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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

Globe Climate: Canada’s resource reckoning is coming

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Good afternoon, and welcome to Globe Climate, a newsletter about climate change, environment and resources in Canada.

This afternoon, the Alberta government announced that it is restoring a coal mining policy it revoked last spring. At the time, the move provoked a widespread public backlash detailed by The Globe. The original decision, which opened up more than 1.4 million hectares to exploration, was made without public consultation. Premier Jason Kenney previously defended the changes.

Lots more on coal and Canada’s resources industry in this week’s newsletter edition.

Now, let’s catch you up on other news.

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Ecology

‘Incredibly destructive’: Canada’s Prairies to see devastating impact of climate change

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As the climate continues to warm at an alarming rate, experts warn if dramatic steps to mitigate global warming are not taken, the effects in Canada’s Prairie region will be devastating to the country’s agriculture sector.

According to Environment and Climate Change Canada, the country is warming, on average, about double the global rate.

Scientists with the National Oceanic and Atmospheric Administration in the U.S. recently found 2020 was earth’s second-hottest year on record, with the average land and ocean surface temperature across the globe at 0.98 of a degree C above the 20th-century average.

However, the agency found the northern hemisphere saw its hottest year on record, at 1.28 degrees C above the average.

“(In Canada) we are looking at about 6.4C degrees of warming this century, which isn’t much less than one degree per decade, which is just a terrifying rate of warming,” Darrin Qualman, the director of climate crisis policy and action at the National Farmer’s Union said.

Qualman said there is “massive change coming” to Canada’s Prairies, which will be “incredibly destructive.”

“It’s not going too far to say that if we made that happen, parts of the Prairies wouldn’t be farmable anymore,” he said.

According to the federal government, in 2018 Canada’s agriculture and agri-food system generated $143 billion, accounting for 7.4 per cent of the country’s GDP.

The sector employed 2.3 million people in 2018. The majority of the 64.2 million hectares of farmland in Canada is concentrated in the Prairies and in southern Ontario.

The effects of climate change are already being felt on the ground in the Prairies, Qualman said, adding that the NFU has already heard from farmers complaining of “challenging weather.”

“People are sharing pictures of flattened crops and buildings, et cetera, that have been damaged,” he said. “And we’re still at the beginning of this.”

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Ecology

Insect-based dog food aims to cut your pet’s carbon pawprint

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Meat has an enormous carbon footprint, with livestock liable for about 15 per cent of worldwide emissions, as we have beforehand mentioned on this e-newsletter. That is prompted specialists to suggest consuming much less meat for sustainability (and well being) causes.

However what about your pet? One research discovered that the methane and nitrous oxide emissions generated by canine and cat meals within the U.S. alone had been equal to about 64 million tonnes of CO2, or roughly the quantity produced by 13.6 million automobiles. And it might be getting worse, with a development towards feeding pets “human-grade” meat.

That is prompted some pet meals makers to look to lower-carbon protein sources — together with bugs.

Research present that producing insect-based meals requires far much less feed, land and water and generates far fewer greenhouse fuel emissions per kilogram than meats comparable to beef, pork or rooster.

That is one of many causes increasingly more pet meals containing insect protein are hitting the market. Purina, a model owned by multinational Nestlé, launched a line of canine and cat meals containing black soldier fly larvae in Switzerland in November.

In Canada, Montreal-based Wilder Harrier began promoting canine treats made with cricket protein in 2015 and pet food made with black soldier fly larvae in 2019. It plans to broaden to launch a line of insect-based cat treats later this yr and cat meals in 2022 due to “a ton of demand,” mentioned firm co-founder Philippe Poirier.

Wilder Harrier initially labored with animal nutritionists on insect-based merchandise to unravel a unique downside — specifically, the founders’ canines had allergy symptoms to frequent meats utilized in canine meals. Poirier mentioned now about half its prospects hunt down the product due to their pets’ allergy symptoms and about half for environmental causes.

Dr. Cailin Heinze, a U.S.-based veterinary nutritionist licensed by the American School of Veterinary Vitamin, has written concerning the environmental influence of pet meals. She mentioned we’re typically “not as involved as we probably ought to [be]” concerning the environmental footprint of pets.

Alternatively, she famous that the longer-term influence of newer diets, comparable to vegan meals and people containing bugs, hasn’t been nicely examined in comparison with conventional pet meals.

Maria Cattai de Godoy, an assistant professor of animal sciences on the College of Illinois who research novel proteins for pet meals (together with bugs, yeast and plant-based substances), mentioned such substances are rigorously examined to find out their security and diet earlier than being added to pet meals. 

“This can be a very extremely regulated trade,” she mentioned, however admitted it is also evolving.

Relating to bugs, she mentioned constructive information “reveals promise in direction of utilizing them increasingly more in pet meals.” Insect-based proteins have additionally earned the endorsement of the British Veterinary Affiliation, which says some insect-based meals could also be higher for pets than prime steak.

However Godoy famous that there isn’t any one-size-fits-all resolution, and pet homeowners ought to take into consideration the wants of their very own particular person pet and analysis whether or not a specific weight loss plan can be appropriate.

She mentioned that other than the kind of protein, issues like packaging and manufacturing strategies may also make a distinction. For instance, utilizing meat byproducts that may in any other case turn into waste would not drive elevated meat manufacturing the identical approach as utilizing human-grade meat.

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