Ancient big sea scorpion discovery in Iowa, USA


Pentecopterus decorahensis. Image: Patrick Lynch/Yale University

From Vice.com in the USA:

This Prehistoric Sea Scorpion Was the Size of a Person

Written by Becky Ferreira

1 September 2015 // 01:00 AM CET

The fossilized remains of an enormous sea scorpion have been found in a Iowan fossil bed at the bottom of an ancient impact crater. (Take a moment to let all that sink in.)

Named for a Greek warship called the penteconter, Pentecopterus decorahensis is like some kind of evolutionary fever dream. The newly-discovered species was decked out with lethal clawlike appendages and an idiosyncratic, paddle-shaped leg that was likely used for locomotion.

Measuring almost six feet long, Pentecopterus was a veritable giant in the seas of the Ordovician period, some 467 million years ago.

“It was probably the largest animal in its ecosystem,” paleontologist James Lamsdell told me. Lamsdell is the lead author of a paper describing the animal, published today in the journal BMC Evolutionary Biology.

“From what we know, there was nothing else around that would have been likely to consider Pentecopterus prey,” he added. “It seems that Pentecopterus was the dominant animal in its ecosystem.”

This is even more impressive considering this species is the oldest eurypterid—the scientific term for sea scorpion—ever found in the fossil record. Eurypterids were a very diverse group of creatures that flourished for over 200 million years, before dying off at the dawn of the Triassic period. Among their ranks were the largest arthropods that ever roamed the Earth, and their close relatives live on today in the arachnid family.

The discovery of Pentecopterus pushes the evolutionary timeline of these influential animals back about nine million years, though Lamsdell said the eurypterid family tree’s roots run even deeper.

“We know that Pentecopterus is actually a relatively advanced eurypterid,” he told me. “The exciting thing about this is that it means that there must have been a number of other eurypterid groups around at the time too that we have yet to discover.”

“It is clear however that Pentecopterus was one of the earliest large predators in these complex ecosystems,” he added.

What’s more, Pentecopterus left behind the kind of beautifully fossilized remains that most paleontologists only dream about. “It is very rare to find such exquisite preservation in fossils of this age,” Lamsdell said. “I have never seen anything like this before in a eurypterid.”

The fine state of the specimens is due to the unique nature of Iowa’s Decorah crater where the fossils, which include both adult and juvenile members of the species, were excavated.

The crater was formed about 470 million years ago, when a 200-meter-wide meteorite impacted the Earth. The Ordovician oceans flooded the deformation, creating a shallow marine environment of brackish water. Here, Pentecopterus communities flourished, and when individuals died, they were etched into geological history by the crater’s deoxygenated seafloor, which provided perfect conditions for fossilization.

Indeed, according to Lamsdell, some of the fossils have even retained the creature’s hair and skin patterns. “The really exciting thing is that fine details like hair patterns can tell us a lot about the animals’ ecology,” he said.

“For animals with an external exoskeleton, hairs are the primary way in which they sense the world around them, as eyes can only be looking at one place at any one time,” he continued. “From looking at hair patterns we can see which parts of the animal were particularly sensitive.”

“For example, there are many hairs on the margins of the swimming paddle, meaning that it would have been very sensitive to changes in current flow, which would have helped it as a swimmer,” Lamsdell said.

So, to sum up: Paleontologists have inferred intimate details about a monster species of sea scorpion, the oldest yet found, which lived in the cozy fallout of a planetary collision nearly half a billion years ago. If that doesn’t rate high on your wow meter, you need to get it fixed.

See also here. And here. And here.

Ordovician echinoderm fossil from Utah, USA


This video is called Life Science – Echinoderms.

From Fossil Roulette:

30 January 2015

Name: Haimacystis rozhnovi
Location: Utah, USA, Wah Wah Limestone
Age: 466-488 million years ago, Ordovician Period

The early history of major groups of animals is often messy and mysterious. The suite of features that make those groups distinctive today show up piecemeal in different combinations in early species, like Haimacystis.

A long, thin column of discs and a flattened pod with a few wispy arms make up the body of this individual of Haimacystis. The animal is part of the same group that includes living sea stars, sea cucumbers, and intricately crowned sea lilies. The group also includes little-known, extinct animals like rhombiferans and corkscrew-armed gogiids.

Sea stars, sea lilies and other living animals in that group all have skeletons of calcified plates. All have five-part bodies that are usually symmetric.

Individuals of Haimacystis share some features with living members of their group, but their other features blur the neat distinctions that make five-part animals so different from other groups. They have calcified plates but they also have nineteen arms instead of five or ten. At best, they have two-part symmetry.

Haimacystis wasn’t a forerunner of its living relations or a species “on the way” to a more recognizable animals like starfish. Multiple species of sea lilies, one species of animals distantly related to sea stars, and at least six species of other early, irregular, extinct animals lived alongside Haimacystis. Haimacystis is its own subplot in the story of five-part animals.

Specimen Number: 1810TX5

References:

Sumrall, Colin D., James Sprinkle, and Thomas E. Guensburg. “Comparison of flattened blastozoan echinoderms: Insights from the early Ordovician eocrinoid Haimacystis rozhnovi.” Journal of Paleontology 75(2001):985-992.

Where are similar fossils found?

Bonus: The fossil’s name has an interesting backstory. “Haimacystis is a compound of the Greek haima, flowing blood, and cystis, sac, referring to the blood dripping from superficial leg wounds suffered by one of the co-authors when the biggest slab of specimens described herein toppled over and almost crushed him.” – Sumrall et al. 2001, p. 992

Prehistoric meteor shower and evolution of life discovery


This video is called Late Ordovician Mass Extinction (Ordovician – Silurian).

From daily The Independent in Britain:

Scientists discover fragment of ‘missing link’ asteroid that led to explosion of life on Earth

James Vincent

Thursday 03 July 2014

Scientists in Sweden have discovered a never-before seen class of meteorite that could be the ‘missing link’ between a gigantic collision in the asteroid belt 470 million years ago and the subsequent explosion of diverse life forms here on Earth.

Although it’s usually thought that meteorite impacts are disastrous for species on Earth (the classic example is the colossal impact thought to have killed off the dinosaurs 66 million years ago) there’s plenty of evidence to suggest that these events can also be beneficial to the overall diversity on the planet.

It’s thought that just such an impact – or rather, a string of them – dramatically boosted biodiversity on the planet during the Ordovician Period some 470 million years ago. It’s believed that a collision of two asteroids (or possibly an asteroid and a comet) out in space caused a shower of meteors to rain down on Earth.

Over time fragments of this meteor shower have been found around the planet and dated to 470 million years ago – but until now scientists had not found any evidence of the ‘killer’ asteroid that started this chain of events.

During the Ordovician Period most life on Earth was found in the ocean, with jawless fish, molluscs and insect-like arthropods making up the bulk of the species roll-call. However, a study from 2008 showed that the planet went through a “major phase of biodiversification” at this time shortly after “the largest documented asteroid breakup event during the past few billion years”.

The evidence for this breakup comes from the abundance of L-chondrite meteorites – the second most common meteorite type – fragments of which first started appearing on Earth around 470 million years ago.

“Something we didn’t really know about before was flying around and crashed into the L-chondrites,” said Gary Huss, co-author of the study that analysed the sample (published in Earth and Planetary Science Letters). This newly-discovered fragment is thought to be that very object – the mysterious ‘bullet’.

The composition of the fragment differs from known meteorite samples and its exposure age – the length of time it sailed through space – places it at the ‘scene of the crime’ when meteors rained down on the planet during the Ordovician Period.

“It’s a very, very strange and unusual find,” Birger Schmitz, the lead author of the study, told Live Science. “I think [it] adds to the understanding that the meteorites that come down on Earth today may not be entirely representative of what is out there.”

It’s not clear exactly why the Ordovician meteor shower led to a greater variety of life on the plane although some more far-fetched theories suggest that life itself was ‘seeded’ by organisms hitching a ride on asteroids.

A more likely explanation is that the impact craters caused by the collisions provided perfect test-beds for developing life. When meteorites hit the surface of the planet they scooped out bubbling pools of minerals and nutrients that served – in Carl Zimmer’s words – as “natural beakers that synthesized new chemicals essential for life”. However, even this is still just a theory – and the impacts might have also fostered life by creating new habitats, like restructured shorelines.

If further geochemical tests on the newly discovered fragment confirm its suspected origins then scientists will have pinned down another piece of the solar system’s history – but figuring out what happened closer to home might be more difficult still.

440 million years old fossil on Dutch beach?


The Texel fossil, photo by Bram Fey

A week ago, Hannes and Klaas Fey were walking on the beach near the Slufter nature reserve on Texel island, the Netherlands. Then, they found a small fossil.

Arthur Oosterbaan of Ecomare museum thinks the fossil may be a Hindia fibrosa. A sponge from the Ordovician, about 440 million years old.

Maybe about 150,000 years ago, during the Ice Age, a glacier transported the little sponge fossil from Scandinavia to Texel.

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Trilobite fossils of Kangaroo Island, Australia


This video is called Kangaroo Island / Australia.

From the Australian Broadcasting Corporation:

Narration: Kangaroo Island, South Australia. A holiday destination renowned for its beaches and natural splendours.

And soon to be renowned for some of the weirdest relics of ancient marine life in the world. …

Narration: Here in Emu Bay on the island’s north coast an international team of palaeontologists hosted by the South Australian Museum are digging up fossils from the Cambrian Period. They’re around 520 million years old, a time when life had only just begun to diversify.

These animals were living on the floor of an ancient sea. Many of them were arthropods, the group that includes modern crabs, lobsters, spiders, centipedes and insects. And by far the most common type of fossil is this one – a trilobite.

Jim: This is the largest species of trilobite. They’re called trilobites because they’ve got three lobes to them. And you see those ridges? They’re the eye ridges. So this thing could see.

Narration: Diego Garcia– from the University of Madrid – has seen fossils like this before – in the Burgess Shales of western Canada.

Talking about Diego Garcia and islands: it is to be hoped that this scientist Diego Garcia will fare better than the inhabitants of Diego Garcia island in the Indian ocean, driven off their island in order to make space for a US military base, now also a torture prison.

Tiny Trilobites Drifted in Cambrian Currents: here.

Signs of violence on agnostid trilobites found in Cambrian rocks suggest they were attacking each other: here.

Fossils record reveals ancient migrations, trilobite mass matings: here.

A new species of the Lower Ordovician pliomerid trilobite Pseudocybele: here.

It’s easy to travel responsibly on Kangaroo Island, where conservation is key to the wildlife that abounds: here.

July 2011: Nearly 700 people have planted 120,000 seedlings to help restore and protect the habitat on Kangaroo Island, Australia. The annual Kangaroo Island Planting Festival attracted 676 volunteers this year – almost 200 more than last year – with more than 100 different species planted to establish new habitat in the lower Cygnet Valley: here.