Tyrannosaurus is a large dinosaur family including Tyrannosaurus Rex , Fear Dragon , Tyrannosaurus , Alberta dragon, Snake-haired female monster dragon, etc. Its characteristics are huge heads and short forelimbs. Although they have been discovered in North America and Asia for more than a century, many details about their evolutionary history are still unclear.
Tyrannosaurus, which is fighting for prey,
Feared Dragon is a famous large tyrannosaurus in North America and is the largest predator in its era. There are currently two species of Daspletosaurus, namely the pattern speciesDaspletosaurus torosus and the classified speciesDaspletosaurus (Daspletosaurus horneri). Since the 1990s, there has been debate over whether the fear dragon and Tyrannosaurus rex represent in-situ evolution (linear evolution) of a single lineage or several closely related species (branch evolution) from different lineages is limited by the scarcity of intact fossil specimens.
Recently, Warshaw, a researcher at Montana State University in the United States, and Fowler, director of the Wasteland Dinosaur Museum, jointly reported a newly discovered dinosaur fossil-Daspletosaurus wilsoni, providing new evidence to resolve the above dispute.
Wilson Fearing Dragon Head Recovery Diagram
The newly discovered Wilson Fearing Dragon is named after the discoverer of the specimen, John "Jack" P. Wilson, a staff member of the Wasteland Dinosaur Museum. In 2017, a small flat bone was found at the bottom of a towering cliff northeast of Montana. This unique flat bone is the middle part of the nostril of the Tyrannosaurus. After careful excavation, a complete premaxillary bone was also found around the bone. Some broken vertebrae from the site indicated that it was a large Tyrannosaurus, covered with rocks up to 8 meters thick above the fossil. In 2020 and 2021, staff used a jackhammer to dig into the rock formation where the bones were located and found some skulls and other bones.
Wilson's left upper maxilla bone
This time the fossil collection was very difficult, and the staff nicknamed this dinosaur specimen " Sisyphus ". Sisyphus is a king in Greek mythology who violated the gods by deceiving death. In order to punish Sisyphus, the gods asked him to push a huge rock to the top of the mountain. Because the huge rock was too heavy, they rolled down the mountain before they reached the top of the mountain, and all their previous efforts were wasted, so he kept repeating and never ending in doing this. The staff felt that removing the thick rock layer above the specimen seemed to be an endless task, so they called it "Sisyphus."
staff members were extracting Wilson's dragon fear specimens
Wilson's dragon fear discovery is of great significance to scientific researchers because it provides a "missing link" for studying the evolutionary lineage of Tyrannosaurus Rex. Wilson's Feared Dragon, which is from the Judith River Formation, dates to about 76.5 million years ago, shows mixed features found in more primitive Tyrannosaurus, such as a set of prominent horns around the eyes, while also possessing known features of late members of the group, including Tyrannosaurus Rex, such as tall eye sockets and expanded air pockets in the skull.
Wilson's Dragon Fear Skull
From the perspective of form and era, Wilson's Dragon Fear is located between the strong Dragon Fear (77 million years ago) and the Huo's Dragon Fear (75.6 million years ago), making up for the "missing link" between the older and younger Dragon Fear. This suggests that the phobia has undergone a single lineage evolution, i.e., from one form to another without producing new branches.
In North America in the Late Cretaceous North America, there are several closely related dinosaur species that were previously believed to be representative of dinosaur diversity , i.e. they lived in the same period, using it as evidence of the evolution of dinosaur branches. However, the discovery of a large number of new specimens and their corresponding exact time points have changed the researchers' minds.
Nowadays, from the exact point in time, many dinosaur species are actually in different periods and can form a continuous single evolutionary lineage in which one of the ancestors evolves directly into offspring species.This "linear evolution" model, contrary to "branch evolution", in which successive branch events produce many closely related species, those that appear to be similar to each other, represent evolutionary "cousin" rather than ancestors and descendants. The research results support Tyrannosaurus rex as a descendant of the fear dragon rather than its cousin.
phylogeny location
This new study supports the addition of Tyrannosaurus to a growing list of dinosaurs, including horned dinosaurs and duck-billed dinosaurs, which have been proposed to undergo linear evolution. This seems to suggest that the "linear evolution" pattern is more common in dinosaurs, and the "branch evolution" pattern may not be as frequent as previously thought.
The above research results were recently published in the journal PeerJ.
Paper information: Warshaw Elías A., Fowler Denver W.. 2022. A transitional species of Daspletosaurus Russell, 1970 from the Judith River Formation of eastern Montana. PeerJ, DOI: 10.7717/peerj.14461
Source: sci.news, phys.org, cnBeta.com, Baidu Encyclopedia, Warshaw et al., 2022
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