Qunkasaura: New sauropod dinosaur from the Cretaceous discovered in the Iberian Peninsula
image:
General view of the Lo Hueco site during the excavation of Qunkasaura in 2007
view moreCredit: GBE-UNED
A new study led by Portuguese paleontologist Pedro Mocho, from the Instituto Dom Luiz of the Faculty of Sciences of the University of Lisbon (CIÊNCIAS), has just been published in the Communications Biology journal, which announces a new species of sauropod dinosaur that lived in Cuenca, Spain, 75 million years ago: Qunkasaura pintiquiniestra.
The more than 12,000 fossils collected from 2007 onwards during works to install the Madrid-Levante high-speed train (AVE) tracks revealed this deposit, giving rise to one of the most relevant collections of fossil vertebrates from the Upper Cretaceous of Europe. The collection has been studied continuously thanks to national projects and the Junta de Comunidades de Castilla-La Mancha, which has made it possible to significantly increase the understanding of the ecosystems of southwestern Europe during the Late Cretaceous and also identify several new species for science.
“The study of this specimen allowed us to identify for the first time the presence of two distinct lineages of saltasauroids in the same fossil locality. One of these groups, called Lirainosaurinae, is relatively known in the Iberian region and is characterized by small and medium-sized species, which evolved in an island ecosystem. In other words, Europe was a huge archipelago made up of several islands during the Late Cretaceous. However, Qunkasaura belongs to another group of sauropods, represented in the Iberian Peninsula by medium-large species 73 million years ago. This suggests to us that this lineage arrived in the Iberian Peninsula much later than other groups of dinosaurs”, explains Pedro Mocho, paleontologist at CIÊNCIAS.
One of the most relevant features of the Lo Hueco fossil record is the abundance of large partial skeletons of sauropod dinosaurs, which are rare in the rest of Europe. Qunkasaura pintiquiniestra stands out for being one of the most complete sauropod skeletons found in Europe, including cervical, dorsal and caudal vertebrae, part of the pelvic girdle and elements of the limbs. Their unique morphology, especially in the tail vertebrae, offers new insights into the non-avian dinosaurs of the Iberian Peninsula, a historically poorly understood group.
The study, now published in the Communications Biology journal, identifies Qunkasaura as a representative of the opisthocoelicaudine saltasaurids, a group present in the northern hemisphere (Laurasia). On the other hand, most Late Cretaceous sauropods from southwestern Europe, including Lohuecotitan pandafilandi, previously described from Lo Hueco, belong to the group Lirainosaurinae, a group of sauropods apparently exclusive to the European continent. This study suggests that Lo Hueco is the only place where the coexistence of both groups is known and proposes a new group of titanosaurs called Lohuecosauria, which includes representatives of both lineages. Lohuecosaurs may have originated on the southern continents (Gondwana) before dispersing globally.
The name Qunkasaura pintiquiniestra is made up of several geographic and cultural references close to the Lo Hueco site. "Qunka" refers to the oldest etymology of the toponym from the Cuenca and Fuentes area, "Saura" alludes to the feminine of the Latin saurus (lizard), but also pays homage to the painter Antonio Saura, and "pintiquiniestra" refers to the giant "Queen Pintiquiniestra", character from a novel mentioned in ‘Don Quijote de la Mancha’ by Cervantes.
“Fortunately, the Lo Hueco deposit also preserves several skeletons of sauropod dinosaurs to be determined, which may correspond to new species and which will help us understand how these animals evolved”, concludes Pedro Mocho.
The study is part of the research conducted by the Evolutionary Biology Group at UNED on ecosystems with dinosaurs in central Iberian Peninsula. Part of the skeleton of Qunkasaura is already on display in the Paleontological Museum of Castilla-La Mancha in Cuenca (Spain).
Reference:
Mocho, P.; Escaso, F.; Marcos-Fernández, F.; Páramo, A.; Sanz, J. L.; Vidal, D.; Ortega, F. 2024. A Spanish saltasauroid titanosaur reveals Europe as a melting pot of endemic and immigrant sauropods in the Late Cretaceous. Communications Biology. DOI: https://doi.org/10.1038/s42003-024-06653-0
Restoration process of part of the remains of Qunkasaura.
Credit
GBE-UNED
Reconstruction of the life form of Qunkasaura pintiquiniestra.
Credit
José Antonio Peñas Artero
3D reconstruction of the Qunkasaura skeleton.
Credit
GBE-UNED
Relationships of Qunkasaura with some of the most important sauropods from the Late Cretaceous and reconstruction of the life form of Qunkasaura pintiquiniestra.
Credit
José Antonio Peñas Artero, GBE-UNED, FCUL
Bone remains of Qunkasaura pintiquiniestra, on display in the Paleontological Museum of Castilla-La Mancha.
Credit
GBE-UNED
Journal
Communications Biology
Article Title
A Spanish saltasauroid titanosaur reveals Europe as a melting pot of endemic and immigrant sauropods in the Late Cretaceous
Article Publication Date
4-Sep-2024
Why dinosaur collagen might have staying power
Dinosaurs continue to fascinate people, but that’s not their only enduring quality: Collagen in their skeletons remains intact for millions of years, despite containing chemical bonds that should only persist for about 500 years. Now, scientists report in ACS Central Science that the unique tenacity of this protein may result from a molecular structure that shields these vulnerable bonds from attack by water that’s present in the environment.
Collagen is the most abundant protein in animals. It’s found in skin and connective tissues, such as cartilage and bones. Fragments of collagen have been extracted from the bones of 68-million-year-old fossils of Tyrannosaurus rex and may have even been detected in the skeleton of a 195-million-year-old Lufengosaurus. Collagen consists of protein strands — chains of amino acids — that form triple helices. Much like a rope, the helices in turn weave together to form a strong fibrous material. When exposed to water, the peptide bonds that connect amino acids normally break down in a process known as hydrolysis. But when peptides are incorporated in collagen, that destructive process doesn’t take place. Various explanations have been proposed, but Ron Raines and colleagues felt those theories were missing a physical and chemical basis for the resistance of peptide bonds in collagen like that preserved in ancient dinosaur bones. The team set out to fill in the missing links.
Using experimental and computational methods, the researchers examined the behavior of small-molecule mimics of collagen peptides. In particular, they studied the interactions between the molecules’ acyl groups, which each contain a carbon atom double bonded to an oxygen atom. They found that each acyl group partially shares its electrons with a neighboring acyl group. These results suggest that such interactions protect every peptide bond in a collagen triple helix from hydrolysis, and therefore the structure is able to stay intact. The researchers say lessons from the stability conferred by these interactions could help guide the design of other exceptionally long-lived materials.
The authors acknowledge funding from the National Institutes of Health.
The paper’s abstract will be available on Sept. 4 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acscentsci.4c00971
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Journal
ACS Central Science
Article Title
Pauli Exclusion by n→π* Interactions: Implications for Paleobiology
Article Publication Date
4-Sep-2024
MIT chemists explain why dinosaur collagen may have survived for millions of years
The researchers identified an atomic-level interaction that prevents peptide bonds from being broken down by water
Massachusetts Institute of Technology
Collagen, a protein found in bones and connective tissue, has been found in dinosaur fossils as old as 195 million years. That far exceeds the normal half-life of the peptide bonds that hold proteins together, which is about 500 years.
A new study from MIT offers an explanation for how collagen can survive for so much longer than expected. The research team found that a special atomic-level interaction defends collagen from attack by water molecules. This barricade prevents water from breaking the peptide bonds through a process called hydrolysis.
“We provide evidence that that interaction prevents water from attacking the peptide bonds and cleaving them. That just flies in the face of what happens with a normal peptide bond, which has a half-life of only 500 years,” says Ron Raines, the Firmenich Professor of Chemistry at MIT.
Raines is the senior author of the new study, which will appear in ACS Central Science. MIT postdoc Jinyi Yang PhD ’24 is the lead author of the paper. MIT postdoc Volga Kojasoy and graduate student Gerard Porter are also authors of the study.
Water-resistant
Collagen is the most abundant protein in animals, and it is found in not only bones but also skin, muscles, and ligaments. It’s made from long strands of protein that intertwine to form a tough triple helix.
“Collagen is the scaffold that holds us together,” Raines says. “What makes the collagen protein so stable, and such a good choice for this scaffold, is that unlike most proteins, it’s fibrous.”
In the past decade, paleobiologists have found evidence of collagen preserved in dinosaur fossils, including an 80-million-year-old Tyrannosaurus rex fossil, and a sauropodomorph fossil that is nearly 200 million years old.
Over the past 25 years, Raines’ lab has been studying collagen and how its structure enables its function. In the new study, they revealed why the peptide bonds that hold collagen together are so resistant to being broken down by water.
Peptide bonds are formed between a carbon atom from one amino acid and a nitrogen atom of the adjacent amino acid. The carbon atom also forms a double bond with an oxygen atom, forming a molecular structure called a carbonyl group. This carbonyl oxygen has a pair of electrons that don’t form bonds with any other atoms. Those electrons, the researchers found, can be shared with the carbonyl group of a neighboring peptide bond.
Because this pair of electrons is being inserted into those peptide bonds, water molecules can’t also get into the structure to disrupt the bond.
To demonstrate this, Raines and his colleagues created two interconverting mimics of collagen — the one that usually forms a triple helix, which is known as trans, and another in which the angles of the peptide bonds are rotated into a different form, known as cis. They found that the trans form of collagen did not allow water to attack and hydrolyze the bond. In the cis form, water got in and the bonds were broken.
“A peptide bond is either cis or trans, and we can change the cis to trans ratio. By doing that, we can mimic the natural state of collagen or create an unprotected peptide bond. And we saw that when it was unprotected, it was not long for the world,” Raines says.
“No weak link”
This sharing of electrons has also been seen in protein structures known as alpha helices, which are found in many proteins. These helices may also be protected from water, but the helices are always connected by protein sequences that are more exposed, which are still susceptible to hydrolysis.
“Collagen is all triple helices, from one end to the other,” Raines says. “There’s no weak link, and that’s why I think it has survived.”
Previously, some scientists have suggested other explanations for why collagen might be preserved for millions of years, including the possibility that the bones were so dehydrated that no water could reach the peptide bonds.
“I can’t discount the contributions from other factors, but 200 million years is a long time, and I think you need something at the molecular level, at the atomic level in order to explain it,” Raines says.
The research was funded by the National Institutes of Health and the National Science Foundation.
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Written by Anne Trafton, MIT News
Paper: “Pauli Exclusion by n→π* Interactions: Implications for Paleobiology”
Journal
ACS Central Science
Article Title
Pauli Exclusion by n→π* Interactions: Implications for Paleobiology
Article Publication Date
4-Sep-2024
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