specimens belong to two species of an extinct group of primitive, armoured fish known as placoderms.
The fish's remarkably well-preserved soft tissues include bundles of muscle cells, blood vessels, and nerve cells. They were found during recent electron microscope scans, the research team reported last week in the British journal Biology Letters.

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Walking Fish
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From 120m in the North Sea. A frogfish maybe from the genus Antennarius

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