What induced holes in Sue the T. rex’s jawbone? Scientists are stumped By Reuters

By Will Dunham

WASHINGTON (Reuters) – Sue, the largest and finest preserved Tyrannosaurus rex ever unearthed, little question was a fearsome beast when this predator prowled what’s now South Dakota about 67 million years in the past on the twilight of the age of dinosaurs.

However even this enormous dinosaur, whose fossils are displayed on the Subject Museum in Chicago, was not invulnerable. A chief instance of that is the sequence of round holes in Sue’s jawbone that proceed to baffle scientists. New analysis searching for an evidence for these holes has managed to rule out one main speculation, although the reply stays elusive.

Researchers mentioned an in depth examination of the eight holes – some the diameter of a golf ball – on the again half of Sue’s left decrease jawbone, or mandible, decided that they weren’t attributable to a kind of microbial an infection as some specialists had proposed.

The holes had been discovered to vary from bone injury attributable to such an an infection, mentioned Bruce Rothschild, a medical physician and analysis affiliate on the Carnegie Museum of Pure Historical past in Pittsburgh, lead creator of the examine printed this week within the journal Cretaceous Analysis.

Sue, measuring 40-1/2 ft lengthy (12.3 meters), represents one of many world’s best-known dinosaur fossils. Tyrannosaurus was one of many largest land predators ever, inhabiting western North America on the finish of the Cretaceous Interval.

Subject Museum paleontologist and examine co-author Jingmai O’Connor famous that about 15% of all recognized T. rex specimens have holes just like Sue’s.

The researchers explored whether or not the holes had been attributable to an an infection involving microbes referred to as protozoans. One widespread protozoan illness recognized to happen in birds, which advanced from feathered dinosaurs, in addition to in folks known as trichomoniasis, attributable to a parasitic protozoan. Trichomoniasis in folks, although not birds, is a sexually transmitted illness.

O’Connor famous that one falcon recognized with trichomoniasis had proven injury in its jaw, but it surely differed from Sue’s holes.

The bone round Sue’s holes confirmed indicators of therapeutic, indicating that no matter induced them didn’t kill the animal. Similarities had been noticed between Sue’s therapeutic and the healed breaks in different fossilized bones in addition to therapeutic bone seen round holes made within the skulls of historic Inca folks in Peru.

The reason for Sue’s holes stays a puzzle.

Rothschild proposed the potential of claw injury throughout mating, or as he put it: “mounting from again or prime with claws placing the posterior mandible.” Sue has a female identify – honoring the lady who found the fossils in 1990 – however the dinosaur’s intercourse is unknown.

“I actually don’t have any clue what shaped them,” O’Connor mentioned. “I actually don’t assume they’re chew marks or claw marks.”

“A pathology that generally affected T. rex people, that induced massive holes to open up within the jawbone however solely behind the jawbone, however did not kill the T. rex as a result of the holes began to heal, no less than in Sue – it is bizarre,” O’Connor added. “So many hypotheses have been put forth solely to be shot down. It is a good paleontology thriller – my favourite.”

The holes weren’t the one examples of harm endured by Sue, a dinosaur that lived about 33 years.

“Sue was fairly outdated when it died and it exhibits quite a few accidents and pathologies,” O’Connor mentioned. “It had gout in its fingers. It had fallen on its proper aspect, busting its ribs – they healed, although. It had torn a ligament in the suitable arm – therapeutic. It had a horrible bone an infection in its left leg. It had arthritis in its tail. It will not have been a contented camper the final 12 months of its life.”

(The story refiles to repair typo in paragraph 13, ‘shot down’.)