Remains of gigantic flying reptiles found in Argentina

[rogue06]

Researchers in Argentina uncovered the remains of a pair of pterosaurs (flying reptiles) in the Andes mountains in the country's western Mendoza province that was huge. They were found in the Late Cretaceous Plottier Formation of the Neuquén Basin in fluvial or alluvial sediments dated to being 86 myo. The pterosaur has been described as a new genus of Quetzalcoatlinae [a subfamily of Azhdarchidae].

The creature was dubbed "The Dragon of Death" by the researchers, with it's official name being Thanatosdrakon amaru, with the first or genus name being a combination of two Greek words -- thantos (which means "death") and drakon (meaning "dragon"), and the second, or species name, amaru means "flying serpent" in the local Quechuan language and refers to the Incan deity Amaru.

The holotype consisted of a well-preserved in three dimensions but definitely partial postcranial skeleton consisting of several axial and appendicular bones, while not a lot contained elements that had not been described in giant azhdarchids, such as a complete notarium, dorsosacral vertebrae and caudal vertebra. It's wingspan was approximately 7 meters (23').

The second specimen, known as the paratype and was from a larger specimen, consists of a complete left humerus. Still, that's enough to determine that it's wingspan was likely 9 metres (30') long.

Not quite as big as Quetzalcoatlus itself, but still huge. In fact, Thanatosdrakon is the largest pterosaur discovered in South America, and one of the biggest flying vertebrates to have ever lived. It is also the oldest known member of the Quetzalcoatlinae.

Finally, the fact that the remains of Thanatosdrakon were found in floodplain deposits of ephemeral meandering systems strongly suggests that it inhabited continental environments, something there wasn't a lot of support for before.

Source: Giant ‘dragon of death’ with 30-foot wingspan unearthed in Argentina

Thanatosdrakon is the largest pterosaur ever found in South America.

Researchers in Argentina have unearthed the largest pterosaur species ever found in South America. Dubbed "dragon of death" by paleontologists, two giant flying reptiles were discovered in the Plottier Formation, an outcrop located in the province of Mendoza.

The two specimens' wingspans measured approximately 23 feet (7 meters) wide and 30 feet (9 m) wide, respectively. Researchers confirmed that they are azhdarchids, a family of pterosaurs that lived during the end of the Cretaceous period (approximately 146 million to 66 million years ago).

"Azhdarchids were known for their very large skulls — sometimes larger than their bodies — as well as their hyper-elongated necks and short, robust bodies," Leonardo D. Ortiz David, lead author of a new study describing the enormous pterosaurs and coordinator general of Argentina's Laboratory and Museum of Dinosaurs in Mendoza, told Live Science in an email.

The scientists identified the pterosaurs as two individuals in the species Thanatosdrakon amaru. This is the sole species in the genus, which means "dragon of death," in Greek. The species name, "amaru," translates as "flying serpent" from the Indigenous Quechuan language and refers to Amaru, a two-headed Incan deity, the study authors reported.

Researchers determined that the two pterosaurs died at the same time and that one was not yet fully grown. But the scientists can't say for sure if the two animals represent part of a family group.

"There is no indication in the fossil remains of a degree of parental relationship," Ortiz David said. "However, it can be confirmed that both specimens are of different sizes, and that the smaller one is a juvenile-subadult, and that they were together when they died more than 86 million years ago."

ZdRamHrjQyXrYKbjy6QD9B-970-80.jpg
Paleontologist Leonardo D. Ortiz David stands next to a life-size reconstruction of Thanatosdrakon at the
Laboratory and Museum of Dinosaurs at the National University of Cuyo in Mendoza, Argentina.

The fossils were found during excavations for a civil construction project about 500 miles (800 kilometers) outside Mendoza's capital city (also named Mendoza). Ortiz David and his team were supervising the dig when they discovered fossil fragments within floodplain deposits. Mendoza, where Aconcagua, the highest mountain in the Americas, is also located, is well known among paleontologists for other important dinosaur discoveries, including that of the giant sauropod Notocolossus, one of the largest dinosaurs in the world, in 2016. (Ortiz David's research group made that discovery as well.)

"The [Thanatosdrakon] fossils were in different states of preservation; some of them were complete, such as both humeri [large arm bones], syncarpals [fused foot bones] and dorsal vertebrae," he said. "Others were fragmentary, including the phalanges [toe bones], ulna, radius [forearm bones], femur [upper leg bone] and pelvis."

Ortiz David said that the team's discovery of fossils in such good condition was surprising, because pterosaur bones are fragile, and fossils are usually found in tiny pieces.

"From the beginning, two facts caught our attention: The first was the size of the remains and their preservation in three dimensions, an unusual condition in this group of vertebrates; the second was the amount of remains found at the site, since large-giant pterosaurs are only known from fragmentary remains (with some exceptions)," he said. "The description of new specimens is always important for vertebrate paleontology, as they shed light on the different groups being studied. In this particular case, 3D elements of large pterosaurs are scarce, making Thanatosdrakon an excellent case study."

The fossils are currently housed in the Laboratory and Museum of Dinosaurs at the National University of Cuyo in Mendoza. To help preserve the specimens, museum experts made casts of the different fossils on a 1-to-1 scale; the casts are on display at the museum.


Source

© Copyright Original Source

The abstract for the paper, Thanatosdrakon amaru, gen. et sp. nov., a giant azhdarchid pterosaur from the Upper Cretaceous of Argentina, can be read below:

Abstract

The largest pterosaur discovered in South America and one of the largest flying vertebrates in the world is described. Thanatosdrakon amaru gen. et sp. nov. is a new azhdarchid found in the upper-most levels of the Plottier Formation (upper Coniacian–lower Santonian, Neuquén Basin), Mendoza, Argentina. Two specimens were identified, the holotype (UNCUYO-LD 307) and the paratype, with an estimated wingspan of ∼7 m and ∼9 m, respectively. The cladistic analysis, based on 216 characters and 97 taxa, recovered Thanatosdrakon deeply nested within Azhdarchidae. Relationships within this clade are well resolved and the clade Quetzalcoatlinae presents two well-defined sister-groups: (Arambourgiania, Mistralazhdarcho, Aerotitan, Hatzegopteryx, Albadraco) + (Cryodrakon, Thanatosdrakon, Quetzalcoatlus ssp.). Thanatosdrakon is the oldest taxon of the clade Quetzalcoatlinae so far. It is represented by several well-preserved axial and appendicular bones in three dimensions. Some of these elements have never been described in giant azhdarchids (e.g. complete norarium, dorsosacral vertebrae and caudal vertebra) and this allows to expand the knowledge about the anatomy of this diverse group of pterosaurs. Finally, from a paleoecological point of view, Thanatosdrakon was found in floodplain deposits of ephemeral meandering systems indicating that this large flying species inhabited continental environments.

And, of course, pix:

Thanatosdrakon_amaru-novataxa_2022-Ortiz_David_Gonzalez_Riga_et_Kellner (1).jpg

Thanatosdrakon_amaru-novataxa_2022-Ortiz_David_Gonzalez_Riga_et_Kellner.jpg


9951fd6d-ba60-4081-af0c-7855169ece72.jpg
This graphic shows how Thanatosdrakon amaru (F) compared in size to today's Andean condor (A),
wandering albatross (B), and other pterosaurs, including the largest Quetzalcoatlus (G)

[lee_merrill]

So humans could fly if they had a 30-foot wingspan! And flight muscles to go with the wings...

Blessings,
Lee

[tabibito]

So humans could fly if they had a 30-foot wingspan! And flight muscles to go with the wings...

Blessings,
Lee

Whatever it might be, human isn't it.

[Ronson]

Something looks wonky here. These dinos apparently had skulls with large eye sockets. But in the artist recreations, the actual eyes are portrayed as small - and the ridges of the sockets (either bone or flesh) are large and obstructive to the creature's view. That doesn't make evolutionary sense.

[Ronson]

More wonkiness ...

When I Googled images of this creature, there were more inconsistencies. Two images - both from BBC articles - have distinctly different anatomies (below) and would have different diets. Quite confusing.

dino.jpg

dino2.jpg

[rogue06]

So humans could fly if they had a 30-foot wingspan! And flight muscles to go with the wings...

Blessings,
Lee

It's a bit more than that.

Two things immediately off the top of the head. Bone thickness and the furcula.

Particularly in the wings, analogous our arms, the bones were very thin walled hollow tubes. A lot like birds. This is because excess weight in any form is the bane to flight. The more there is, the more it limits your flight. Every bit that can be shed and not injure necessary functions is a bonus.

The second one you are probably familiar with from Thanksgiving time when you and someone else pulled it apart as you made a wish. Yup. The wishbone, or properly, the furcula. It forms a very important connection for many of all those muscles and tendons needed for flight.

In the time that it took to write that I thought of a number of other important changes, including lung structure which even entails air sacs in some bones.

As the early episode of South Park made comically clear as the father of one of the main characters was having surgery to become a dolphin. It doesn't work that way.

COqRV5bUwAAwSkp.jpg
He needed a walker because it was tough walking on flipper feet

[rogue06]

More wonkiness ...

When I Googled images of this creature, there were more inconsistencies. Two images - both from BBC articles - have distinctly different anatomies (below) and would have different diets. Quite confusing.

dino.jpg

dino2.jpg

If those represent artist recreations of Thanatosdrakon the fact that no cranial material -- the skull, mandible (lower jaw) or even teeth -- were recovered allows for a heck of a lot of artistic license.

What should be kept in mind is that this pterosaur's prey was from in and around rivers and streams in inland flood plains and not like all the others which apparently were costal creatures. The differences in diet should be reflected in the structure of every part of cranial material.

[Ronson]

If those represent artist recreations of Thanatosdrakon the fact that no cranial material -- the skull, mandible (lower jaw) or even teeth -- were recovered allows for a heck of a lot of artistic license.

What should be kept in mind is that this pterosaur's prey was from in and around rivers and streams in flood plains and not like all the others which apparently were costal creatures. The differences in diet should be reflected in the structure of every part of cranial material.

I don't know how much material has been recovered. I was just surprised that one article showed the creature with teeth and the other article didn't.

But the eyes are the biggest problem, IMO, and all the recreations are the same. Why do they suppose a creature like this would have relatively small eyes? And that they were positioned in such a way to make three-dimensional hunting nearly impossible? Large eye sockets = large eyes. And large eyes would be able to see beyond the socket ridges so it could zero in on prey, or even on a piece of hanging fruit (whatever it ate).

The top pic with teeth is the most illogical.

[rogue06]

I don't know how much material has been recovered.

From the OP:

Thanatosdrakon_amaru-novataxa_2022-Ortiz_David_Gonzalez_Riga_et_Kellner.jpg

Even though not a lot was recovered (enough to determine it was a previously unknown species and genus as well), it is from previously known groups of pterosaurs meaning that it is extremely likely that they got the basic structure correct.

I was just surprised that one article showed the creature with teeth and the other article didn't.

Word of warning. I've used Google images to find pictures of things like this quite frequently and have discovered it necessary to be extremely careful about selecting them. Often the pictures are not a representation of the creature itself, but of a previously known relative. They don't always even make that clear and when they do it's usually in the picture credits in the article.

But the eyes are the biggest problem, IMO, and all the recreations are the same. Why do they suppose a creature like this would have relatively small eyes? And that they were positioned in such a way to make three-dimensional hunting nearly impossible? Large eye sockets = large eyes. And large eyes would be able to see beyond the socket ridges so it could zero in on prey, or even on a piece of hanging fruit (whatever it ate).

The top pic with teeth is the most illogical.

Tbh, I don't have an answer, although I suspect that just like birds and pterosaurs evolved with thin-walled bones to reduce weight, that these spaces may have expanded for the same reason. That would make sense given that pterosaurs, and IIRC, particularly this family of them, are known for having huge heads. Losing unnecessary skull material would make sense.

Keep in mind, birds are thought to have lost their teeth in order to reduce weight, so this is hardly far-fetched.

Still, some pterosaurs had teeth. I own several long thin needle-like pterosaur teeth. They were designed for catching fish.

ETA: Forgot to note that some pterosaurs were nocturnal and would have possedssed large eyes.

[Ronson]

From the OP:

Even though not a lot was recovered (enough to determine it was a previously unknown species and genus as well), it is from previously known groups of pterosaurs meaning that it is extremely likely that they got the basic structure correct.

Word of warning. I've used Google images to find pictures of things like this quite frequently and have discovered it necessary to be extremely careful about selecting them. Often the pictures are not a representation of the creature itself, but of a previously known relative. They don't always even make that clear and when they do it's usually in the picture credits in the article.

Tbh, I don't have an answer, although I suspect that just like birds and pterosaurs evolved with thin-walled bones to reduce weight, that these spaces may have expanded for the same reason. That would make sense given that pterosaurs, and IIRC, particularly this family of them, are known for having huge heads. Losing unnecessary skull material would make sense.

Keep in mind, birds are thought to have lost their teeth in order to reduce weight, so this is hardly far-fetched.

Still, some pterosaurs had teeth. I own several long thin needle-like pterosaur teeth. They were designed for catching fish.

ETA: Forgot to note that some pterosaurs were nocturnal and would have possedssed large eyes.

Here's my rendition on the eyes:

dino3.jpg

I would think that would be a bit closer. And if it was a predator, they would be set more forward facing.

Maybe some more fossils will show up soon.

[rogue06]

Here's my rendition on the eyes:

dino3.jpg

I would think that would be a bit closer. And if it was a predator, they would be set more forward facing.

Maybe some more fossils will show up soon.

FWIU, they had binocular vision.

[NorrinRadd]

FWIU, they had binocular vision.

Which, IIRC, is relatively more common in predators, and would not be possible with those side-mounted orbs (except in weird cases like chameleons).

[rogue06]

Which, IIRC, is relatively more common in predators, and would not be possible with those side-mounted orbs (except in weird cases like chameleons).

Um, there are carnivorous dinosaurs -- and crocodiles as well -- that had/have laterally placed eyes.

[NorrinRadd]

Um, there are carnivorous dinosaurs -- and crocodiles as well -- that had/have laterally placed eyes.

But the binocular vision part wouldn't be possible.

[rogue06]

But the binocular vision part wouldn't be possible.

Their depth perception is/was limited.

Do you remember the scene in the original Jurassic Park where the scientist tells everyone to stand perfectly still so the T rex wouldn't see them? Bad advice that was apparently based on older information about the T-rex's vision. They were one that did have binocular vision -- although not as good as a Velociraptor -- and he would have seen you just fine.