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Tyrannosaurus rex
#46
Teenage T. rex was already chomping on prey, new research shows

March 11, 2019 by Natalie Johnson, University of Wisconsin Oshkosh

[Image: teenagetrexw.jpg]
Joseph Peterson, a vertebrate paleontologist at the University of Wisconsin Oshkosh, demonstrates how a T. rex takes a bite. Credit: Patrick Flood, UW Oshkosh

New research from the University of Wisconsin Oshkosh indicates that even as a teenager the Tyrannosaurus rex showed signs that it would grow up to be a ferocious predator.

In a study published last week in the peer-reviewed journal Peerj—the Journal of Life and Environmental Sciences, UWO scientists reported evidence that a juvenile T. rex fed on a large plant-eating dinosaur, even though it lacked the bone-crushing abilities it would develop as an adult.

While studying fossils from an Edmontosaurus—a plant-eating Hadrosaurid or duck-billed dinosaur, UWO vertebrate paleontologist Joseph Peterson noticed three large, v-shaped, bite marks on a tail bone and wondered, "Who made these?"

Peterson knew that T. rex—a member of the meat-eating dinosaur suborder known as Theropoda—was "a likely culprit."

"We suspected that T. rex was responsible for the bit marks, because in the upper Cretaceous rock formation, where the hadrosaur was discovered, there are only a few carnivorous dinosaurs and other reptiles in the fossil record. Crocodile fossils are found there, but such a crocodile would have left tooth marks that are round rather than the elliptical punctures we found on the vertebra," Peterson explained.

"There also were small Velociraptor-like dinosaurs, but their teeth are too small to have made the marks. Finally, an adult T. rex would have made punctures that would have been too large! That's when we started considering a juvenile tyrannosaur."

[Image: 1-teenagetrexw.jpg]
UW Oshkosh researchers made a silicone peel of puncture marks to help determine their origin. Credit: Patrick Flood, UW Oshkosh

To test the hypothesis, Peterson and geology student Karsen Daus, of Suamico, coated the fossil with a silicon rubber to make a silicone peel of the puncture marks.

They found that the dimensions of the "teeth" better matched a late-stage juvenile T. rex (11 to 12 years) than an adult (approximately 30 years).

"Although this T. rex was young, it really packed a punch," Peterson said.

"This is significant to paleontology because it demonstrates how T. rex—the most popular dinosaur of all time—may have developed changes in diet and feeding abilities while growing," he said. "This is part of a larger, ongoing research initiative by many paleontologists to better understand how T. rex grew and functioned as a living creature over 65 million years ago."

Most theropod feeding traces and bite marks are attributed to adults; juvenile tooth marks rarely have been reported in the literature, he added.

"We really are in the 'Golden Age' of paleontology," Peterson said. "We are learning more now than we ever thought we would know about dinosaurs. And, we're learn more about how they grew up."

https://phys.org/news/2019-03-teenage-re...-prey.html



Journal Reference:
Joseph E. Peterson et al, Feeding traces attributable to juvenile Tyrannosaurus rex offer insight into ontogenetic dietary trends, PeerJ (2019). DOI: 10.7717/peerj.6573

Abstract
Theropod dinosaur feeding traces and tooth marks yield paleobiological and paleoecological implications for social interactions, feeding behaviors, and direct evidence of cannibalism and attempted predation. However, ascertaining the taxonomic origin of a tooth mark is largely dependent on both the known regional biostratigraphy and the ontogenetic stage of the taxon. Currently, most recorded theropod feeding traces and bite marks are attributed to adult theropods, whereas juvenile and subadult tooth marks have been rarely reported in the literature. Here we describe feeding traces attributable to a late-stage juvenile Tyrannosaurus rex on a caudal vertebra of a hadrosaurid dinosaur. The dimensions and spacing of the traces were compared to the dentition of Tyrannosaurus rex maxillae and dentaries of different ontogenetic stages. These comparisons reveal that the tooth marks present on the vertebra closely match the maxillary teeth of a late-stage juvenile Tyrannosaurus rex specimen histologically determined to be 11–12 years of age. These results demonstrate that late-stage juvenile and subadult tyrannosaurs were already utilizing the same large-bodied food sources as adults despite lacking the bone-crushing abilities of adults. Further identification of tyrannosaur feeding traces coupled with experimental studies of the biomechanics of tyrannosaur bite forces from younger ontogenetic stages may reveal dynamic dietary trends and ecological roles of Tyrannosaurus rex throughout ontogeny.

https://peerj.com/articles/6573/
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#47
Has anyone read or got access to this article? https://onlinelibrary.wiley.com/doi/pdf/...2SdLNlBX9Q apparently Scotty is now larger than Sue I know that Scotty is simular to Sues size but now it's apparently dethroned Sue coming from some that have read the article I can't read it however.

EDIT
Someone was kind enough to send the article with out pay wall it seems very likely that Scotty was the heaviest Tyrannosaurus specimen known at around 8870 kgs
https://drive.google.com/file/d/15y4u7it...l1_u2xs_98
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#48
(03-23-2019, 02:14 AM)Jurassicdangerousdinosaur Wrote: Has anyone read or got access to this article? https://onlinelibrary.wiley.com/doi/pdf/...2SdLNlBX9Q apparently Scotty is now larger than Sue I know that Scotty is simular to Sues size but now it's apparently dethroned Sue coming from some that have read the article I can't read it however.

EDIT
Someone was kind enough to send the article with out pay wall it seems very likely that Scotty was the heaviest Tyrannosaurus specimen known at around 8870 kgs
https://drive.google.com/file/d/15y4u7it...l1_u2xs_98

Great find. Here is an artcle discussing this find:

Paleontologists report world's biggest Tyrannosaurus rex
Nicknamed 'Scotty,' the record-breaking rex is also the largest dinosaur skeleton ever found in Canada

Date: March 22, 2019
Source: University of Alberta

[Image: 190322163331_1_900x600.jpg]
The towering and battle-scarred 'Scotty' reported by UAlberta paleontologists is the world's largest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada.
Credit: Amanda Kelley

University of Alberta paleontologists have just reported the world's biggest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada. The 13-metre-long T. rex, nicknamed "Scotty," lived in prehistoric Saskatchewan 66 million years ago.
"This is the rex of rexes," said Scott Persons, lead author of the study and postdoctoral researcher in the Department of Biological Sciences. "There is considerable size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty exemplifies the robust. Take careful measurements of its legs, hips, and even shoulder, and Scotty comes out a bit heftier than other T. rex specimens."
Scotty, nicknamed for a celebratory bottle of scotch the night it was discovered, has leg bones suggesting a living weight of more than 8,800 kg, making it bigger than all other carnivorous dinosaurs. The scientific work on Scotty has been a correspondingly massive project.
The skeleton was first discovered in 1991, when paleontologists including T. rex expert and UAlberta professor Phil Currie were called in on the project. But the hard sandstone that encased the bones took more than a decade to remove -- only now have scientists been able to study Scotty fully-assembled and realize how unique a dinosaur it is.
It is not just Scotty's size and weight that set it apart. The Canadian mega rex also lays claim to seniority.
"Scotty is the oldest T. rex known," Persons explains. "By which I mean, it would have had the most candles on its last birthday cake. You can get an idea of how old a dinosaur is by cutting into its bones and studying its growth patterns. Scotty is all old growth."
But age is relative, and T. rexes grew fast and died young. Scotty was estimated to have only been in its early 30s when it died.
"By Tyrannosaurus standards, it had an unusually long life. And it was a violent one," Persons said. "Riddled across the skeleton are pathologies -- spots where scarred bone records large injuries."
Among Scotty's injures are broken ribs, an infected jaw, and what may be a bite from another T. rex on its tail -- battle scars from a long life.
"I think there will always be bigger discoveries to be made," said Persons "But as of right now, this particular Tyrannosaurus is the largest terrestrial predator known to science."
A new exhibit featuring the skeleton of Scotty is set to open at the Royal Saskatchewan Museum in May 2019.


Story Source: University of Alberta. "Paleontologists report world's biggest Tyrannosaurus rex: Nicknamed 'Scotty,' the record-breaking rex is also the largest dinosaur skeleton ever found in Canada." ScienceDaily. www.sciencedaily.com/releases/2019/03/190322163331.htm (accessed March 22, 2019).



Journal Reference:
  1. W. Scott Persons, Philip J. Currie, Gregory M. Erickson. An Older and Exceptionally Large Adult Specimen of Tyrannosaurus rex. The Anatomical Record, 2019; DOI: 10.1002/ar.24118
Abstract
Here we describe an extremely large and relatively complete (roughly 65%) skeleton of Tyrannosaurus rex (RSM P2523.8). Multiple measurements (including those of the skull, hip, and limbs) show that RSM P2523.8 was a robust individual with an estimated body mass exceeding all other known T. rex specimens and representatives of all other gigantic terrestrial theropods. Histological sampling of the fibula confirms that RSM P2523.8 is skeletally mature. The prevalence of incompletely coossified elements contradicts previous assertions that such unfused elements can be taken as indicators of somatic immaturity. As an extreme example of both ontogenetic maturity and osteological robustness, RSM P2523.8 offers support for prior hypotheses that a sampling bias occurs throughout the Dinosauria, making it likely that most taxa grew to significantly greater size than current known specimens indicate.


https://onlinelibrary.wiley.com/doi/abs/...2/ar.24118
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#49
I seriously doubt Scotty being 13 meters long the last time I checked it was around 12 to 12.1 meters long but it definitely is more robust than Sue. Sue is around 8828 kgs while Scotty is now around 8870 kgs crazy big.
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#50
(Yesterday, 01:42 AM)Jurassicdangerousdinosaur Wrote: I seriously doubt Scotty being 13 meters long the last time I checked it was around 12 to 12.1 meters long but it definitely is more robust than Sue. Sue is around 8828 kgs while Scotty is now around 8870 kgs crazy big.
It is likely that they just rounded up the number in the press. But yeah, it's crazy how T-rex keeps got upsizing as oppose to the downsizing trend we are currently having.
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#51
I honestly believe the 90s and early 2000s were a time where certain paleontologists were determined to finally find a theropod that dethroned Tyrannosaurus and certain animals were over exaggerated in the proces.

Giganotosaurus for example I always read it was 13 to 14 meters long and 8 to 10 tons but turns out it really is not that large when looking at the evidence we have now.

Yeah it's possible these theropods could grow larger than T. Rex but sadly our sample size is just to small to really know. And going from how Tyrannosaurus is built I just don't see any theropod being truly larger than it.
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#52
(Yesterday, 02:15 AM)Jurassicdangerousdinosaur Wrote: I honestly believe the 90s and early 2000s were a time where certain paleontologists were determined to finally find a theropod that dethroned Tyrannosaurus and certain animals were over exaggerated in the proces.
I don't think any paleontologists would care about the whole 'dethrone' thing tbh. The reasons for those exaggeration are probably:
1. Imagine you are a paleontologist in the field, you have been digging your ass off for several days under the scorching sun and you found nothing but stones and dusts. And on one magical day, you stumbled across a Theropod femur bone that is longer than that of Sue (Giga holotype does have longer femur than Sue), you would lose your sh*t!. Your excitement would cause your judgement to be deteriorated, thus you ended up overestimating the specimen by using less than desired methods (such as isometrical scaling of femur length). Remember when they first discovered Patagotitan and they also announced it as the biggest Dinosaur, do see similar trend here? 

2. Well, everyone wants to have the biggest 'dick' (if you know what i mean), even scientists. Everyone wants the Dinosaur they discovered and named to be the biggest and the baddest. These factors can also clouded their judgments and their supposed un-biasness.

Of course, after all of the excitements are gone, scientists starts to look at things more objectively and downsizing bans start to happen.
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#53
Yeah i guess what you said makes more sense i mean who does not want to be the paleontologist that finds a larger theropod than Tyrannosaurus ? and when you find certain bones that are larger than the ones in Sue your bound to get excited really.
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#54
Does anyone here know just how long Scotty is ? the last time i checked it was 12 to 12.1 meters long but now everywhere has it listed at 13 meters long even Wikipedia now has the specimen at 13 meters long i seriously doubt its that long. It would be pretty awesome if it was but going from every other Tyrannosaurus specimen we have and the other big theropods we have i cant see Scotty being 13 meters im pretty sure it would weigh over 10 tons if it was.
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