Fossils

Biology

Ecology and Evolutionary Biology

U of T Mississauga

It all started with a grand claim: scientists had discovered the first known four-legged snake fossil from Brazil. The specimen, named Tetrapodophis amplectus, was small – about the size of a pencil – with tiny limbs. It was considered a significant discovery that offered paleontologists a major clue into the transition from limbed lizards to limbless snakes.

But the interpretation of this latest discovery didn’t sit well with �ؿ�ζSM’s Robert Reisz, a professor of biology at U of T Mississauga, and his colleagues – so he and Michael Caldwell, a professor of biological sciences at the University of Alberta, went to study the fossil in person.

“We came up with a much more plausible alternative explanation that this is not a snake, but a little lizard,” Reisz says.

Reisz adds the way in which the fossil was first obtained raised red flags. Around the mid-20th century, Brazil had outlawed fossil exports – but this artifact was illegally exported and bought by a private collector.

“It was quite unethical,” he says. “There are laws in place now to protect (these national treasures) and we should respect those and work within the system rather than be tempted by the attraction of an exciting fossil you get through unethical means.”

Fossil of Tetrapodophis amplectus (photo supplied by Robert Reisz)

Reisz and Caldwell went to Germany to look over the fossil, which was housed in a small, private museum that exhibits materials from the region, including Jurassic reptiles and dinosaurs.

“We re-studied it, spent a couple days with it, and found that the available evidence was much better than was originally presented ... because in addition to the actual fossil, there was also extensive impression,” Reisz says, adding that he and Caldwell got a lot of information from the impression of the specimen’s skull.

He explains that when a fossil forms between layers of rock, the impression it creates as it becomes rock, together with sediments, is extremely valuable because of its precision.

In this case, the rock that the fossil was extracted from was split – with the skeleton and skull on opposite sides of the slab. The shape of each was preserved as an impression on the opposite side. The original study overlooked the natural impression that showed that the skull was “more lizard-like than snake-like,” Reisz says.

Reisz says snakes have an extremely mobile skull where many bones are reduced and others are loosely connected to each other – particularly around the back end of the skull and jaw joint. He adds that snakes can also move several bones out of the way, while still connected to each other in the skull, to swallow prey whole.

Reisz and Caldwell also discovered that the original authors’ claims about the arrangement of the specimen’s teeth were false.

He explains that a snake’s teeth are designed to allow prey to go in one direction down the mouth, but they are strongly curved to prevent any movement out of the mouth. “So not only was the skull more lizard-like than snake-like, but the teeth were more lizard-like too,” Reisz says.

While he and his colleagues found that the Tetrapodophis amplectus wasn’t a snake, Reisz says it’s still a significant fossil. The team found that the anatomy was consistent with the anatomy of dolichosaurs – an group of extinct marine lizards from the Cretaceous period. It shows yet another example of the way lizards evolved and reduced their limbs to adapt to their environment, he says.

Reisz adds that the story also serves as a reminder that “science is a quest for truth, and the closer we get to the truth, the better.”

“We want to find out, and get as close to, the truth as possible,” he says. “Every time we find yet another interesting fossil, it gets us closer to that. We find out more about life before us.”

Prehistoric marine worm caught prey with spines deployed from head: U of T and Yale University research

ullahnor — Thu, 03 Aug 2017 16:18:25 +0000

Prehistoric marine worm caught prey with spines deployed from head: U of T and Yale University research

ullahnor Thu, 08/03/2017 - 12:18

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The “Capinatator praetermissus,” a primitive arrow worm, was identified from 508-million-year-old Burgess Shale fossils. Today these predatory marine worms are smaller and found in plankton (illustration by Marianne Collins/ROM)

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Global Lens

Palaeontology

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“Capinatator” is a new species of arrow worm from the Cambrian period

A team of scientists has identified a small marine predator that once patrolled the ocean floor and grabbed its prey with 50 spines deployed from its head.

Named Capinatator praetermissus, this ancient creature is roughly 10 centimetres long and represents a new species within the group of animals known as chaetognaths – small, swimming marine carnivores also known as arrow worms.

At more than 500 million-years-old, Capinatator is thought to be a forerunner of the smaller chaetognaths that are abundant in today’s oceans, where they make up a large portion of the world’s plankton and the ocean food chain. It is one of the largest chaetognaths known, according to a paper published today in Current Biology.

“This new species would have been an efficient predator and a terrifying sight to many of the smallest marine creatures that lived during that time,” said Jean-Bernard Caron, an associate professor in the departments of ecology & evolutionary biology and earth sciences at U of T's Faculty of Arts & Science.

He is also a senior curator of invertebrate palaeontology at the Royal Ontario Museum (ROM). Caron made the identification with Derek Briggs of Yale University, based on 50 specimens from the fossil-rich Burgess Shale in British Columbia.

“This is the most significant fossil discovery about the chaetognath group of animals to date,” said Briggs, a professor of geology and geophysics and a curator at the Yale Peabody Museum of Natural History.

Of the specimens studied, many preserve the feeding apparatus attached to the head, with some showing evidence of the rest of the body. Forty-eight specimens are held by the ROM. This one is from the Collins Quarry at Mount Stephen in the Yoho National Park, B.C. (photo by Jean-Bernard Caron)

According to the researchers, Capinatator’s head configuration is unique. With about 25 spines in each side of its head, the species has nearly double the maximum number of spines found in today’s chaetognaths. This enabled Capinatator to capture prey by closing the two halves of its grasping spines toward each other as it swam.

Briggs and Caron also determined that while it is fairly common to find evidence of chaetognath spines, fossilized chaetognath bodies are extraordinarily rare. Many of the Capinatator specimens in this study included evidence of soft tissues.

“These Burgess Shale fossil specimens preserve evidence of features such as the gut and muscles, which normally decay away, as well as the more decay-resistant grasping spines,” said Briggs. “They show that chaetognath predators evolved during the explosion of marine diversity during the Cambrian period and were an important component of some of the earliest marine ecosystems.”

The species name praetermissus means “overlooked.” The name Capinatator is derived from capio, which means “to grasp” and natator, which means “swimmer.”

The material for this study, currently held in the ROM’s collections, was collected under research and collecting permits provided by Parks Canada. The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks. Parks Canada protects the sites and works with leading scientific researchers to expand knowledge and understanding of this key period of earth history. The Burgess Shale was designated a UNESCO World Heritage Site in 1980.

Research funding was provided by the NASA Astrobiology Institute, the Natural Sciences and Engineering Research Council, the ROM Reproductions Fund and the Louise Hawley Stone Charitable Trust Publications Fund.

Read other species identified from the Burgess Shale

Ouch! U of T paleontologists identify 508-million-year-old sea creature with can opener-like pincers

ullahnor — Wed, 26 Apr 2017 15:39:11 +0000

Ouch! U of T paleontologists identify 508-million-year-old sea creature with can opener-like pincers

ullahnor Wed, 04/26/2017 - 11:39

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Reconstruction of “Tokummia katalepsis” showing a pair of large pincers at the front for capturing prey with much of the multi-segmented body protected by a hardened shell (illustration by Lars Fields)

Sean Bettam

Author legacy

Sean Bettam

Topic

Marine

Ecology & Evolutionary Biology

Paleontology

Earth Sciences

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Discovery points to origin of millipedes, crabs and insects among other species

Paleontologists at the �ؿ�ζSM and the Royal Ontario Museum (ROM) have uncovered a new fossil species that sheds light on the origin of mandibulates, the most abundant and diverse group of organisms on Earth, to which belong familiar animals such as flies, ants, crayfish and centipedes.

The finding was announced in a study published today in Nature.

U of T researchers and science illustrator bring fossilized creatures to life

geoff.vendeville — Mon, 27 Feb 2017 16:06:28 +0000

U of T researchers and science illustrator bring fossilized creatures to life

geoff.vendeville Mon, 02/27/2017 - 11:06

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A scientific illustration of Ovatiovermis cribratus shows how this legged worm-like creature would have looked like with its front-feeding limbs extended (illustration by Danielle Dufault ©Royal Ontario Museum)

Geoffrey Vendeville

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Geoffrey Vendeville

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U of T researchers – some of whom are students – have uncovered fossils of creatures that roamed the earth or swam in its waters millions of years ago.

But it’s only with the help of science illustrators like Danielle Dufault at the Royal Ontario Museum that they are able to bring these long-extinct species back to life.

After many hours of research and consultation with experts, she depicts ancient creatures using traditional and digital media.

“Being able to work and collaborate with scientists gives you the opportunity to learn every day,” she told U of T News. “This is honestly my dream job.”

On Tuesday, Dufault will be speaking at the annual ROM Research Colloquium and Vaughan Lecture, about her work with researchers.

Read about Moysiuk in The New York Times

Moysiuk said the process can help researchers refine their hypotheses.

“If something doesn’t make sense in the reconstruction, you have a chance to go back and look at the fossils to see why,” he said.

“For our project, it was particularly difficult to determine how the helens (curving spines) would have been positioned relative to the body in the living hyolith.”

U of T Associate Professor Jean-Bernard Caron and researcher Cédric Aria, who recently completed a PhD in U of T's department of ecology and evolutionary biology, have worked with Dufault to illustrate a new species, Ovatiovermis cribratus, a 500-million-year-old worm-like creature said to be no longer than a thumb.

Aria said he had also worked with Dufault to animate a fossil called Yawunik, a lobster-like, Cambrian-age predator which is an ancestor of butterflies and spiders.

The pictures, which end up in studies, textbooks and museums, help communicate research findings to a wide audience, Aria said. In fact, the depictions are partly what drew him to the field.

“If I am a paleontologist today, it is because some reconstructions of prehistoric animals have managed to capture both the novelty and the reality of extinct life,” he said.

500-million-year-old species – detailed by U of T scientists – offers insight into ancient legged worms

ullahnor — Tue, 31 Jan 2017 15:24:35 +0000

500-million-year-old species – detailed by U of T scientists – offers insight into ancient legged worms

ullahnor Tue, 01/31/2017 - 10:24

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A scientific illustration of Ovatiovermis cribratus shows how this soft-bodied marine animal would have looked like with its front-feeding limbs extended (illustration by Danielle Dufault ©Royal Ontario Museum)

Royal Ontario Museum

Author legacy

Royal Ontario Museum, Faculty of Arts & Science

Topic

Ecology and Evolutionary Biology

ROM

Earth Sciences

New Species

A new species of lobopodian – a worm-like animal that could stand nearly upright – from the Cambrian period (541 to 485 million years ago), has been detailed for the first time from fossils found in the Burgess Shale in the Canadian Rocky Mountains.

Details of the new species, called Ovatiovermis cribratus, have been published in the open access journal BMC Evolutionary Biology.

The new species is only the third lobopodian that has been formally described from the Burgess Shale. It is one of the rarest species found there, and now it's in the collections of the Royal Ontario Museum in Toronto.

Jean-Bernard Caron, an associate professor at U of T and senior curator of invertebrate paleontology at the Royal Ontario Museum (ROM) is the lead author of the study.

“Although Ovatiovermis is no longer than my thumb with all limbs stretched out and is only known from two specimens, this new species provides fantastic new insights into the ecology and relationship of lobopodians, a group of mainly Cambrian marine invertebrates which are key to our understanding of modern tardigrades, onychophorans and the largest group of animals on Earth – the arthropods,” said Caron, a researcher in the departments of ecology and evolutionary biology and earth sciences at U of T's Faculty of Arts & Science.

Caron and Cédric Aria, a PhD candidate in U of T's department of ecology and evolutionary biology, believe that strong recurved claws on the back limbs may have allowed Ovatiovermis and other related species to anchor themselves on hard surfaces and stand more or less upright. Two long pairs of flexible and spinulose (hairy or spiky) limbs at the front of the body would then have been used to filter or collect food from water and bring it closer to the animals’ toothed, eversible mouth.

“The various adaptations of this new animal to anchored particle feeding are reflected in its name,” said Aria, a co-author of the study. “The species, cribratus, is the Latin for “to sieve,” whereas the genus name, Ovatiovermis, refers to that posture it must have ordinarily taken along the bottom of the sea: a worm-like creature that stood in perpetual ovation.”

This specimen, the holotype for “Ovatiovermis cribratus,” was collected in 1994 by the Royal Ontario Museum at the Walcott quarry, located in Yoho National Park, British Columbia (photo by Jean-Bernard Caron ©Royal Ontario Museum)

Even though lobopodians have long been known and studied, and occupy an intriguing position in the tree of life of invertebrate animals, their ecology had remained poorly understood. The authors of the study also think that their findings provide new views on the evolution of lobopodians and their relatives.

“Lobopodians have mostly been seen so far as an eclectic group,” Aria said. “We think that suspension feeding was common among them and turned out to be important in the initial ‘burst’ of that colossal group that gave rise to water bears, velvet worms and arthropods. Interestingly, today, skeleton shrimps (Caprellidae), which are arthropods and thus much more complex living relatives of the lobopodians, have adopted a very similar lifestyle, and you can see them waving in the drifting water possibly much like Ovatiovermis used to.”

Caron said the study also adds to what's known about suspension feeding.

“These results contribute to cumulative evidence that suspension feeding was already a widespread mode of life during the Cambrian period,” Caron said. “Its emergence has been important for the elaboration of modern marine ecosystems and must have played a role in the rapid diversification of the first animals.”

Excavation work in 1994 by a team from the ROM at the Walcott quarry revealed new fossiliferous layers below the Walcott quarry (photo by Desmond Collins ©Royal Ontario Museum)

The researchers were surprised however to find that unlike many other lobopodians, O. cribratus, did not have any hard structures to protect its body.

“Contrary to its relatives, this species does not have any spines or plates on its body for protection,” Caron said. “Its ‘naked’ state begs the question of how it was able to guard against predators.”

The absence of ornament in the new species demonstrates that organisms that lived in the Cambrian period did not exclusively develop hard defensive structures to protect themselves.

The researchers speculate that O. cribratus may have lived in sponge colonies to avoid predators, or that by analogy with modern animals it used camouflage or was toxic or distasteful to predators. However, this is a question that is difficult to solve with fossils, and it may remain forever one of Ovatiovermis’ secrets.

The Burgess Shale, located in Yoho and Kootenay National Parks, is part of the Canadian Rocky Mountain Parks World Heritage Site. The holotype specimen was discovered by the Royal Ontario Museum in the Walcott Quarry, the original Burgess Shale site, in Yoho National Park. It remained the only known specimen of this new species for nearly two decades until a park visitor serendipitously discovered a second specimen while on a recent Parks Canada sponsored guided hike to the Walcott Quarry.

Parks Canada protects the Burgess Shale, and supports peer-reviewed scientific research that continues to enhance our understanding of these rich palaeontological deposits. This new discovery adds another element to the story of early animal evolution that Parks Canada guides share enthusiastically with hundreds of park visitors every year.

Illustration of “Ovatiovermis cribratus” showing how the holotype specimen became trapped in the sediment, partially sideways, before becoming a fossil (illustration by Danielle Dufault ©Royal Ontario Museum)

When snakes had legs: New look at rare fossil reveals clues about early reptiles

krisha — Mon, 27 Jun 2016 13:49:28 +0000

When snakes had legs: New look at rare fossil reveals clues about early reptiles

krisha Mon, 06/27/2016 - 09:49

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The fossil snake Tetrapodophis, as preserved (composite image of part and counterpart) and as reconstructed in life (image by: Alessandro Palci, Michael Caldwell & Michael Lee - Flinders University, University of Alberta and South Australian Museum)

Blake Eligh

Author legacy

Blake Eligh

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Close examination of a rare Brazilian fossil is shedding new light on an enduring controversy in evolutionary thought – why snakes evolved their long, limbless bodies.

At the heart of the controversy is a tiny fossil discovered in Brazil. Known as a squamate, Tetrapdophis amplectus was a snakelike creature that lived about 110 million years ago during the early Cretaceous period. It is is considered one of the oldest snakes and is notable for having four small, paddle-like legs.

Previous research described the creature as a primitive snake and worm-like burrower, suggesting that snakes originally evolved to live underground. However, new findings by a Canadian-Australian research team reveal that the creature was more closely related to aquatic lizards, suggesting that snakes evolved their long bodies for eel-like swimming.

Professor Robert Reisz of U of T Mississauga’s department of biology studied the 20-centimetre-long juvenile specimen first-hand.

“This exquisite tiny fossil is very slender, with limbs that are certainly not suited for burrowing,” Reisz says. “Instead, it shares features with aquatic lizards from the Late Cretaceous. Tetrapodophis may be closely related to snakes and resembles a snake, but probably is not a snake proper.”

Rare find at Burgess Shale: preserved embryos inside 508-million-year-old Waptia fossil

sgupta — Thu, 17 Dec 2015 11:34:10 +0000

Rare find at Burgess Shale: preserved embryos inside 508-million-year-old Waptia fossil sgupta Thu, 12/17/2015 - 06:34

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Royal Ontario Museum)

Sean Bettam

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Sean Bettam

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Hear Marc Laflamme talk about his research on CBC Radio’s Quirks & Quarks program

U of T prof unlocks mystery of an ancient mass extinction

sgupta — Thu, 01 Oct 2015 16:03:47 +0000

U of T prof unlocks mystery of an ancient mass extinction sgupta Thu, 10/01/2015 - 12:03

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(all photos via Marc Laflamme)

Blake Eligh

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Blake Eligh

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�ؿ�ζSM Mississauga paleontologist Marc Laflamme spends his summers exploring the rocky red canyons of Namibia, searching for the faint fossilized remains of a long-extinct and very unusual creature.

Neither animal nor vegetable, the biotas of the Ediacaran period were the earliest large, complex life forms on the planet, dominating salt oceans for nearly 40 million years. Very little is known about the soft-bodied creatures, except that they mysteriously disappeared about 500 million years ago, and have no living relatives today.

While the life of the creatures remains something of a mystery, Laflamme and his colleagues may have unlocked the secret of how and why the Ediacarans died out at the beginning of the Cambrian period. Ecosystem engineering by newly-evolving animals radically changed the Ediacaran environmen, causing the demise of the unusual organisms. The team’s research is published in the September edition of the Proceedings of the Royal Society B.

The researchers examined three theories about why the Ediacaran creatures disappeared.

“We theorized that the disappearance of Ediacarans could be due to a lack of (fossil) preservation, a catastrophic mass extinction due to climate change, or something else,” Laflamme says. The answer, to the team’s surprise, turned out to be the third option.

But before they could prove that theory, the team had to actually locate the fossils. The team looks for subtle tube-like impressions in the rocks by the soft-bodied organisms that lived on the floor of long-gone salt-water bodies.

“It’s a challenge to find fossilized records,” Laflamme says. There are about 50 sites around the world where Ediacaran fossils are found but, according to Laflamme, the Namibian site is a fossil bonanza.

“It marks the boundary of the Ediacaran world and the animal world, so we can study how ecosystems changed,” he says.

Geochemistry ruled out the catastrophic mass extinction theory. “Conducting tests on the chemical composition of the rocks tells us if we were dealing with environments that were oxygenated or undergoing a stressful change,” he says.

Positive results would have shown changes in ancient environments due to massive climate change, a volcanic activity or meteor impacts.

“We looked for evidence in the geochemistry, but our data didn’t show evidence of environmentally-driven extinction.”

But a different look at the fossil record revealed a surprising answer to their query, suggesting that “ecosystem engineering” caused the Ediacaran to disappear.

“Ecosystem engineers are organisms that significantly alter their environment,” Laflamme says. “Clams, for instance, can filter a lot of bacteria and nutrients out of the water, which causes problems for other creatures that need those resources.

“Something came in and shook up the Ediacaran system,” he adds. “We hypothesized that it had to do with the evolution of new life, and asked ourselves, ‘What happens when you introduce new biology to a system?’”

The researchers found fossil evidence of new animals – worms and worm-like animals – burrowing into sediment on the ocean floor.

“We can see trails all over the place, showing evidence of different behaviours like burrowing, feeding and den building,” Laflamme says. “We documented how new populations of Ediacaran biota responded to the presence of things that we knew, for sure, were animal fossils.”

“The new organisms would have disrupted the layer of bacteria along the sea floor that Ediacaran biota likely fed on,” Laflamme says. “It made it difficult for anything that didn’t move to survive.“

Delicate and sedentary, the Ediacarans couldn’t move or adapt, leaving them vulnerable to the effects of emerging new animals that disturbed the ocean environment. Unable to compete with the new animals for ecosystem space for nutrients, for space on the sea floor, and for food and oxygen, the biota were edged out by animals who were better adapted to use the available resources.

Laflamme’s research team included UTM graduate students Thomas Boag and Sara Mason. Funding was provided by Yale Peabody Museum of Natural History, NASA Astrobiology Institute, the Connaught Foundation, National Science and Engineering Research Council of Canada, National Science Foundation-Earth Sciences and the National Geographic Society.

See photos from the team's field research in Namibia

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Darwinius fossil: longer in the tooth than we thought?

sgupta — Mon, 14 Sep 2015 17:15:30 +0000

Darwinius fossil: longer in the tooth than we thought? sgupta Mon, 09/14/2015 - 13:15

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“Our goal as paleontologists is to bring these animals back to life, ” says Associate Professor Mary Silcox (photo by Ken Jones)

Don Campbell

Author legacy

Don Campbell

"Epic" fossil find: at least a dozen new species, thousands of specimens

sgupta — Tue, 11 Feb 2014 11:44:04 +0000

"Epic" fossil find: at least a dozen new species, thousands of specimens sgupta Tue, 02/11/2014 - 06:44

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