Sea cucumber fossil relative discovery


This is a 3D reconstruction of Sollasina cthulhu. Tube feet are shown in different colors. Credit: Imran Rahman, Oxford University Museum of Natural History

From the University of Oxford in England:

Cthulhu‘ fossil reconstruction reveals monstrous relative of modern sea cucumbers

New species of extinct sea cucumber named Sollasina cthulhu, for its resemblance to H.P. Lovecraft’s famous monster

An exceptionally-preserved fossil from Herefordshire in the UK has given new insights into the early evolution of sea cucumbers, the group that includes the sea pig and its relatives, according to a new article published today in the journal Proceedings of the Royal Society B.

Palaeontologists from the UK and USA created an accurate 3D computer reconstruction of the 430 million-year-old fossil which allowed them to identify it as a species new to science. They named the animal Sollasina cthulhu due to its resemblance to monsters from the fictional Cthulhu universe created by author H.P. Lovecraft.

Although the fossil is just 3 cm wide, its many long tentacles would have made it appear quite monstrous to other small sea creatures alive at the time. It is thought that these tentacles, or ‘tube feet’, were used to capture food and crawl over the seafloor.

Like other fossils from Herefordshire, Sollasina cthulhu was studied using a method that involved grinding it away, layer-by-layer, with a photograph taken at each stage. This produced hundreds of slice images, which were digitally reconstructed as a ‘virtual fossil’.

This 3D reconstruction allowed palaeontologists to visualise an internal ring, which they interpreted as part of the water vascular system — the system of fluid-filled canals used for feeding and movement in living sea cucumbers and their relatives.

Lead author, Dr Imran Rahman, Deputy Head of Research at Oxford University Museum of Natural History said:

“Sollasina belongs to an extinct group called the ophiocistioids, and this new material provides the first information on the group’s internal structures. This includes an inner ring-like form that has never been described in the group before. We interpret this as the first evidence of the soft parts of the water vascular system in ophiocistioids.”

The new fossil was incorporated into a computerized analysis of the evolutionary relationships of fossil sea cucumbers and sea urchins. The results showed that Sollasina and its relatives are most closely related to sea cucumbers, rather than sea urchins, shedding new light on the evolutionary history of the group.

Co-author Dr Jeffrey Thompson, Royal Society Newton International Fellow at University College London, said:

“We carried out a number of analyses to work out whether Sollasina was more closely related to sea cucumbers or sea urchins. To our surprise, the results suggest it was an ancient sea cucumber. This helps us understand the changes that occurred during the early evolution of the group, which ultimately gave rise to the slug-like forms we see today.”

The fossil was described by an international team of researchers from Oxford University Museum of Natural History, University of Southern California, Yale University, University of Leicester, and Imperial College London. It represents one of many important finds recovered from the Herefordshire fossil site in the UK, which is famous for preserving both the soft as well as the hard parts of fossils.

The fossil slices and 3D reconstruction are housed at Oxford University Museum of Natural History.

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Silurian marine life mass extinction, new research


This 2017 video is called The Evolution of Life part 4 : Silurian.

From Florida State University in the USA:

In ancient oceans that resembled our own, oxygen loss triggered mass extinction

March 28, 2019

Summary: Researchers provide first conclusive evidence linking widespread ocean oxygen loss and rising sea levels to a 430-million-year-old mass extinction event.

Roughly 430 million years ago, during the Earth’s Silurian Period, global oceans were experiencing changes that would seem eerily familiar today. Melting polar ice sheets meant sea levels were steadily rising, and ocean oxygen was falling fast around the world.

At around the same time, a global die-off known among scientists as the Ireviken extinction event devastated scores of ancient species. Eighty percent of conodonts, which resembled small eels, were wiped out, along with half of all trilobites, which scuttled along the seafloor like their distant, modern-day relative the horseshoe crab.

Now, for the first time, a Florida State University team of researchers has uncovered conclusive evidence linking the period’s sea level rise and ocean oxygen depletion to the widespread decimation of marine species. Their work highlights a dramatic story about the urgent threat posed by reduced oxygen conditions to the rich tapestry of ocean life.

The findings from their study were published in the journal Earth and Planetary Science Letters.

Although other researchers had produced reams of data on the Ireviken event, none had been able to definitively establish a link between the mass extinction and the chemical and climatic changes in the oceans.

“The connection between these changes in the carbon cycle and the marine extinction event had always been a mystery,” said lead author Seth Young, an assistant professor in FSU’s Department of Earth, Ocean and Atmospheric Science.

To address this old and obstinate question, Young and his co-authors deployed new and innovative strategies. They developed an advanced multiproxy experimental approach using stable carbon isotopes, stable sulfur isotopes and iodine geochemical signatures to produce detailed, first-of-their-kind measurements for local and global marine oxygen fluctuation during the Ireviken event.

“Those are three separate, independent geochemical proxies, but when you combine them together you have a very powerful data set to unravel phenomena from local to global scales,” Young said. “That’s the utility and uniqueness of combining these proxies.”

Young and his team applied their multiproxy approach to samples from two geologically important field sites in Nevada and Tennessee, both of which were submerged under ancient oceans during the time of the extinction event. After analyzing their samples at the FSU-based National High Magnetic Field Laboratory, the connections between changes in ocean oxygen levels and mass extinction of marine organisms became clear.

The experiments revealed significant global oxygen depletion contemporaneous with the Ireviken event. Compounded with the rising sea level, which brought deoxygenated waters into shallower and more habitable areas, the reduced oxygen conditions were more than enough to play a central role in the mass extinction. This was the first direct evidence of a credible link between expansive oxygen loss and the Ireviken extinction event.

But, Young found, that oxygen loss wasn’t universal. Only about 8 percent or less of the global oceans experienced significantly reducing conditions with very little to no oxygen and high levels of toxic sulfide, suggesting that these conditions didn’t need to advance to whole-ocean scale to have an outsized, destructive effect.

“Our study finds that you don’t necessarily need the entire ocean to be reducing to generate these kind of geochemical signatures and to provide a kill mechanism for this significant extinction event,” Young said.

Today, like 430 million years ago, sea level is on the rise and ocean oxygen is hemorrhaging at an alarming rate. As parallels continue to emerge between today’s changes and past calamities, peering into the Earth’s distant past could be a critical tool in preparing for the future.

“There are common threads with other climatic and extinction events throughout Earth’s history, and future work will continue to help us understand the similarities and differences of these events to constrain future climate predictions,” said co-author Jeremy Owens, an assistant professor in FSU’s Department of Earth, Ocean and Atmospheric Science who has worked on other extinction events in the Jurassic and Cretaceous periods.

“I think it’s important to see how these events played out all the way from extinction interval through recovery period, how severe they were and their connections to the ancient environment along the way,” added Young. “That could help us figure out what’s in store for our future and how we can potentially mitigate some of the negative outcomes.”

This study was funded by the National Science Foundation and the Geological Society of America.

Late in the prehistoric Silurian Period, around 420 million years ago, a devastating mass extinction event wiped 23 percent of all marine animals from the face of the planet. For years, scientists struggled to connect a mechanism to this mass extinction, one of the 10 most dramatic ever recorded in Earth’s history. Now, researchers from Florida State University have confirmed that this event, referred to by scientists as the Lau/Kozlowskii extinction, was triggered by an all-too-familiar culprit: rapid and widespread depletion of oxygen in the global oceans: here.

Silurian fossil worm discovery


This 30 January 2017 video says about itself:

500-million year-old species offers insights into the lives of ancient legged worms

A new species of lobopodian, a worm-like animal with soft legs from the Cambrian period (541 to 485 million years ago), has been described for the first time from fossils found in the Burgess Shale in the Canadian Rocky Mountains. Details of the new species, called Ovatiovermis cribratus, are being published in the open access journal BMC Evolutionary Biology this week.

Read more here.

From the University of Oxford in England:

New species of rare ancient ‘worm’ discovered in fossil hotspot

August 8, 2018

Scientists have discovered a new species of lobopodian, an ancient relative of modern-day velvet worms, in 430 million-years-old Silurian rocks in Herefordshire, UK.

The team, comprising researchers from the universities of Oxford, Yale, Leicester and Manchester, and Imperial College London, has been able to three-dimensionally reconstruct the exceptionally well-preserved fossil using digital technology.

The research is reported in the Royal Society journal Open Science.

First author Derek Siveter, Professor Emeritus of Earth Sciences at Oxford University and Honorary Research Associate at Oxford University Museum of Natural History, said: ‘Lobopodians are extremely rare in the fossil record, except in the Cambrian Period. Worm-like creatures with legs, they are an ancestral marine relative of modern-day velvet worms, or onychophorans — predators that live in vegetation, mainly in southern latitudes.

‘This new lobopodian, which we have named Thanahita distos, was discovered during fieldwork in an area of Silurian rocks in Herefordshire. It is the first lobopodian to be formally described from rocks of Silurian age worldwide; exceptionally, it is fully three-dimensionally preserved, and it represents one of only eight known three-dimensionally preserved lobopodian or onychophoran fossil specimens.

‘We have been able to digitally reconstruct the creature using a technique called physical-optical tomography. This involves taking images of the fossil at a fraction of a millimetre apart, then “stitching” together the images to form a “virtual fossil” that can be investigated on screen.’

Professor Siveter and colleagues have been carrying out fieldwork in Herefordshire since the mid-1990s. The sedimentary deposit in which it was discovered has since become known as the Herefordshire Lagerstätte, the term Lagerstätte indicating that it contains exceptionally preserved fossilised remains of soft-bodied animals. The fossils were deposited 430 million years ago within a marine basin that extended across what is now central England into Wales, and they are preserved in nodules in a soft, cream-colored volcanic ash mixed with marine sediment.

Professor Siveter said: ‘Thanahita distos and the other animals that became fossilised here likely lived 100 to 200 meters down, possibly below the depth to which much light penetrates. We deduce this because we found no vestiges of photosynthetic algae, which are common in contemporaneous rocks laid down at shallower points on the seafloor to the east.

‘Some special circumstances allowed for their remarkable preservation. The first was the immediate precipitation of clay minerals around the dead organisms, which decayed over time, leaving empty spaces behind. The mineral calcite — a form of calcium carbonate — then filled these natural moulds, replicating the shape of the animals. Almost at the same time, hard concretions began to form, being cemented by calcite. Thanks to the early hardening of these Silurian time capsules in this way, the fossils were not squashed as the ash layer slowly compacted.’

He added: ‘Some lobopodians lie in a position on the tree of life which foreshadows that of the terrestrial velvet worms, while others are precursors of the arthropods: the “king crabs”, spiders, crustaceans and related forms. Since its discovery, the Herefordshire Lagerstätte has yielded a diversity of arthropods that have contributed much to our understanding of the palaeobiology and early history of this very important invertebrate group. The lobopodian Thanahita distos belongs to an extended, panarthropod grouping.

‘Further, morphological analysis places it within a lobopodian group that typifies an earlier period of geological time in the Cambrian — about 520 to 510 million years ago — thus indicating the survival of this group over some 100 million years.’

How Silurian echinoderms ate


This October 2015 video from Utah State University in the USA is called What does the fossil record reveal about the evolution of Echinoderms?

By Laurel Hamers, 7:05pm, September 12, 2017:

Like sea stars, ancient echinoderms nibbled with tiny tube feet

Rare 430-million-year-old fossils preserve signs of these tentacle-like limbs

Sea stars and their relatives eat, breathe and scuttle around the seafloor with tiny tube feet. Now researchers have gotten their first-ever look at similar tentacle-like structures in an extinct group of these echinoderms.

It was suspected that the ancient marine invertebrates, called edrioasteroids, had tube feet. But a set of unusually well-preserved fossils from around 430 million years ago, described September 13 in Proceedings of the Royal Society B, provides proof.

Usually, when an echinoderm dies, “the tube feet are the first things that go,” says Colin Sumrall, a paleobiologist at the University of Tennessee, Knoxville who wasn’t part of the study. “The thing that’s so stunning is that they didn’t rot away.”

An abundance of soft-bodied creatures from the Silurian Period, which lasted from 443 to 416 million years ago, are preserved in a fossil bed in Herefordshire, England. The edrioasteroids found in this bed were probably buried alive by volcanic ash, entrapped before their soft tissues could break down, says study coauthor Derek Briggs, a paleontologist at Yale University. Decaying tissue then left a void that was filled in by minerals, which preserved the shape of the appendages.

Briggs and his collaborators slowly ground three fossils down, taking pictures layer-by-layer to build up a three-dimensional view. The specimens are a new genus and species, the analysis revealed. Unlike relatively flat sea stars and sand dollars, the species — dubbed Heropyrgus disterminus — had a conical body about 3 centimeters long. Its narrower end anchored in the seabed. The other end sported a set of five plates partially covering dozens of tube feet arranged in a pentagonal ring.

Today’s echinoderms use hydraulic pressure in a water vascular system to extend and retract their tube feet, which serve a variety of roles. The feet can help animals pull in tiny particles of food, filter water or gases, and even inch along the seafloor. Based on the placement of H. disterminus’s tube feet (and the fact that it’s stuck in one place), the animal probably used the appendages mostly for feeding and gas exchange, Briggs suggests. The fossils didn’t preserve the internal tubing that hooks up to the tube feet, but Briggs’ team thinks that it’s a series of canals arranged like spokes connected to a wheel hub.

Sumrall isn’t surprised that this edrioasteroid had tube feet. “It’s exactly what we would have expected,” he says. But all other preserved tube feet to date come from classes of echinoderms that still have living relatives today. Edrioasteroids are less closely related to modern echinoderms, so this find broadens the range of species that scientists know sported the structures.

H. disterminus does have a few surprises, though: Its tube feet are found in two sets, in an arrangement not seen in any other echinoderms. And while it has five-point symmetry in its fleshy top part (like most other echinoderms), that transitions to eight-point symmetry in its long, columnar body.

Sea stars sighted predators 79 million years ago: here.

Ancient sea scorpions’ tails, weapons?


EN GARDE! Ancient sea scorpions (one illustrated, attacking an archaic fish) may have used serrated, swordlike tails for swimming or as weaponry. Picture by NATHAN ROGERS

From Science News:

Sea scorpions slashed victims with swordlike tails

New fossil suggests the body part was used for fighting, swimming

By Helen Thompson

11:00am, May 30, 2017

Ancient sea scorpions were hacks.

Some of the marine creatures had a thin, serrated spine on the tip of their tail — and that tail was surprisingly flexible, based on a 430-million-year-old fossil found in Scotland. Slimonia acuminata may have had the range of motion to strike large predators and prey, researchers report online April 18 in American Naturalist.

Scientists had thought that the ancient animals largely used their tails for swimming, primarily flapping them up and down like today’s lobsters and shrimp do and, to a limited degree, side to side like a rudder. But the tail on the new, well-preserved fossil curls dramatically to the side — a flexibility not seen in other sea scorpion specimens.

That bendiness suggests a purpose beyond propulsion, say study authors W. Scott Persons, a paleontologist, and John Acorn, an entomologist, both at the University of Alberta in Canada. The tail could have twisted around horizontally to strike a victim or dispatch a foe with the pointy end, and the saw-edged weapon would have encountered little water resistance.

Sea scorpions may have even pinned down prey with their front limbs while delivering lethal blows with their tails. Because S. acuminata appears quite early in sea scorpion evolution, slicing and dicing may have been the norm early on for the ancient critters, the researchers write.

Sea scorpions stabbed and slashed their prey to bits: here.

Sea lily fossils discovery in World War I trenches


This 2015 video from the USA is called Everything About Crinoids

From Ohio State University in the USA:

Rock exposed in World War I trenches offers new fossil find

Sea lily ancestors spent youth hitchhiking around ancient oceans, discovery suggests

April 3, 2017

Summary: An unusual fossil find is giving scientists new ideas about how some of the earliest animals on Earth came to dominate the world’s oceans.

An international research team found 425-million-year-old fossilized remnants of juvenile crinoids, a distant ancestor of today’s sea lilies, encased in iron oxide and limestone in the Austrian Alps.

Researchers collected the rock from a formation on the border between Italy and Austria known as the Cardiola Formation, which was exposed in trenches dug during World War I.

Crinoids were abundant long ago, when they carpeted the sea floor. Most stalked crinoid fossils depict spindly, plantlike animals anchored to sea floor rocks, explained William Ausich, professor of earth sciences at The Ohio State University and co-author of the study in the open-access journal Geologica Acta.

Fossils of juvenile crinoids are rare, he said.

Rarer still is that these newly uncovered crinoids weren’t attached to rocks when they died. Whatever they were attached to during their young lives didn’t survive fossilization.

“The fossils indicate that they were either attached to objects floating in the water at the time, or attached to another bottom dweller that lacked preservable hard parts,” said Ausich said.

They might have clung to free-floating algae beds or swimming cephalopods, either of which could have carried them far away from where they formed as larvae.

Modern sea lilies reproduce by ejecting sperm and eggs into the water. Larvae grow into free-floating juvenile animals and eventually attach to the ocean bottom, where they grow to adulthood within 18 months.

At least, that’s what sea lilies do today. This fossil find suggests that their distant ancestors sometimes settled on objects that carried them far from home before they reached reproductive age.

“We now have important information about the behavior of these ancient organisms, and a clue as to why they had such a wide geographic distribution,” Ausich said.

With long, stem-like bodies topped with feathery fronds, crinoids resembled flowers, though the center of the “flower” was a mouth, and the “petals” were arms that captured plankton for food. At the other end of the creature was star-shaped organ called a holdfast, which gripped the seafloor.

While some of today’s sea lilies are able to detach their holdfasts from the seafloor and walk short distances on their arms, they don’t do it often. If their crinoid ancestors spent their entire adult lives similarly anchored to one spot, they couldn’t have spread worldwide without help.

Fossilized holdfasts are all that remain of the young crinoids uncovered in the Alps, and that’s not unusual, Ausich said.

“The hard part about studying the fossils that I study is that they need to be buried alive in order to be completely preserved,” he explained. “Crinoids and other echinoderms have a skeleton comprised of innumerable individual calcite plates held together by various connective soft tissues. These tissues begin to decompose within a day of an organism’s death.

“So, having only parts [of crinoids] rather than whole organisms is actually the norm — as frustrating as that may be.”

The sediment that eventually covered these young crinoids must have been rich in iron, because the holdfasts were preserved as minerals of iron oxide — and that detail is unusual, he added.

Today, the fossil holdfasts look like rusty star-shaped rings. The stars measure only 1 to 4 millimeters across, meaning they came from very young, post-larval juveniles.

The tiny fossils might have been hard to isolate from the surrounding rock, but researchers were able to take advantage of the presence of iron oxide to dissolve the limestone and pull the fossils from the resulting slurry with a magnet.

Researchers had actually collected rock samples from the Cardiola Formation long ago, Ausich said. The area contains abundant fossils, including ancient corals and trilobites. But only recently did anyone discover that these particular rock samples also contained the crinoid holdfasts.

Researchers are interested in crinoids not just because they’re part of Earth’s history, but because the various crinoid species were able to survive millions of years of climate changes to become the sea lilies we know today.

Ancient crustacean fossil named after David Attenborough


This 21 March 2017 video from England is called Cascolus ravitis, a 430 Million-Year-Old ‘Exceptionally Preserved’ Fossil.

From the University of Leicester in England:

430 million-year-old fossil named in honor of Sir David Attenborough

Ancient relative of the lobsters and crabs complete with soft-parts is new to science

March 22, 2017

Summary: A new 430 million-year-old fossil has been discovered by scientists, and has been named in honor of Sir David Attenborough. The discovery is a unique example of its kind in the fossil record, say the authors of a new report.

An international team of scientists led by the University of Leicester has discovered a new 430 million-year-old fossil and has named it in honour of Sir David Attenborough — who grew up on the University campus.

The fossil is described as ‘exceptionally well preserved in three-dimensions’ — complete with the soft-parts of the animal, such as legs, eyes and very delicate antennae. The fossil has been determined as an ancient crustacean new to science — a distant relative of the living lobsters, shrimps and crabs. There are about 40,000 crustacean species known today.

The find comes from volcanic ash deposits that accumulated in a marine setting in what is now Herefordshire in the Welsh Borderland.

Professor David Siveter of the Department of Geology at the University of Leicester made the discovery working alongside researchers from the Universities of Oxford, Imperial College London and Yale, USA.

Professor Siveter said: “Such a well-preserved fossil is exciting, and this particular one is a unique example of its kind in the fossil record, and so we can establish it as a new species of a new genus.”

“Even though it is relatively small, at just nine millimetres long, it preserves incredible detail including body parts that are normally not fossilized. It provides scientists with important, novel insights into the evolution of the body plan, the limbs and possible respiratory-circulatory physiology of a primitive member of one of the major groups of Crustacea.”

The fossil is named Cascolus ravitis in honour of Sir David, who grew up on University College Leicester campus (the forerunner of the University), in celebration of his 90th birthday. Cascolus is derived from castrum meaning ‘stronghold’ and colus, ‘dwelling in’, alluding to the Old English source for the surname Attenborough; while ‘ravitis” is a combination of Ratae — the Roman name for Leicester — ‘vita’, life, and ‘commeatis’, a messenger.

Professor Siveter said: “In my youth, David Attenborough‘s early programmes on the BBC, such as ‘Zoo Quest‘, greatly encouraged my interest in Natural History and it is a pleasure to honour him in this way.”

Sir David Attenborough said: “The biggest compliment that a biologist or palaeontologist can pay to another one is to name a fossil in his honour and I take this as a very great compliment. I was once a scientist so I’m very honoured and flattered that the Professor should say such nice things about me now.”

Professor Siveter added: “The animal lived in the Silurian period of geological time. Some 430 million years ago much of southern Britain was positioned in warm southerly subtropical latitudes, quite close to a large ancient continent of what we now call North America, and was covered by a shallow sea. The crustacean and other animals living there died and were preserved when a fine volcanic ash rained down upon them.”

The fossil specimen has been reconstructed as a virtual fossil by 3D computer modeling.

New frog from the Peruvian Andes is the first amphibian named after Sir David Attenborough: here.