What Happened to Dinosaurs’ Predecessors After Earth’s Largest Extinction 252 Million Years Ago?
Predecessors to dinosaurs missed the race to fill habitats emptied when nine out of 10 species disappeared during Earth’s largest mass extinction 252 million years ago.
Or did they?
That thinking was based on fossil records from sites in South Africa and southwest Russia.
It turns out, however, that scientists may have been looking in the wrong places.
Newly discovered fossils from 10 million years after the mass extinction reveal a lineage of animals thought to have led to dinosaurs in Tanzania and Zambia.
That’s still millions of years before dinosaur relatives were seen in the fossil record elsewhere on Earth.
“The fossil record from the Karoo of South Africa, for example, is a good representation of four-legged land animals across southern Pangea before the extinction,” says Christian Sidor, a paleontologist at the University of Washington.
Pangea was a landmass in which all the world’s continents were once joined together. Southern Pangea was made up of what is today Africa, South America, Antarctica, Australia and India.
“After the extinction,” says Sidor, “animals weren’t as uniformly and widely distributed as before. We had to go looking in some fairly unorthodox places.”
Sidor is the lead author of a paper reporting the findings; it appears in this week’s issue of the journal Proceedings of the National Academy of Sciences.
The insights come from seven fossil-hunting expeditions in Tanzania, Zambia and Antarctica funded by the National Science Foundation (NSF). Additional work involved combing through existing fossil collections.
“These scientists have identified an outcome of mass extinctions–that species ecologically marginalized before the extinction may be ‘freed up’ to experience evolutionary bursts then dominate after the extinction,” says H. Richard Lane, program director in NSF’s Division of Earth Sciences.
The researchers created two “snapshots” of four-legged animals about five million years before, and again about 10 million years after, the extinction 252 million years ago.
Prior to the extinction, for example, the pig-sized Dicynodon–said to resemble a fat lizard with a short tail and turtle’s head–was a dominant plant-eating species across southern Pangea.
After the mass extinction, Dicynodon disappeared. Related species were so greatly decreased in number that newly emerging herbivores could then compete with them.
“Groups that did well before the extinction didn’t necessarily do well afterward,” Sidor says.
The snapshot of life 10 million years after the extinction reveals that, among other things, archosaurs roamed in Tanzanian and Zambian basins, but weren’t distributed across southern Pangea as had been the pattern for four-legged animals before the extinction.
Archosaurs, whose living relatives are birds and crocodilians, are of interest to scientists because it’s thought that they led to animals like Asilisaurus, a dinosaur-like animal, and Nyasasaurus parringtoni, a dog-sized creature with a five-foot-long tail that could be the earliest dinosaur.
“Early archosaurs being found mainly in Tanzania is an example of how fragmented animal communities became after the extinction,” Sidor says.
A new framework for analyzing biogeographic patterns from species distributions, developed by paper co-author Daril Vilhena of University of Washington, provided a way to discern the complex recovery.
It revealed that before the extinction, 35 percent of four-legged species were found in two or more of the five areas studied.
Some species’ ranges stretched 1,600 miles (2,600 kilometers), encompassing the Tanzanian and South African basins.
Ten million years after the extinction, there was clear geographic clustering. Just seven percent of species were found in two or more regions.
The technique–a new way to statistically consider how connected or isolated species are from each other–could be useful to other paleontologists and to modern-day biogeographers, Sidor says.
Beginning in the early 2000s, he and his co-authors conducted expeditions to collect fossils from sites in Tanzania that hadn’t been visited since the 1960s, and in Zambia where there had been little work since the 1980s.
Two expeditions to Antarctica provided additional finds, as did efforts to look at museum fossils that had not been fully documented or named.
The fossils turned out to hold a treasure trove of information, the scientists say, on life some 250 million years ago.
Other co-authors of the paper are Adam Huttenlocker, Brandon Peecook, Sterling Nesbitt and Linda Tsuji from University of Washington; Kenneth Angielczyk of the Field Museum of Natural History in Chicago; Roger Smith of the Iziko South African Museum in Cape Town; and Sébastien Steyer from the National Museum of Natural History in Paris.
The project was also funded by the National Geographic Society, Evolving Earth Foundation, the Grainger Foundation, the Field Museum/IDP Inc. African Partners Program, and the National Research Council of South Africa.
Fish Was On the Menu for Early Flying Dinosaur
Apr. 22, 2013 — University of Alberta-led research reveals that Microraptor, a small flying dinosaur was a complete hunter, able to swoop down and pickup fish as well as its previously known prey of birds and tree dwelling mammals.
U of A paleontology graduate student Scott Persons says new evidence of Microrpator’s hunting ability came from fossilized remains in China. “We were very fortunate that this Microraptor was found in volcanic ash and its stomach content of fish was easily identified.”
Prior to this, paleontologists believed microraptors which were about the size of a modern day hawk, lived in trees where they preyed exclusively on small birds and mammals about the size of squirrels.
“Now we know that Microraptor operated in varied terrain and had a varied diet,” said Persons. “It took advantage of a variety of prey in the wet, forested environment that was China during the early Cretaceous period, 120 million years ago.”
Further analysis of the fossil revealed that its teeth were adapted to catching slippery, wiggling prey like fish. Dinosaur researchers have established that most meat eaters had teeth with serrations on both sides which like a steak knife helped the predator saw through meat.
But the Microraptor’s teeth are serrated on just one side and its teeth are angled forwards.
“Microraptor seems adapted to impale fish on its teeth. With reduced serrations the prey wouldn’t tear itself apart while it struggled,” said Persons. “Microraptor could simply raise its head back, the fish would slip off the teeth and be swallowed whole, no fuss no muss.”
Persons likens the Microraptor’s wing configuration to a bi-plane. “It had long feathers on its forearms, hind legs and tail,” said Persons. “It was capable of short, controlled flights.”
This is the first evidence of a flying raptor, a member of the Dromaeosaur family of dinosaurs to successfully prey on fish.
Dinosaur Egg Study Supports Evolutionary Link Between Birds and Dinosaurs: How Troodon Likely Hatched Its Young
A small, bird-like North American dinosaur incubated its eggs in a similar way to brooding birds — bolstering the evolutionary link between birds and dinosaurs, researchers at the University of Calgary and Montana State University study have found.
Among the many mysteries paleontologists have tried to uncover is how dinosaurs hatched their young. Was it in eggs completely buried in nest materials, like crocodiles? Or was it in eggs in open or non-covered nests, like brooding birds?
Using egg clutches found in Alberta and Montana, researchers Darla Zelenitsky at the University of Calgary and David Varricchio at Montana State University closely examined the shells of fossil eggs from a small meat-eating dinosaur called Troodon.
In a finding published in the spring issue of Paleobiology, they concluded that this specific dinosaur species, which was known to lay its eggs almost vertically, would have only buried the egg bottoms in mud.
“Based on our calculations, the eggshells of Troodon were very similar to those of brooding birds, which tells us that this dinosaur did not completely bury its eggs in nesting materials like crocodiles do,” says study co-author Zelenitsky, assistant professor of geoscience.
“Both the eggs and the surrounding sediments indicate only partial burial; thus an adult would have directly contacted the exposed parts of the eggs during incubation,” says lead author Varricchio, associate professor of paleontology.
Varricchio says while the nesting style for Troodon is unusual, “there are similarities with a peculiar nester among birds called the Egyptian Plover that broods its eggs while they’re partially buried in sandy substrate of the nest.”
Paleontologists have always struggled to answer the question of how dinosaurs incubated their eggs, because of the scarcity of evidence for incubation behaviours.
As dinosaurs’ closest living relatives, crocodiles and birds offer some insights.
Scientists know that crocodiles and birds that completely bury their eggs for hatching have eggs with many pores or holes in the eggshell, to allow for respiration.
This is unlike brooding birds which don’t bury their eggs; consequently, their eggs have far fewer pores.
The researchers counted and measured the pores in the shells of Troodon eggs to assess how water vapour would have been conducted through the shell compared with eggs from contemporary crocodiles, mound-nesting birds and brooding birds.
They are optimistic their methods can be applied to other dinosaur species’ fossil eggs to show how they may have been incubated.
“For now, this particular study helps substantiate that some bird-like nesting behaviors evolved in meat-eating dinosaurs prior to the origin of birds. It also adds to the growing body of evidence that shows a close evolutionary relationship between birds and dinosaurs,” Zelenitsky says.
New Carnivorous Dinosaur from Madagascar Raises More Questions Than It Answers
The first new species of dinosaur from Madagascar in nearly a decade was announced today, filling an important gap in the island’s fossil record.
Dahalokely tokana (pronounced “dah-HAH-loo-KAY-lee too-KAH-nah”) is estimated to have been between nine and 14 feet long, and it lived around 90 million years ago. Dahalokely belongs to a group called abelisauroids, carnivorous dinosaurs common to the southern continents. Up to this point, no dinosaur remains from between 165 and 70 million years ago could be identified to the species level in Madagascar-a 95 million year gap in the fossil record. Dahalokely shortens this gap by 20 million years.
The fossils of Dahalokely were excavated in 2007 and 2010, near the city of Antsiranana (Diego-Suarez) in northernmost Madagascar. Bones recovered included vertebrae and ribs. Because this area of the skeleton is so distinct in some dinosaurs, the research team was able to definitively identify the specimen as a new species. Several unique features — including the shape of some cavities on the side of the vertebrae — were unlike those in any other dinosaur. Other features in the vertebrae identified Dahalokely as an abelisauroid dinosaur.
When Dahalokely was alive, Madagascar was connected to India, and the two landmasses were isolated in the middle of the Indian Ocean. Geological evidence indicates that India and Madagascar separated around 88 million years ago, just after Dahalokely lived. Thus, Dahalokely potentially could have been ancestral to animals that lived later in both Madagascar and India. However, not quite enough of Dahalokely is yet known to resolve this issue. The bones known so far preserve an intriguing mix of features found in dinosaurs from both Madagascar and India.
“We had always suspected that abelisauroids were in Madagascar 90 million years ago, because they were also found in younger rocks on the island. Dahalokely nicely confirms this hypothesis,” said project leader Andrew Farke, Augustyn Family Curator of Paleontology at the Raymond M. Alf Museum of Paleontology. Farke continued, “But, the fossils of Dahalokely are tantalizingly incomplete — there is so much more we want to know. Was Dahalokely closely related to later abelisauroids on Madagascar, or did it die out without descendents?”
The name “Dahalokely tokana” is from the Malagasy language, meaning “lonely small bandit.” This refers to the presumed carnivorous diet of the animal, as well as to the fact that it lived at a time when the landmasses of India and Madagascar together were isolated from the rest of the world.
“This dinosaur was closely related to other famous dinosaurs from the southern continents, like the horned Carnotaurus from Argentina and Majungasaurus, also from Madagascar,” said project member Joe Sertich, Curator of Dinosaurs at the Denver Museum of Nature & Science and the team member who discovered the new dinosaur. “This just reinforces the importance of exploring new areas around the world where undiscovered dinosaur species are still waiting,” added Sertich.
The research was funded by the Jurassic Foundation, Sigma Xi, National Science Foundation, and the Raymond M. Alf Museum of Paleontology. The paper naming Dahalokely appears in the April 18, 2013, release of the journal PLOS ONE.
World’s Oldest Dinosaur Embryo Bonebed Yields Organic Remains
Apr. 10, 2013 — The great age of the embryos is unusual because almost all known dinosaur embryos are from the Cretaceous Period. The Cretaceous ended some 125 million years after the bones at the Lufeng site were buried and fossilized.
Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People’s Republic of China, Australia, and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.
“We are opening a new window into the lives of dinosaurs,” says Reisz. “This is the first time we’ve been able to track the growth of embryonic dinosaurs as they developed. Our findings will have a major impact on our understanding of the biology of these animals.”
The bones represent about 20 embryonic individuals of the long-necked sauropodomorph Lufengosaurus, the most common dinosaur in the region during the Early Jurassic period. An adult Lufengosaurus was approximately eight metres long.
The disarticulated bones probably came from several nests containing dinosaurs at various embryonic stages, giving Reisz’s team the rare opportunity to study ongoing growth patterns. Dinosaur embryos are more commonly found in single nests or partial nests, which offer only a snapshot of one developmental stage.
To investigate the dinosaurs’ development, the team concentrated on the largest embryonic bone, the femur. This bone showed a consistently rapid growth rate, doubling in length from 12 to 24 mm as the dinosaurs grew inside their eggs. Reisz says this very fast growth may indicate that sauropodomorphs like Lufengosaurus had a short incubation period.
Reisz’s team found the femurs were being reshaped even as they were in the egg. Examination of the bones’ anatomy and internal structure showed that as they contracted and pulled on the hard bone tissue, the dinosaurs’ muscles played an active role in changing the shape of the developing femur. “This suggests that dinosaurs, like modern birds, moved around inside their eggs,” says Reisz. “It represents the first evidence of such movement in a dinosaur.”
The Taiwanese members of the team also discovered organic material inside the embryonic bones. Using precisely targeted infrared spectroscopy, they conducted chemical analyses of the dinosaur bone and found evidence of what Reisz says may be collagen fibres. Collagen is a protein characteristically found in bone.
“The bones of ancient animals are transformed to rock during the fossilization process,” says Reisz. “To find remnants of proteins in the embryos is really remarkable, particularly since these specimens are over 100 million years older than other fossils containing similar organic material.”
Only about one square metre of the bonebed has been excavated to date, but this small area also yielded pieces of eggshell, the oldest known for any terrestrial vertebrate. Reisz says this is the first time that even fragments of such delicate dinosaur eggshells, less than 100 microns thick, have been found in good condition.
“A find such as the Lufeng bonebed is extraordinarily rare in the fossil record, and is valuable for both its great age and the opportunity it offers to study dinosaur embryology,” says Reisz. “It greatly enhances our knowledge of how these remarkable animals from the beginning of the Age of Dinosaurs grew.”
New Evidence Dinosaurs Were Strong Swimmers
Apr. 8, 2013 — A University of Alberta researcher has identified some of the strongest evidence ever found that dinosaurs could paddle long distances.
Working together with an international research team, U of A graduate student Scott Persons examined unusual claw marks left on a river bottom in China that is known to have been a major travel-way for dinosaurs.
Alongside easily identified fossilized footprints of many Cretaceous era animals including giant long neck dinosaur’s researchers found a series of claw marks that Persons says indicates a coordinated, left-right, left-right progression.
“What we have are scratches left by the tips of a two-legged dinosaur’s feet,” said Persons. “The dinosaur’s claw marks show it was swimming along in this river and just its tippy toes were touching bottom.”
The claw marks cover a distance of 15 meters which the researchers say is evidence of a dinosaur’s ability to swim with coordinated leg movements. The tracks were made by carnivorous theropod dinosaur that is estimated to have stood roughly 1 meter at the hip.
Fossilized rippling and evidence of mud cracks indicate that over 100 million years ago the river, in what is now China’s Szechuan Province, went through dry and wet cycles. The river bed, which Persons describes as a “dinosaur super-highway” has yielded plenty of full foot prints of other theropods and gigantic four-legged sauropods.
With just claw scratches on the river bottom to go with, Persons says the exact identity of the paddling dinosaur can’t be determined, but he suspects it could have been an early tyrannosaur or a Sinocalliopteryx. Both species of predators were known to have been in that area of China.
Persons is a U of A, PhD candidate and co-author of the research. It was published April 8 in the journal Chinese Science Bulletin.
Four Dinosaur Egg Species Identified in Lleida, Spain
Mar. 12, 2013 — A study headed by the Miquel Crusafont Catalan Palaeontology Institute has for the first time documented detailed records of dinosaur egg fossils in the Coll de Nargó archaeological site in Lleida, Spain. Up until now, only one type of dinosaur egg had been documented in the region
The archaeological site in Coll de Nargó containing dinosaur eggs lies some 8 kilometres to the west of the town that bears the same name in the province of Lleida. This region is home to different types of geological formations, including the Areniscas de Arén Formation and the Tremp Formation, which have provided a rich and varied yield of dinosaur fossils through the entire Pyrenees region.
“Eggshells, eggs and nests were found in abundance and they all belong to dinosaurs, sauropods in particular. Up until now, only one type of dinosaur egg had been documented in the region: Megaloolithus siruguei. After analysing more than 25 stratus throughout the Tremp Formation, a minimum of four different additional types were identified: Cairanoolithus roussetensis, Megaloolithus aureliensis, Megaloolithus siruguei and Megaloolithus baghensis,” as explained by Albert García Sellés from the Miquel Crusafont Catalan Palaeontology Institute and lead author of the study.
One of the main problems faced by palaeontologists when studying fossil remains is determining the age of the sediments that contain them. There are fossils known as “guide fossils” whose characteristics allow for the age of rocks to be deduced. However, these fossils are frequent in marine sediments but more scarce and difficult to find in land sediments.
“It has come to light that the different types of eggs (oospecies) are located at very specific time intervals. This allows us to create biochronological scales with a precise dating capacity. In short, thanks to the collection of oospecies found in Coll de Nargó we have been able to determine the age of the site at between 71 and 67 million years,” ensures the expert.
The paleontological sites in the south of Europe containing dinosaur remains have a high scientific value since they allow us to understand and thus reconstruct the ecosystems at the end of the Mesozoic Era.
The latest scientific investigations show that the dinosaur fauna of the European Continent living for a short time before the great extinction some 66 million years ago can be found exactly on the southern side of the Pyrenees.
A connection between French and Spanish dinosaurs
The discovery of Cairanoolithus fossils in this area is an important finding. Given that this type of eggs is only known in the south of France, they are the first of their kind found in the Iberian Peninsula.
According to García Sellés, this discovery constitutes a new proof of the connection between dinosaur fauna in France and in the Iberian Peninsula some 70 million years ago.
Furthermore, finding dinosaur eggs and nests in more than 25 stratigraphic levels provides clear evidence that these sauropods used the Coll de Nargó region as a nesting area for millions of years.
“We had never found so many nests in the one area before. In addition, the presence of various oospecies at the same level suggests that different types of dinosaurs shared the same nesting area,” concludes the scientist.
New Dinosaur Species: First Fossil Evidence Shows Small Crocs Fed On Baby Dinosaurs
Feb. 28, 2013 — A South Dakota School of Mines & Technology assistant professor and his team have discovered a new species of herbivorous dinosaur and today published the first fossil evidence of prehistoric crocodyliforms feeding on small dinosaurs.
Research by Clint Boyd, Ph.D., provides the first definitive evidence that plant-eating baby ornithopod dinosaurs were a food of choice for the crocodyliform, a now extinct relative of the crocodile family. While conducting their research, the team also discovered that this dinosaur prey was a previously unrecognized species of a small ornithopod dinosaur, which has yet to be named.
The evidence found in what is now known as the Grand Staircase Escalante-National Monument in southern Utah dates back to the late Cretaceous period, toward the end of the age of dinosaurs, and was published today in the online journal PLOS ONE. The complete research findings of Boyd and Stephanie K. Drumheller, of the University of Iowa and the University of Tennessee, and Terry A. Gates, of North Carolina State University and the Natural History Museum of Utah, can be accessed online (see journal reference below).
A large number of mostly tiny bits of dinosaur bones were recovered in groups at four locations within the Utah park — which paleontologists and geologists know as the Upper Cretaceous (Campanian) Kaiparowits Formation — leading paleontologists to believe that crocodyliforms had fed on baby dinosaurs 1-2 meters in total length.
Evidence shows bite marks on bone joints, as well as breakthrough proof of a crocodyliform tooth still embedded in a dinosaur femur.
The findings are significant because historically dinosaurs have been depicted as the dominant species. “The traditional ideas you see in popular literature are that when little baby dinosaurs are either coming out of a nesting grounds or out somewhere on their own, they are normally having to worry about the theropod dinosaurs, the things like raptors or, on bigger scales, the T. rex. So this kind of adds a new dimension,” Boyd said. “You had your dominant riverine carnivores, the crocodyliforms, attacking these herbivores as well, so they kind of had it coming from all sides.”
Based on teeth marks left on bones and the large amounts of fragments left behind, it is believed the crocodyliforms were also diminutive in size, perhaps no more than 2 meters long. A larger species of crocodyliform would have been more likely to gulp down its prey without leaving behind traces of “busted up” bone fragments.
Until now, paleontologists had direct evidence only of “very large crocodyliforms” interacting with “very large dinosaurs.”
“It’s not often that you get events from the fossil record that are action-related,” Boyd explained. “While you generally assume there was probably a lot more interaction going on, we didn’t have any of that preserved in the fossil record yet. This is the first time that we have definitive evidence that you had this kind of partitioning, of your smaller crocodyliforms attacking the smaller herbivorous dinosaurs,” he said, adding that this is only the second published instance of a crocodyliform tooth embedded in any prey animal in the fossil record.
“A lot of times you find material in close association or you can find some feeding marks or traces on the outside of the bone and you can hypothesize that maybe it was a certain animal doing this, but this was only the second time we have really good definitive evidence of a crocodyliform feeding on a prey animal and in this case an ornithischian dinosaur,” Boyd said.
The high concentrations of tiny dinosaur bones led researchers to conclude a type of selection occurred, that crocodyliforms were preferentially feeding on these miniature dinosaurs. “Maybe it was closer to a nesting ground where baby dinosaurs would have been more abundant, and so the smaller crocodyliforms were hanging out there getting a lunch,” Boyd added.
“When we started looking at all the other bones, we starting finding marks that are known to be diagnostic for crocodyliform feeding traces, so all that evidence coming together suddenly started to make sense as to why we were not finding good complete specimens of these little ornithischian dinosaurs,” Boyd explained. “Most of the bites marks are concentrated around the joints, which is where the crocodyliform would tend to bite, and then, when they do their pulling or the death roll that they tend to do, the ends of the bones tend to snap off more often than not in those actions. That’s why we were finding these fragmentary bones.”
In the process of their research, the team discovered through diagnostic cranial material that these baby prey are a new, as yet-to-be-named dinosaur species. Details on this new species will soon be published in another paper.
New Kind of Extinct Flying Reptile Discovered
Feb. 4, 2013 — A new kind of pterosaur, a flying reptile from the time of the dinosaurs, has been identified by scientists from the Transylvanian Museum Society in Romania, the University of Southampton in the UK and the Museau Nacional in Rio de Janiero, Brazil.
The fossilised bones come from the Late Cretaceous rocks of Sebeş-Glod in the Transylvanian Basin, Romania, which are approximately 68 million years old. The Transylvanian Basin is world-famous for its many Late Cretaceous fossils, including dinosaurs of many kinds, as well as fossilised mammals, turtles, lizards and ancient relatives of crocodiles.
A paper on the new species, named Eurazhdarcho langendorfensis has been published in the online journal PLoS ONE. Dr Darren Naish, from the University of Southampton’s Vertebrate Palaeontology Research Group, who helped identify the new species, says: “Eurazhdarcho belong to a group of pterosaurs called the azhdarchids. These were long-necked, long-beaked pterosaurs whose wings were strongly adapted for a soaring lifestyle. Several features of their wing and hind limb bones show that they could fold their wings up and walk on all fours when needed.
“With a three-metre wingspan, Eurazhdarcho would have been large, but not gigantic. This is true of many of the animals so far discovered in Romania; they were often unusually small compared to their relatives elsewhere.”
The discovery is the most complete example of an azhdarchid found in Europe so far and its discovery supports a long-argued theory about the behaviour of these types of creatures.
Dr Gareth Dyke, Senior Lecturer in Vertebrate Palaeontology, based at the National Oceanography Centre Southampton says: “Experts have argued for years over the lifestyle and behaviour of azhdarchids. It has been suggested that they grabbed prey from the water while in flight, that they patrolled wetlands and hunted in a heron or stork-like fashion, or that they were like gigantic sandpipers, hunting by pushing their long bills into mud.
“One of the newest ideas is that azhdarchids walked through forests, plains and other places in search of small animal prey. Eurazhdarcho supports this view of azhdarchids, since these fossils come from an inland, continental environment where there were forests and plains as well as large, meandering rivers and swampy regions.”
Fossils from the region show that there were several places where both giant azhdarchids and small azhdarchids lived side by side. Eurazhdarcho’s discovery indicates that there were many different animals hunting different prey in the region at the same time, demonstrating a much more complicated picture of the Late Cretaceous world than first thought.
Brain of Ampelosaur from Cuenca (Spain) Revealed
Jan. 23, 2013 — Scientists have made a 3D reconstruction of the remains of ampelosaur, found in 2007 in the site of Lo Hueco (Cuenca). The fossils are about 70 million years old (Late Cretaceous).
Up to now, only one species of the genus was known, Ampelosaurus atacis, which was discovered in France. The differences between the Spanish and the French fossils do not rule out that they could represent distinct species.
The researcher from the National Museum of Natural Sciences (CSIC) Fabien Knoll, who has conducted the investigation, considers that “more fossils are necessary to establish that we are dealing with a new species.” For this reason, the team has identified the specimen as Ampelosaurus sp., which leaves open its specific identity.
Little evolved brain
The ampelosaur pertains to the sauropod group, large-sized dinosaurs that settled widely during the Mesozoic Era (which began 253 million years ago and ended 66 million years ago). More precisely, it is a titanosaur, a group of plant eating animals that were dominant during the last half of the Cretaceous (last period of the Mesozoic). The first sauropods appeared about 160 million years earlier than the ampelosaur.
However, despite being the product of a long evolution, the brain of the ampelosaur does not show any notable development. Knoll explains: “This saurian may have reached 15 m in length; nonetheless its brain was not in excess of 8 cm.” According to the CSIC researcher: “Increase in brain size was not favored in the course of sauropod evolution.”
Another of the characteristics yielded by the reconstruction of the Cuenca ampelosaur brain is the small size of the inner ear. According to Knoll: “This may suggest that the ampelosaur would not have been adapted to quickly move either its eyes or its head and neck.”
In January of 2012, Knoll conducted the investigation that led to the reconstruction of another sauropod, Spinophorosaurus nigeriensis. The simulation in 3D of its brain revealed that that species, in contrast to what the study of the ampelosaur braincase demonstrated, presented a fairly well-developed inner ear.
According to the one of the researchers, “It is quite enigmatic that sauropods show such a diverse inner ear morphology whereas they have a very homogenous body shape; more investigation is definitely required.”