Conquering The Land (Animals Leaving The Sea)

[ramonmercado]

Man-sized scorpion lived in Scotland

A scientist poring over 330-million-year-old tracks in a layer of sandstone in Scotland believes they were made by an extraordinary water scorpion that was as big as a man.

Above: A regular scorpion...

The huge six-legged creature was about 1.6 metres (64 inches) long and a metre (40 inches) wide, according to the study, published on Thursday in Nature, the weekly British science journal.

The trackway, measuring six metres (20 feet) long, was found on the overhang of a bed of sandstone that, 330 million years ago, was probably close to the sea and had the consistency of soft plaster.

The traces comprise crescent-shaped prints left by the creature's limbs and a sinuous curve believed to have been gouged out by its tail.

"The slow stilted progression, together with the dragging of the posterior, indicates that the animal was not buoyant and that it was probably moving out of the water," says Martin Whyte, a geography professor at Britain's University of Sheffield.

The find is unique, not just because of the gigantic size of the arthropod, but for the evidence it offers that this invertebrate species could survive out of water.

Until now, the only advanced creatures believed to have ventured onto land from the sea at that era were early tetrapods -- vertebrates with four limbs.

http://www.physorg.com/news8601.html

Edit to amend subject title.

 

[ramonmercado]

Five-Foot Giant Water Scorpion Once Roamed U.K. Shores

November 30, 2005
If you think scorpions are scary, try this on for size: a six-legged water scorpion the size of a human. Newly discovered tracks reveal that about 330 million years ago, just such a creature lumbered along the riverbanks in present-day Scotland.

The fossilized track is the largest of its kind ever found and shows these now extinct creatures could walk on land, according to Martin Whyte, a geologist at the University of Sheffield in England.


"There's been lot of debate about this particular [species of] water scorpion—whether it could only live in water or if it could come out. … What the track shows is they could come out at least for short intervals," he said.

The geologist describes the find in tomorrow's issue of the science journal Nature.

Blair Hedges, an evolutionary biologist at Pennsylvania State University in University Park, agreed that the tracks looks like they were made on solid ground.

"That tell us that about this time our ancestors, the first vertebrates with four limbs instead of fins, were confronting very large arthropods on land," he said. "That's the neat thing it brings up."

Slow Crawl

The footprints were made by a species of Hibbertopterus, a family of water scorpions that are among the largest arthropods—a group that includes insects and crustaceans—ever known.

Whyte estimates the individual who made the track was 5.2 feet (1.6 meters) long and 3.2 feet (1 meter) wide.

The track itself is 20 feet (6 meters) long and about 3 feet (1 meter) wide.

"It's huge, absolutely giant," Hedges said. "To consider an arthropod made the thing, that's really impressive. A lot of people don't realize the arthropods of that time period, including dragonflies, millipedes, and centipedes, were much larger than today."

Whyte's analysis of the tracks suggests that the ancient water scorpion took its sweet time as it lumbered along the shoreline.

He said the creature walked in-phase, with each pair of limbs moving forward at the same time rather than alternating, like a human gait. Also, the scorpion's stride averaged 10.6 inches (27 centimeters) long, short enough that they overlapped.

The track also features a central groove left by the water scorpion's dragging tail, leaving indications of jerky movements.


"The whole thing adds up to fairly look as though the body [was] heavy and the animal was moving quite slowly," Whyte said. "For that reason I think it was out of the water. Had it been in [the water], water would've buoyed up the tail."

Simon Braddy, an earth scientist at the University of Bristol in England, specializes in ancient water scorpion tracks. He said the evidence is "unclear" that these newly discovered tracks were made on land.

"Sometimes you find mud cracks on a surface that are a sure sign, but these are lacking in this case," he said in an e-mail interview.

Hedges, the Pennsylvania State University biologist, disagrees, saying the analysis "makes sense."

"I don't know for absolute certain, but it made a track, so it was walking on a mucky surface. Maybe it was right at the water's edge, which is where the first tetrapods would have occurred as well," he said.

Tetrapods are four-limbed creatures with backbones, a group that includes humans. The earliest ones looked like giant salamanders, measuring about four feet (1.2 meters) long, Hedges said.

Landward Ho

According to Hedges, by about 360 million years ago the transition of lobe-finned fish—prehistoric fish with fleshy fins—to four-limbed tetrapods was nearly complete.

The newly discovered trackway, which is dated to 330 million years ago, therefore suggests that some of the earliest tetrapods would have confronted these giant water scorpions as they scurried about the shore.

"All kinds of things are brought out by discoveries like these," Hedges said. "For example, what kind of interactions would have occurred between these giant water scorpions and the early tetrapods?"

According to Whyte, even though water scorpions shared the same environment with tetrapods, the six-legged giants likely left our ancestors alone.

"They didn't have large pincers or aggressive weaponry that would have made them a danger to the early tetrapods," he said. "If anything the tetrapods were more a danger to them than the reverse."

http://news.nationalgeographic.com/news/2005/11/1130_051130_giant_scorpion.html

 

[ramonmercado]

Ancient walking mystery deepens

By Helen Briggs
BBC News

Reconstruction of the body of Ichthyostega

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One of the first creatures to step on land could not have walked on four legs, 3D computer models show.

Textbook pictures of the 360-million-year-old animal moving like a salamander are incorrect, say scientists.

Instead, it would have hauled itself from the water using its front limbs as crutches, research in Nature suggests.

The move from living in water to life on land - a pivotal moment in evolution - must have been a gradual one.

Ichthyostega is something of an icon in the fossil world. Living during the Upper Devonian period, it was dubbed a "fishapod", with its mixture of fish-like and amphibious features.

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Our reconstruction demonstrates that the old idea, often seen in popular books and museum displays, of Ichthyostega looking and walking like a large salamander, with four sturdy legs, is incorrect”

Prof Jenny Clack
University of Cambridge

Although it probably spent much of its time under water, at times it was thought to have crawled halfway up onto land on limb-like flippers.

Exactly how it moved on land has been a matter of much debate, however.

Now, a team from The Royal Veterinary College, London and the University of Cambridge, has spent three years reconstructing the first 3D computer model of Ichthyostega from fossils.

It enabled them to study how ancient vertebrates made the "monumental transition" from swimming to walking.

Study author Dr Stephanie Pierce, of The Royal Veterinary College, said the 3D skeleton allowed them to calculate the range of movement in the joints of its limbs for the first time.

The research suggests the animal shuffled on land using hind limb movements similar to that seen in seals rather than moving its limbs in the familiar walking pattern seen today.

Dr Pierce told BBC News: "We're almost bringing the animal back to life by doing this.

"What we've discovered is that some early tetrapods definitely did not have the ability to walk on land. We at this stage are not actually sure which animals - or group of animals - were the first to do this."

Co-author Prof Jenny Clack from the University of Cambridge added: "Our reconstruction demonstrates that the old idea, often seen in popular books and museum displays, of Ichthyostega looking and walking like a large salamander, with four sturdy legs, is incorrect."

Fundamental question

Commenting on the study, Dr Susannah Maidment of London's Natural History Museum, said understanding where we came from, or where all the things that live on the land came from, is one of the most fundamental questions.

http://www.bbc.co.uk/news/science-environment-18177493

"What this study suggests is that this animal, which has been traditionally thought of as the first four legged animal to walk on land wasn't walking on land at all.

"It sends us almost back to the drawing board...I guess it even sends you back to the field to look for more fossils."

The research, reported in a paper in Nature, was funded by the Natural Environment Research Council.

 

[Comfortably Numb]

Fossil is the oldest-known scorpion

Researchers think it was one of the first animals to spend time on land

Source: Ohio State University / sciencedaily.com
Date: 16 January, 2020

Scientists studying fossils collected 35 years ago have identified them as the oldest-known scorpion species, a prehistoric animal from about 437 million years ago. The researchers found that the animal likely had the capacity to breathe in both ancient oceans and on land.

The discovery provides new information about how animals transitioned from living in the sea to living entirely on land: The scorpion's respiratory and circulatory systems are almost identical to those of our modern-day scorpions -- which spend their lives exclusively on land -- and operate similarly to those of a horseshoe crab, which lives mostly in the water, but which is capable of forays onto land for short periods of time.

The researchers named the new scorpion Parioscorpio venator. The genus name means "progenitor scorpion," and the species name means "hunter." They outlined their findings in a study published today in the journal Scientific Reports.

https://www.sciencedaily.com/releases/2020/01/200116121903.htm

 

[EnolaGaia]

Newly published research demonstrates that some of the aquatic species who hauled themselves onto land eventually returned to the sea.

Ancient homesick 'fishapod' abandoned the land and returned to the sea, fossils show

Long before the dinosaurs appeared, when the first forests stretched toward the sky and enormous insects ruled Earth, a humble, shovel-faced fish with particularly strong fins decided to try its luck on dry land. Around the same time, another early land-exploring fish decided terrestrial life was overrated and fled back into the ocean, scientists recently discovered.

The fish that chose to stay on land was Tiktaalik roseae — more commonly known as simply Tiktaalik, after an Inuktitut word meaning "large freshwater fish" — and it is considered to be one of the oldest common ancestors of all land-dwelling vertebrates, from dinosaurs to mammals.

With foot-like fins that helped it haul itself out of water and onto shallow riverbanks, Tiktaalik is sometimes called a "fishapod," or footed fish. And Tiktaalik wasn't alone on this evolutionary journey.

Other fishapods of the time were also evolving the ability to haul themselves onto land — only to turn right around and head back into the water.

In a study published July 20 in the journal Nature ... , researchers described the fossils of an ancient fishapod called Qikiqtania wakei, named for the Inuktitut word describing the region of the Canadian Arctic where both Tiktaalik and Qikiqtania were uncovered. Both species lived during the Late Devonian period, around 375 million years ago. ...

Qikiqtania seems to be a species in the midst of an evolutionary about-face. After evolving a body similar to that of Tiktaalik and the amphibious tetrapods (four-legged animals) that would follow it, Qikiqtania returned to the water and began evolving back into a full-fledged fish.

According to the study authors, this fossil's discovery fleshes out the messy story of vertebrate evolution in ways that Tiktaalik alone could not. ...

FULL STORY: https://www.livescience.com/tiktaalik-relative-qikiqtania

PUBLISHED RESEARCH REPORT: https://www.nature.com/articles/s41...2172&CJEVENT=296eaa03089d11ed800e00dd0a82b832