Meet Qikiqtania, a fossil fish with the good sense to stay in the water while others ventured onto land

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An artist’s vision of Qikiqtania enjoying its fully aquatic, free-swimming lifestyle. Credit: Alex Boersma, CC BY-ND

Approximately 365 million years ago, one group of fishes left the water to live on land. These animals were early tetrapods, a lineage that would radiate to include many thousands of species including amphibians, birds, lizards and mammals. Human beings are descendants of those early tetrapods, and we share the legacy of their water-to-land transition.

But what if, instead of venturing onto the shores, they had turned back? What if these animals, just at the cusp of leaving the water, had receded to live again in more ?

A new fossil suggests that one fish, in fact, did just that. In contrast to other closely related animals, which were using their to prop their bodies up on the bottom of the water and perhaps occasionally venturing out onto land, this newly discovered creature had fins that were built for swimming.

In March 2020, I was at The University of Chicago and a member of biologist Neil Shubin’s lab. I was working with Justin Lemberg, another researcher in our group, to process a fossil that was collected back in 2004 during an expedition to the Canadian Arctic.

From the surface of the rock it was embedded in, we could see fragments of the jaws, about 2 inches long (5 cm) and with pointed teeth. There were also patches of white scales with bumpy texture. The anatomy gave us subtle hints that the fossil was an early tetrapod. But we wanted to see inside the rock.

So we used a technology called CT scanning, which shoots X-rays through the specimen, to look for anything that might be hidden within, out of view. On March 13, we scanned an unassuming piece of rock that had a few scales on top and discovered it contained a complete fin buried inside. Our jaws dropped. A few days later, the lab and campus shut down, and COVID-19 sent us into lockdown.

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Tom Stewart holds the Qikiqtania fossil. Credit: Stephanie Sang, CC BY-ND

The fin revealed

A fin like this is extremely precious. It can give scientists clues into how were evolving and how they were living hundreds of millions of years ago. For example, based on the shape of certain bones in the skeleton, we can make predictions about whether an animal was swimming or walking.

Although that first scan of the fin was promising, we needed to see the skeleton in high resolution. As soon as we were allowed back on campus, a professor in the university’s department of the geophysical sciences helped us to trim down the block using a rock saw. This made the block more fin, less rock, allowing for a better scan and a closer view of the fin.

When the dust had cleared and we’d finished analyzing data on the jaws, scales and fin, we realized that this animal was a new species. Not only that, it turns out that this is one of the closest known relatives to limbed vertebrates—those creatures with fingers and toes.

We named it Qikiqtania wakei. Its genus name, pronounced “kick-kiq-tani-ahh,” refers to the Inuktitut words Qikiqtaaluk or Qikiqtani, the traditional name for the region where the fossil was found. When this fish was alive, many hundreds of millions of years ago, this was a warm environment with rivers and streams. Its species name honors the late David Wake, a scientist and mentor who inspired so many of us in the field of evolutionary and .






An animation of the pectoral fin of Qikiqtania showing how it was preserved in the rock. Scales are shown in yellow, fin rays in blue, and the endoskeleton in grey. Credit: Tom Stewart

Skeletons tell how an animal lived

Qikiqtania reveals a lot about a critical period in our lineage’s history. Its scales tell researchers unambiguously that it was living underwater. They show sensory canals that would have allowed the animal to detect the flow of water around its body. Its jaws tell us that it was foraging as a predator, biting and holding onto prey with a series of fangs and drawing food into its mouth by suction.

But it is Qikiqtania’s pectoral fin that is most surprising. It has a humerus bone, just as our upper arm does. But Qikiqtania’s has a very peculiar shape.

Early tetrapods, like Tiktaalik, have humeri that possess a prominent ridge on the underside and a characteristic set of bumps, where muscles attach. These bony bumps tell us that early tetrapods were living on the bottom of lakes and streams, using their fins or arms to prop themselves up, first on the ground underwater and later on land.

Qikiqtania’s humerus is different. It lacks those trademark ridges and processes. Instead, its humerus is thin and boomerang-shaped, and the rest of the fin is large and paddle-like. This fin was built for swimming.

Whereas other early tetrapods were playing at the water’s edge, learning what land had to offer, Qikiqtania was doing something different. Its humerus is truly unlike any others known. My colleagues and I think it shows that Qikiqtania had turned back from the water’s edge and evolved to live, once again, off the ground and in open water.






An animation of the full skeleton of Qikiqtania. Credit: Tom Stewart
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Neil Shubin, who found the fossil, pointing across the valley to the site where Qikiqtania was discovered on Ellesmere Island. Credit: Neil Shubin, CC BY-ND

Evolution isn’t a march in one direction

Evolution isn’t a simple, linear process. Although it might seem like early tetrapods were trending inevitably toward life on land, Qikiqtania shows exactly the limitations of such a directional perspective. Evolution didn’t build a ladder towards humans. It’s a complex set of processes that together grow the tangled tree of life. New species form and they diversify. Branches can head off in any number of directions.

This fossil is special for so many reasons. It’s not just miraculous that this fish was preserved in rock for hundreds of millions of years before being discovered by scientists in the Arctic, on Ellesmere Island. It’s not just that it’s remarkably complete, with its full anatomy revealed by serendipity at the cusp of a global pandemic. It also provides, for the first time, a glimpse of the broader diversity and range of lifestyles of fishes at the water-to-land transition. It helps researchers see more than a ladder and understand that fascinating, tangled tree.

Discoveries depend on community

Qikiqtania was found on Inuit land, and it belongs to that community. My colleagues and I were only able to conduct this research because of the generosity and support of individuals in the hamlets of Resolute Bay and Grise Fiord, the Iviq Hunters and Trappers of Grise Fiord, and the Department of Heritage and Culture, Nunavut. To them, on behalf of our entire research team, “nakurmiik.” Thank you. Paleontological expeditions onto their land have truly changed how we understand the history of life on Earth.

COVID-19 kept many paleontologists from traveling and visiting field sites across the world these last few years. We’re eager to return, to visit with old friends and to search again. Who knows what other animals lie hidden, waiting to be discovered inside blocks of unassuming stone.



This article is republished from The Conversation under a Creative Commons license. Read the original article.

Citation:
Meet Qikiqtania, a fossil fish with the good sense to stay in the water while others ventured onto land (2022, July 21)
retrieved 21 July 2022
from https://phys.org/news/2022-07-qikiqtania-fossil-fish-good-ventured.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no

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Hexbyte Glen Cove Fossil named after Nevada brewer who named his beer after it

Hexbyte Glen Cove

Credit: Unsplash/CC0 Public Domain

First, the beer was named for the fossil.

Now, it’s come full circle, as a species of the fossil found in Nevada is named for the maker of the beer.

The first giant creature to inhabit the earth, the ichthyosaur, dominated the earth’s oceans in the Triassic period. Nearly 2.5 million years later, in 1993, Great Basin Brewing Company in Sparks debuted the Ichthyosaur IPA in honor of the extinct creature.

And as of late last year, one of the earliest species of ichthyosaur is now known as Cymbospondylus youngorum —named for Tom and Bonda Young of Great Basin Brewing Company. The name was announced at a ceremony at the Natural History Museum in Los Angeles in December.

The fossil was found in northern Nevada, about 120 miles (193 kilometers) east of Reno, and is currently on display at the Natural History Museum in Los Angeles.

The Youngs started Great Basin Brewing Company in Sparks in 1993. Before making beer, Tom was a geologist. His interest in fossils led him to name one of his first beers after the ichthyosaur.

The ancient leviathan has regional ties. The creature, which pre-dates dinosaurs, lived in what is now Nevada, when the continents were still joined together and Nevada was under an ocean. An ichthyosaur fossil was found in Nevada in 1928 in what is now Berlin-Ichthyosaur State Park near Gabbs, at the site of the largest known concentration of ichthyosaur fossils in the world. One species of ichthyosaur, the Shonisaurus popularis, was named the state fossil in 1977.

A German team searching in Nevada for more fossils learned of the beer, which led them to Great Basin Brewing and the Youngs. In 2011, that team found another ichthyosaur in Nevada, and the Youngs helped the process of excavating and removing it through monetary donations, along with food and beer, and then by transporting the skull of the 55-foot fossil to Los Angeles in a Great Basin beer truck.

In December, the museum honored the Youngs by naming the fossil after them—the “Young” part of the scientific name.

Replicas of the specimen have been delivered to Great Basin and will be on display at the Sparks and Reno locations.

Dr. Martin Sander, paleontologist at the University of Bonn and research associate with the Dinosaur Institute at the Natural History Museum of Los Angeles County, was the lead in digging out the fossil and getting it to the National History Museum.

Sander told the RGJ in 2020 that he was in the Augusta Mountains outside Winnemucca in October 2011, and at an outcropping around 6,000 feet (1,829 meters) in elevation, he spotted what appeared to be fossilized remains of an ichthyosaur spine.

The specimen was excavated from a rock unit called the “Fossil Hill Member” in the Augusta Mountains of Nevada, 41 miles (66 km) northwest of Austin.

Finding it took some digging.

He said only a few vertebrae were exposed on the side of the canyon. However, the anatomy of the vertebrae suggested that the front end of the animal might still be hidden in the rocks.

His crew then went and discovered the skull, forelimbs and chest region.

The next day, with cold and snow closing in, the team packed up the exposed fossils for further research. They returned in 2014 and excavated the rest.

The well-preserved skull, along with part of the backbone, shoulder and forefin, date back to the Middle Triassic (247.2-237 million years ago), and are the earliest case of an ichthyosaur reaching giant proportions.

It was as big as a large sperm whale at nearly 56 feet (17 meters) and is the largest animal yet discovered from that time period, on land or in the sea.

To get the fossil out was an expensive proposition. The crew lived in the desert for several weeks during the excavation, and had to hire a helicopter to help move it.

There was evidence the large, prehistoric, swimming reptile had been pregnant when it died.

The ichthyosaur was the second-oldest pregnant specimen ever found and it was of a species that had never before been identified. It was just one of two major ichthyosaur findings at the location in the Augusta Mountains.

An NHM spokesman said the elongated snout and conical teeth suggest that C. youngorum preyed on squid and fish, but its size meant that it could have hunted smaller and juvenile marine reptiles as well.

Tom Young is ecstatic about the discovery and display of the .

“It just makes my heart sing when I see people, this is one of the top scientists in the world, and he’s bringing it down to my level and I get it,” Young said. “Nevada is such a unique place. This is the first giant. This is pretty cool.”

Young joked that he had a different idea for the name.

“I was voting for ‘Beerosaurus’ personally,” he said.



© 2022 The Associated Press. All rights reserved. T

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Hexbyte Glen Cove Rare fossil reveals prehistoric Melbourne was once a paradise for tropical pig-nosed turtles

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Credit: Hany Mahmoud, Author provided

The pig-nosed turtle, an endangered freshwater turtle native to the Northern Territory and southern New Guinea, is unique in many respects. Unlike most freshwater turtles, it is almost completely adapted to life in water. It has paddle-like flippers similar to sea turtles, a snorkel-like “pig-nose” to help it breathe while staying submerged, and eggs that will only hatch when exposed to the waters of the wet season.

It is also the last surviving species of a group of tropical turtles called the carettochelyids, which once lived throughout the northern hemisphere. Scientists thought pig-nosed turtles only arrived at Australia within the past few millennia, as no pig-nosed turtle fossils had ever been found here—or so we thought.

A 5-million-year-old fossil from Museums Victoria’s collections has now completely rewritten this story. Discovered at Beaumaris, 20km southeast of Melbourne, this fossil lay unidentified in Melbourne Museum’s collection for almost 100 years until our team came across it.

We identified the fossil as a small section of the front of a pig-nosed turtle’s shell, as we report today in the journal Papers in Palaeontology. Although the fossil is just a fragment, we were lucky that it was from a very diagnostic area of the shell.

The fossil shows that carettochelyid turtles have been living in Australia for millions of years. But what was a pig-nosed turtle doing in Beaumaris 5 million years ago, thousands of kilometers from their modern range?

Artist’s impression of the pig-nosed turtle swimming in an ancient river. Credit: Jaime Bran

Well, in the past, Melbourne’s weather was a lot warmer and wetter that it is now. It was more akin to the in which these turtles live today.

In fact, this isn’t the first prehistoric tropical species discovered here: monk seals, which today live in Hawaii and the Mediterranean, and dugongs also once lived in what is now Beaumaris.

A tropical Melbourne?

Millions of years ago, Australia’s eastern seaboard was a tropical turtle hotspot. The warmer and wetter environment would have been perfect for supporting a greater diversity of turtles in the past. This is in stark contrast to modern times; today, Australia is mostly home to the side-necked turtles.

Tropical turtles would have had to cross thousands of kilometers of ocean to get here. But this is not unusual—small animals often cross the sea by hitching a ride on vegetation rafts.

So where are these turtles now? Why is the modern pig-nosed turtle the last remaining species of the carettochelyids? Well, just like today, animals in the past were threatened by . When Australasia’s climate became cooler and drier after the ice ages, all the tropical turtles went extinct, except for the pig-nosed turtle in the Northern Territory and New Guinea.

This also suggests that the modern pig-nosed turtle, already endangered, is under threat from human-driven climate change. These turtles are very sensitive to their environment, and without rain their eggs cannot hatch.

This is true of a lot of Australia’s native animals and plants. In reptile species such as and crocodiles, sex can be determined by the temperature at which eggs are incubated. This is yet another factor that could put these species at risk as the climate changes.

The treasure trove of fossils from Beaumaris shows just how important Australia’s previously tropical environment was for ancient animals. Southern Australia used to be home to many tropical that now have much more restricted ranges.

Just last year, the discovery of tropical monk seals fossils from Beaumaris completely changed how scientists thought seals evolved. This shows just how much we still have to learn about Australia’s prehistoric past, when it was so different from the sunburnt country we know today.



More information:
James P. Rule et al, Turtles all the way down: Neogene pig‐nosed turtle fossil from southern Australia reveals cryptic freshwater turtle invasions and extinctions, Papers in Palaeontology (2021). DOI: 10.1002/spp2.1414

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Citation:
Rare fossil reveals prehistoric Melbourne was once a paradise for tropical pig-nosed turtles (2021, December 11)
retrieved 12 December 2021
from https://phys.org/news/2021-12-rare-fossil-reveals-prehistoric-melbourne.html

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Hexbyte Glen Cove Limiting fossil fuel extraction to keep global warming below 1.5° C target thumbnail

Hexbyte Glen Cove Limiting fossil fuel extraction to keep global warming below 1.5° C target

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Nearly 60% of both oil and fossil methane gas and almost 90% of coal must remain in the ground by 2050 in order to keep global warming below 1.5° C, finds a study by UCL researchers.

Global oil and gas production must decline by 3% annually until 2050 in order to reach this target. Many fossil fuel extraction projects, both planned and operational, are not conducive to meeting internationally agreed target limits on global warming, as set out by the Paris Climate Agreement in 2015. A significant number of regions have therefore already reached peak fossil fuel production, and any increase in production from one region must be offset by a greater production decline elsewhere.

The findings, published in Nature, are based on a 50% probability of limiting warming to 1.5° C this century, meaning that increasing the likelihood of reaching this target would require an even more rapid decline in production and more fossil fuels left in the ground.

The researchers used a global energy system model to assess the amount of fossil fuels that would need to be left unextracted regionally and globally.

The required unextracted reserves are estimated as the percentage of the 2018 reserve base. This needs to be 58% for oil, 59% for fossil methane gas and 89% for coal by 2050.

Lead author Dan Welsby (UCL Institute for Sustainable Resources) says that “in 2015, 196 parties signed the Paris Climate Agreement, aiming to keep average global temperature rise to well-below 2° C, with 1.5° C the desired target. Since then, the IPCC Special Report on 1.5° C, successive Production Gap Reports and the IEA Net Zero Report have indicated beyond doubt that dramatic cuts in fossil fuel production are required immediately in order to move towards net zero emissions, and that current and indicated fossil fuel production trajectories are moving us in the wrong direction.

“Our new paper adds further weight to recent research, indicating that global oil and fossil methane gas production has already peaked. From a regional perspective, our results suggest significant transition risk for large fossil fuel producers. Oil production in the Middle East for example roughly halves between 2020 and 2050, suggesting the diversification of economies away from a dependence on hydrocarbon revenues is absolutely critical.”

The work builds on previous research in 2015, which found that in order to limit warming to 2° C, a third of oil reserves, nearly half of fossil methane gas (49%) reserves and over 80% of coal reserves should remain in the ground.

The researchers used the TIMES Integrated Assessment Model at UCL (TIAM-UCL). The model captures primary energy sources—oil, fossil methane gas, coal, nuclear, biomass and renewables—from production through to conversion (e.g. electricity, hydrogen and biofuel production or oil refining), and distribution to meet a set of demands in each end-use sector.

Countries of the world are represented as 16 regions, which allows for a detailed characterization of regional energy sectors. The model assessed different scenarios including lower demands in key carbon intensive sectors (aviation and chemicals) and uncertainty around the availability and deployment of key carbon capture, utilization and storage (CCUS) and negative emissions technologies (NETs).

In terms of the regional distribution of unextractable fossil fuel reserves, the researchers found that the Middle East must leave around 60% of oil and gas reserves in the ground, which given the large size of its reserve base also results in huge absolute volumes. Additionally, regions with high concentrations of relatively high cost and high carbon intensive deposits of oil within the reserve base show high proportions of unextractable reserves including the oil sands in Canada (83%) and ultra-heavy oil in Central and South America (73%). The regional differences in the proportion of fossil fuels which must remain unextracted is down to a combination of factors including extraction costs, the carbon intensity of production and the costs of alternative technologies to fossil fuels.

Mr. Welsby continued, “We stress that our estimates of unextractable reserves and production decline rates are likely underestimates, given we use a budget consistent with only a 50% chance of meeting 1.5° C and the huge uncertainty around the deployment of negative emission technologies. However, assuming the political will is present to fulfill the commitments made in Paris, the reductions in suggested in our work are entirely feasible.”



More information:
Dan Welsby et al, Unextractable fossil fuels in a 1.5° C world, Nature (2021). DOI: 10.1038/s41586-021-03821-8

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Hexbyte Glen Cove Fossil pigments shed new light on vertebrate evolution thumbnail

Hexbyte Glen Cove Fossil pigments shed new light on vertebrate evolution

Hexbyte Glen Cove

Scanning electron microscope image of melanosomes from a modern bird feather. Credit: UCC

UCC palaeontologists have discovered new evidence that the fate of vertebrate animals over the last 400 million years has been shaped by microscopic melanin pigments.

This new twist in the story of animal is based on cutting-edge analyses of melanin granules—melanosomes—in many different fossil and modern vertebrates, including fish, amphibians, reptiles, birds and mammals. Melanin and melanosomes have traditionally been linked to outermost body tissues such as skin, hair and feathers, with important roles in UV protection and stiffening of tissues. Analyses of where different animals store melanin in the body, however, show that different vertebrate groups concentrate melanin in different organs, revealing shifts in how animals have used melanin over the last 400 million years.

The study, published today in the journal Trends in Ecology and Evolution, was led by UCC palaeontologists Prof. Maria McNamara, Dr. Chris Rogers, Dr. Valentina Rossi and Ph.D. student Tiffany Slater, with an international team of evolutionary biologists from Switzerland.

“Most studies of fossil melanin have focussed on melanin in fossil feathers and skin, and what colors ancient animals had,” said study leader Prof. McNamara. “By comparing melanin in different animals—how much melanin they have, where in the body it occurs, what melanin type and composition is present—and by studying fossils, we discovered new evidence for changes in the functions of melanin through deep time.”

False-colour scanning electron microscope image of melanosomes within a barb of a modern bird feather. Credit: UCC

The research shows that amphibians and reptiles concentrate melanin in internal organs, where it supports the immune system and stores metals. In birds and mammals, however, almost all melanin occurs in hair and feathers. This difference has an unexpected source—evolution of the and of warm-blooded lifestyles.

“There are pros and cons to having melanin in the body,” said team member Dr. Rossi. “Melanin is hugely beneficial, but it also generates free radicals, which are harmful. This creates a major problem for animals.”

During the evolution of hair and feathers, mammals and birds evolved more sophisticated immune systems than in amphibians and reptiles. This meant that large amounts of melanin were no longer necessary in internal organs. Melanin storage then shifted to hair and feathers, which are dead tissues, thereby removing harmful metals and free radicals from living body parts.

“Melanin is a two-sided coin,” said Prof. McNamara. “It’s useful, but toxic. Birds and mammals basically came up with an ingenious solution during the early Triassic—pump melanin into new, outer, dead skin tissues that were evolving at the time. This set the scene for the evolution of the incredible diversity of plumage and fur patterning which we see today.”

The study also shows that key genes can be mapped onto color patterns in fossils, tracking the genetic evolution of melanin through time, and that preferentially use less toxic forms of melanin. “There’s still a lot about genetics and physiology that we don’t understand,” said Dr. Ducrest of Lausanne University. What’s clear, however, is that the fossil record is a valuable source of information that we can use going forwards.”



More information:
M.E. McNamara et al. Decoding the Evolution of Melanin in Vertebrates. Trends in Ecology & Evolution. Published:February 03, 2021 DOI:doi.org/10.1016/j.tree.2020.12.012

Citation:
Fossil pigments shed new light on vertebrate evolution (2021, February 4)
retrieved 4 February 2021
from https://phys.org/news/2021-02-fossil-pigments-vertebrate-evolution.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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