Like its distant relative T. Rex, a newly established dinosaur, named Gualicho shinyae, sported tiny arms and also hands through two clawed fingers


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Tyrannosaurus rexwasn"t the only meat-eating menace with teeny-tiny arms.

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Like its remote relative,T. Rex, a newly established dinosaur, namedGualicho shinyae,sported tiny arms and also hands v two clawed fingers.

"We"re slowly getting an ext information top top this type of sample of body reduction, and also getting in ~ this concern of why tyrannosaurs and some various other theropods shortened your forelimbs," claimed study corresponding author Peter Makovicky, curator the dinosaurs at the field Museum in Chicago. Gualicho shinyae>

G. Shinyaebelonged come a group called the allosaurs and also lived around 90 million year ago, duringthe Cretaceous period. That"s a an excellent 23 million year beforeT. Rexentered the scene in between 67 million and 65 million years ago.

Because they are only distantly connected (both are taken into consideration theropods, which are bipedal and also mostly carnivorous dinosaurs), the two varieties likely emerged their small arms and two-digit hands separately due to similar evolutionary pressure — a procedure called convergent evolution, the researchers said.

Bony discovery

Study lead author Sebastia?n Apestegui?a, a paleontologist through the natural History foundation (AZARA) in Buenos Aires, Argentina, and a team of researchers found the dinosaur along the north edge the a large reservoir in Patagonia, Argentina, in 2007. (In fact, five other predatory dinosaurs have likewise been discovered in the area, called the Huincul Formation.)

"Unfortunately, it"s one of those specimens the was found probably 50 years also late," Makovicky said Live Science. "We have the hind limbs and the forelimbs, we have actually the section of the back and the tail, a small bit that the hips." however they couldn"tlocate the skulland lot of the vertebral column, likely since of erosion.

However, based on what they found, and also the anatomy of various other allosaurus dinosaurs, they estimate that at its hipsG. Shinyaewas about 6 feet (1.8 meters) tall, and that the measured about 25 feet (7.6 m) long and also weighed around 1 metric ton (1.1 tons), Makovicky said.

"It"s no a giant animal by dinosaur standards, yet not small, either, for this reason a midsize predator," that said.

G. Shinyaeis additionally a bizarre mosaic of different dinosaurs. The looks a little likeCarcharodontosaurus, one more carnivorous theropod, also asDeltadromeus(delta runner), a carnivorous dinosaur with slender arms discovered in Africa, i m sorry is perhaps a close relative, the researchers said.

Divine inspiration

Researchers named the dinosaurGualicho shinyaeafter two women: The genus honors Gualichu, a goddess of pets who to be revered by the Tehuelche civilization of Patagonia. Once Europeans carried Christianity come the area, the freshman reinterpreted Gualichu as a demonic entity, the researchers composed in the study.

The paleontologists joked that Gualichu had put a curse on them throughout their fieldwork, after your truck flipped end (no one was seriously hurt), Makovicky said. The types name honors Akiko Shinya, who discovered the specimen.

The newfound dinosaur is an interesting find, claimed Thomas Carr, an associate professor that biology in ~ Carthage college in Wisconsin, who was not connected in the study.

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"It really offers a sharper focus on the totality phenomenon that forelimb reduction and also finger ns in theropods," Carr said. "It plainly occurs throughout many various lineages for different reasons and in various ways."

It also shows that "tyrannosaurs" really aren"t unusual," Carr said. "It"s not simply a one-off."

The brand-new study was published online today (July 13) in thejournal PLOS ONE.