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Meet Saltriovenator: Oldest Known Big Predatory Dinosaur

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Saltriovenator was likely covered with filamentous protoplumage. The presence of horns on the lacrymal and nasal bones is inferred from its close kinship with dinosaurs which possess those cranial onamentation. Credit: Davide Bonadonna.

An artist’s rendering of Saltriovenator includes filamentous protoplumage and horns, the latter suggested by its evolutionary links to species with similar ornamentation. (Credit: Davide Bonadonna)

Paleontologists working in northern Italy have announced the oldest large-size predatory dinosaur known to the fossil record. Saltriovenator zanellai weighed about a ton and, at nearly 200 million years old, predates more famous megapredators by at least 25 million years.

Saltriovenator’s bones are also the first dinosaur remains to preserve evidence of marine animals that gnawed on its carcass. The biggest thing about S. zanellai, however, may be its hands: The animal’s fingers could solve a long-running debate about how bird wings evolved. 

Saltriovenator would be a source of significant national pride at any size: It’s the first Jurassic dinosaur ever found in Italy. But the animal’s robust build and estimated length of more than 24 feet make it especially noteworthy, because other predatory dinosaurs of the period were typically less stocky and much smaller. Even bigger news: Researchers believe the Saltriovenator speciman was a sub-adult, with plenty of growing left to do.

Dined-Upon After Death

The first pieces of the new dinosaur were found in a quarry in 1996 by amateur fossil enthusiast Angelo Zanella. Alas, quarrying explosives had blown apart the fossiliferous layers of rock, splintering many of the bones. Painstaking excavation, preparation and analysis of the material took decades, which is why the find is only being formally named and described now.

Skeletal reconstruction of Saltriovenator zanellai, made by comparing the shape and proportions of the known elements (in orange) with those of more complete skeletons of related species. For scale is Mr. Angelo Zanella (1.67 m tall), who found the dinosaur now named after him. Credit: Marco Auditore

This skeletal reconstruction of S. zanellai uses Angelo Zanella for scale: the amateur paleontologist discovered the animal that now bears his name. Fossil fragments shown in orange belong to Saltriovenator; the rest of the body was determined comparing those pieces with more complete skeletons of related species. (Credit: Marco Auditore)

Eventually, the team recovered 132 fragments, enough to piece together 64 complete or partial bones and confirm nearly all the material was from a single individual. A single tooth and a jaw fragment found with Saltriovenator turned out to be from a bony fish, which hints at the dinosaur’s watery resting place — and a fascinating aspect of the find.

Researchers confirmed at least 30 bore marks on the bones from a variety of marine invertebrates that had nibbled on the carcass. It’s the first time this kind of marine bioerosion has been found on a dinosaur. It suggests that Saltriovenator’s carcass sank to the bottom of a shallow marine basin or similar body of water, and remained partially exposed to scavengers for some time.

Jurassic Spark

Finding a large-body predatory dinosaur from the Early Jurassic could help explain a curious trend in the fossil record from this period. Saltriovenator belongs to one of the major dinosaur lineages: Theropoda. Theropods were almost exclusively meat-eaters, and preyed on another major lineage, the herbivorous sauropodomorphs. The most famous of the sauropodomorphs were also among the last of their line to evolve, and include the aptly-named titanosaurs.

But let’s back up to the Late Triassic, which predates the Jurassic Period. At this time, well over 200 million years ago, most sauropodomorphs were significantly smaller than the giants that evolved much later. (There are a couple exceptions, such as Argentina’s Ingentia prima, described earlier this year.) Then, suddenly, in the Early Jurassic — when Saltriovenator was around — the sauropodomorphs start getting bigger and bigger.

A number of explanations for this trend toward gigantism have been proposed, but the discovery of Saltriovenator suggests that predator and prey may have been engaged in a size-based arms race during the Early Jurassic.

Winging It

While its size in life (and the evidence of what ate it after death) are intriguing, the most scientifically significant thing about Saltriovenator may be the story told in its fingers. Birds are the lone surviving dinosaur lineage; more specifically, they’re the last theropod dinosaurs around. How the earliest birds evolved wings is one of the most contentious hot spots in the field, right up there with the evolution of feathers.

Some researchers believe that bird wings are the result of the first, second and third digits of the theropod hand becoming fused; others think the fusion was of the second, third and fourth digits. According to the authors of today’s study, Saltriovenator, which had a stubby fourth digit, provides supporting evidence for the hypothesis that modern bird wings evolved from the first, second and third digits of a distant theropod ancestor.

This digit debate may sound like a minor issue to casual dinosaur fans, but supporting evidence for either hypothesis can be found in both the fossil record and developmental research into modern bird embryos. Figuring out how bird wings evolved could provide us with a better idea of how specific traits emerge in a species.

The open-access study appears today in PeerJ.

Simplified evolutionary tree of predatory dinosaurs (theropods). Saltriovenator predates the massive meat-eating dinosaurs by over 25 million years: it is the oldest known ceratosaurian, and the world’s largest predatory dinosaur from the Lower Jurassic. During the Jurassic, the three- fingered tetanuran theropods appeared, which gave rise to birds. Credit: Andrea Cau.

Saltriovenator is the world’s biggest Early Jurassic predatory dinosaur, showing up in the fossil record more than 25 million years before other predators of a similar size. Its forelimbs had four digits, which helped authors determine it was not a three-fingered tetanuran dinosaur, the lineage from which birds evolved. Despite being merely a distant cousin of birds, Saltriovenator’s anatomy may solve a debate over how those living dinosaurs came to be. (Credit: Andrea Cau)

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Ecology

Today’s letters: ‘Visionary’ plans don’t always work in Ottawa

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The opinion piece written by Tobi Nussbaum, CEO of the NCC, declares that a “bold, visionary transit plan” would showcase the capital.

As a long-term resident of Ottawa, I’ve had it with visionary plans. In the 1950s, the streetcars serving Ottawa so well were sent to the scrapyards. In the early ’60s, Queensway construction bulldozed established neighbourhoods and ripped the city apart. Later in the decade, the downtown railway station, which could have formed the hub of a commuter network, was relocated to the suburbs. These actions, in the name of “progress,” were undertaken with the “vision” to make Ottawa a car-reliant city.

Now we have an LRT, built just in time for most people to realize that they do not have to go downtown as they can work from home.

Current thinking is pushing a new “link” between Ottawa and Gatineau, with yet more expensive and disruptive infrastructure projects being touted, including a tramway or another tunnel under the downtown core.

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Ecology

That was then: Biggest earthquake since 1653 rocked Ottawa in 1925

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A regular weekly look-back at some offbeat or interesting stories that have appeared in the Ottawa Citizen over its 175-year history. Today: The big one hits.

The Ottawa Senators were playing a Saturday night game against the Montreal Canadiens at the Auditorium, the score tied 0-0 halfway through the second period. Sens’ rookie Ed Gorman and the Habs’ Billy Boucher had just served penalties for a dustup when the building began to make “ominous creaking sounds.” A window crashed to the ground.

Nearby, at Lisgar Collegiate, all eyes were on teenager Roxie Carrier, in the role of Donna Cyrilla in the musical comedy El Bandido. She had the stage to herself and was singing “Sometime” when the building rocked, the spotlight went out, and someone in the audience yelled “Fire!”

At a home on Carey Avenue, one woman’s normally relaxed cat suddenly arched its back, rushed around the room two or three times, spitting angrily, and climbed up the front-window curtains.

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Ecology

Ottawa delays small nuclear reactor plan as critics decry push for new reactors

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TORONTO — Canadians will have to wait a little while longer to see the federal government’s plan for the development of small nuclear reactors, seen by proponents as critical to the country’s fight against global warming.

Speaking at the opening of a two-day virtual international conference on Wednesday, the parliamentary secretary to the minister of natural resources said the plan will lay out key actions regarding the reactors. Its launch, Paul Lefebvre said, would come in the next few weeks.

“We’re still putting the finishing touches on it,” Lefebvre said. “The action plan is too important to be rushed.”

Small modular reactors — SMRs — are smaller in size and energy output than traditional nuclear power units, and more flexible in their deployment. While conventional reactors produce around 800 megawatts of power, SMRs can deliver up to 300 megawatts.

Proponents consider them ideal as both part of the regular electricity grid as well as for use in remote locations, including industrial sites and isolated northern communities. They could also play a role in the production of hydrogen and local heating.

“SMRs will allow us to take a bold step of meeting our goal of net-zero (emissions) by 2050 while creating good, middle class jobs and strengthening our competitive advantage,” said Lefebvre.

Natural Resources Minister Seamus O’Regan had been scheduled to speak at the conference but did not due to a family emergency.

Industry critics were quick to pounce on the government’s expected SMR announcement. They called on Ottawa to halt its plans to fund the experimental technology.

While nuclear power generation produces no greenhouse gas emissions, a major problem facing the industry is its growing mound of radioactive waste. This week, the government embarked on a round of consultations about what do with the dangerous material.

Dozens of groups, including the NDP, Bloc Quebecois, Green Party and some Indigenous organizations, oppose the plan for developing small modular reactors. They want the government to fight climate change by investing more in renewable energy and energy efficiency.

“We have options that are cheaper and safer and will be available quicker,” Richard Cannings, the NDP natural resources critic, said in a statement.

Lefebvre, however, said the global market for SMRs is expected to be worth between $150 billion and $300 billion a year by 2040. As one of the world’s largest producers of uranium, Canada has to be part of the wave both for economic and environmental reasons, he said.

“There’s a growing demand for smaller, simpler and affordable nuclear technology energy,” Lefebvre said.

Joe McBrearty, head of Canadian Nuclear Laboratories, told the conference the company had signed a host agreement this week with Ottawa-based Global First Power for a demonstration SMR at its Chalk River campus in eastern Ontario. A demonstration reactor will allow for the assessment of the technology’s overall viability, he said.

“When talking about deploying a new technology like an SMR, building a demonstration unit is vital to the success of that process,” McBrearty said. “Most importantly, it allows the public to see the reactor, to kick the tires so to speak, and to have confidence in the safety of its operation.”

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