Pregnant T-Rex found that lived 68 million years ago

Pregnant T-Rex found that lived 68 million years ago

Scientists found a pregnant T-Rex (Tyrannosaurus rex), and this can help with the study of the evolution of egg-laying as well as on gender differences in the dinosaur.

The remains could also contain the DNA of all dinosaur fossils. The fossil was discovered long back in 2005, but just now, experts came to know that the T.Rex was a mother-to-be when it took its last breath.
This new finding is expected to be a breakthrough in the field of paleontology as most of the times; experts fail to determine the exact gender of dinosaurs.

The team from North Carolina State University and the North Carolina Museum of Natural Sciences published its findings Tuesday in the journal Scientific Reports.

Researchers have found the medullary bone in the femur of the fossil, and it helped them to make a conclusion that the T-Rex is pregnant. Medullary bone is only present in female birds — which are related to dinosaurs — just before and during egg-laying.

“It’s a special tissue that is built up as easily mobilised calcium storage just before egg-laying,”.

“The outcome is that birds do not have to pull calcium from the main part of their bones in order to shell eggs, weakening their bones the way crocodiles do.”

Crocodiles are the closest-living relatives of dinosaurs.

“Medullary bone is thus present just before and during egg-laying, but is entirely gone after the female has finished laying eggs,”Dr Lindsay Zanno, the assistant research professor of biological sciences at North Carolina State University, said.

Cross-section-of-T-rex-bone

Cross section of T-Rex bone

“We have some evidence that fragments of DNA may be preserved in dinosaur fossils, but this remains to be tested further.” said Dr. Zanno.

Yi Qi… a bird, or a bat?

Yi Qi… a bird, or a bat?

Yi is a genus of scansoriopterygid (meaning “climbing wings”) dinosaurs from the Late Jurassic of China.

Scansoriopterygids are small maniraptoran theropods, notable for their elongate third fingers and for a peculiar pelvis where the pubis is directed forwards and downwards, is proportionally short and lacks an expanded ventral end. The scansoriopterygid skull is short-faced and robust, the anterior end of the lower jaw is slightly downturned, and the teeth are procumbent.

Yi Qi (meaning “Strange Wings”) species is known from a single fossil specimen of an adult individual found in Middle or Late Jurassic of Hebei, China, approximately 160 million years ago.
It is preserved with a full coating of feathers and was a close relative of the lineage that ultimately gave rise to birds. The fossil was compressed and is visible on a stone plate and a counterplate. It is largely articulated, including the skull, lower jaws, neck and limb bones but lacking most of the backbone, pelvis and tail. Yi was a relatively small animal, estimated to weigh about 380 grams.

Like all maniraptorans, scansoriopterygids are fully feathered, but it seems that they don’t possess vaned, pennaceous feathers like those present in oviraptorosaurs, birds, dromaeosaurids and so on. Instead, they have filamentous, branching, brush-like structures of various sorts. And Yi Qi is another Mesozoic fossil dinosaur that seemingly preserves melanosomes in its integumentary structures.
Small patches of wrinkled skin were also preserved, between the fingers and the styliform bone, indicating that unlike all other known dinosaurs, the planes of Yi qi were formed by a skin membrane rather than flight feathers. On twelve positions the fossil was checked by an electron microscope for the presence of melanosomes, pigment-bearing organelles. All nine feather locations showed eumelanosomes, which cause a black colour. In the head feathers also phaeomelanosomes were present, rendering a more yellow-brownish hue. On the membranes, only one observation had a positive result, of phaeomelanosomes. The eumelanosomes of the calf feathers were exceptionally large.

Professor Xu Xing, lead author of the study from the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing said “It definitely evolved a wing that is unique in the context of the transition from dinosaurs to birds.”

YiQi skeletal drawing

YiQi skeletal drawing

Dreadnoughtus, the gigantic sauropod dinosaur

Dreadnoughtus, the gigantic sauropod dinosaur

Dreadnoughtus is a genus of giant titanosaurian sauropod dinosaur from the Upper Cretaceous, discovered in the (Campanian-Maastrichtian; 84–66 Ma) Cerro Fortaleza Formation of Santa Cruz province, Argentina. It is one of the largest of all known terrestrial vertebrates, possessing the greatest mass of any land animal that can be calculated with reasonable certainty, using limb bone measurements. In terms of skeletal completeness and ability to encode its anatomy into cladistic analyses, Dreadnoughtus schrani is the most complete gigantic titanosaurian sauropod dinosaur (Wikipedia).
They named the dinosaur “Dreadnoughtus”, which translates to “fears nothing.”

Last year, scientists have discovered this supermassive dinosaur species with the most complete skeleton ever found of its type, and it might be the world’s largest terrestrial animal, as you can see his size in the pictures hreunder:

Dreadnoughtus size

Dreadnoughtus- size

With a height of 85 feet,  and weighing about 65 tons which is equal to 59,300 Kg!!
Professor Kenneth Lacovara, an associate professor in Drexel University’s College of Arts and Sciences, who discovered the Dreadnoughtus fossil skeleton in southern Patagonia in Argentina and led the excavation and analysis. “It weighed as much as a dozen African elephants or more than seven T. rex. Shockingly, skeletal evidence shows that when this 65-ton specimen died, it was not yet full grown. It is by far the best example we have of any of the most giant creatures to ever walk the planet.”

To better visualize the skeletal structure of Dreadnoughtus, Lacovara’s team digitally scanned all of the bones from both dinosaur specimens. They have made a “virtual mount” of the skeleton that is now publicly available for download from the paper’s open-access online supplement as a three-dimensional digital reconstruction.

 

Dinosaur ‘Romeo and Juliet’ Found Buried Together

Dinosaur ‘Romeo and Juliet’ Found Buried Together

A dinosaur couple that appears to have died together after wooing each other has been identified in remains unearthed at the Gobi Desert in Mongolia.

The dino couple, named Romeo and Juliet since they are reminiscent of Shakespeare’s famous doomed lovers, were entombed together for over 75 million years, according to a new study in the journal Scientific Reports.

Key to the research was figuring out the sex of the dinosaurs.

“Determining a dinosaur’s gender is really hard,” lead author Scott Persons said in a press release. “Because soft anatomy seldom fossilizes, a dinosaur fossil usually provides no direct evidence of whether it was a male or a female.”

Persons, a paleontologist at the University of Alberta, and his team compared the remains of the bird-like dinosaurs, which were oviraptors (avian-resembling two-legged predators), with the anatomy of modern birds.

The researchers found evidence that the dinosaurs sported long feathers on the ends of their tails. The feathers were not suitable for flight, so they must have served some other purpose.

“Our theory,” explained Persons, “was that these large feather-fans were used for the same purpose as the feather fans of many modern ground birds, like turkeys, peacocks, and prairie chickens: they were used to enhance courtship displays. My analysis of the tail skeletons supported this theory, because the skeletons showed adaptations for both high tail flexibility and enlarged tail musculature — both traits that would have helped an oviraptor to flaunt its tail fan in a mating dance.”

Taking their analysis a step further, the research team discovered that one of the two dinosaurs had larger, specially shaped tailbones. The differences were expected, and match that of some male versus female birds today. They provide strong evidence for sexual dimorphism, meaning distinct differences in the size or appearance between the sexes of an animal.

“We discovered that, although both oviraptors were roughly the same size, the same age, and otherwise identical in all anatomical regards, ‘Romeo’ had larger and specially shaped tail bones,” said Persons. “This indicates that it had a greater capacity for courtship displays and was likely a male.”

“Juliet,” other other hand, had tail bones that were shorter and simpler, suggesting a lesser capacity for “peacocking,” meaning prancing around like a male peacock to flaunt one’s feathers. Juliet was then a “she,” according to the researchers.

As for what happened to the pair in the desert…after whatever romance may have transpired, a large sand dune suddenly collapsed on top of them, preserving the pair for near-perpetuity.

Image: Illustration of the oviraptors Romeo and Juliet, Credit: Scott Persons, University of Alberta

Source: Discover News