Titanosaur Had Big Body, Small Brain, Major Appetite
A new titanosaur has just been found with one of the best-preserved skulls ever discovered for a dinosaur.
A new titanosaur dig includes one of the best dinosaur skulls ever discovered, allowing researchers to reconstruct everything from the dino's intellect -- or lack thereof -- to its senses and head posture.
Named Sarmientosaurus musacchioi, the new, small-brained dino had good eyesight, hearing tuned to low frequencies, and habitually held its head with its snout facing downward, according to a paper published in the journal PLOS ONE. The head was at the end of a long neck and featured a mouth full of sharp teeth.
The researchers believe that the plant-eating dinosaur lived life basically like a giant weed whacker, sweeping its neck over the ground to find plants that it would grab, but not chew.
"Sarmientosaurus had powerful teeth ... but those teeth did not chew," lead author Rubén Martínez of the Laboratorio de Paleovertebrados of the Universidad Nacional de la Patagonia San Juan Bosco told Discovery News. "(The teeth) would only cut the leaves and the dinosaur would eat them with almost no chewing."
Co-author Lawrence Witmer of the Ohio University Heritage College of Osteopathic Medicine added that the dinosaur "had a large feeding envelope. When you're as large as these sauropods were, being able to scarf down a lot of food without having to move saves a lot of energy."
Witmer estimates that the dinosaur, which lived roughly 95 million years ago, was about 40–50 feet long and weighed 8–12 tons. He and his colleagues consider it to have been a modest-sized titanosaur, given that others could grow to 90 feet in length and weigh as much as 50 tons. They were the largest animals ever to walk the earth.
The new species was excavated in southern Chubut Province, Argentina, near the town of Sarmiento, for which the dino was named. The species name also honors the late paleontologist Eduardo Musacchio, who was a friend of Martínez and other members of the team.
Of the 60 plus species of titanosaur that have been discovered so far, only four are represented by nearly or even reasonably complete skulls. They include Nemegtosaurus, Rapetosaurus, Tapuiasaurus, and now, possibly with the best preserved skull of all, Sarmientosaurus.
The dino certainly did not have a lot of brain matter to weigh down its head. The researchers estimate that the creature's brain was the size of a lime. Witmer said that "Sarmientosaurus certainly was no Einstein and was governed mostly by instinct. It probably had enough intelligence to have some fairly complicated behaviors, but this was not a clever animal by any means."
At least it could see and hear predators, like the meat-eating Megaraptor. Its cochlear duct was different from that of most other known titanosaurs, and enabled it to hear low-frequency sounds spread out over long distances. Witmer said the ability "could have helped the animals keep track of others in the herd as they spread out over the countryside."
He added that it might have been a primitive trait inherited from its ancestors. Sarmientosaurus appears to have been an intermediate species on the titanosaur family tree, providing a unique glimpse at evolution in action when compared with additional dinosaurs in the group.
The dinosaur's well-preserved inner ear, revealed via CT scanning, reveals that it habitually held its snout pointing downward with its eyes directed forward.
As for its long neck, Martínez said that the bones in it were extremely light and nearly hollow with up to 80 percent air.
It's the first non-bird dinosaur to preserve a bizarre structure in the neck that the researchers interpret to have been a long bony tendon. The scientists support the widely held view, however, that birds evolved from two-legged, meat-eating dinosaurs similar to Velociraptor and not from large plant-eaters like Sarmientosaurus.
They suspect that other plant-eating dinosaurs, known as sauropods, had the bony tendon, but that, for some reason, it didn't fossilize in them the way that it did in the Sarmientosaurus remains.
Paleontologist Matt Lamanna of the Carnegie Museum of Natural History told Discovery News that five new dinosaur species have been found so far at the site in Argentina, called Estancia Laguna Palacios. They include Notohypsilophodon (a fast-running plant eater), Aniksosaurus (a small meat eater thought to have roamed in packs or herds), Katepensaurus (Lamanna called it "a super-weird, probably broad-snouted and toothy low-browsing sauropod,") an as-of-yet unnamed new abelisaurid ("relative of the famous horned, bulldog-faced Carnotaurus and Majungasaurus") and now Sarmientosaurus.
Lamanna said that all "came from an area of just a few square miles. It's an awesome place."
Red blood cells and bone collagen fibers have just been recovered from 75-million-year-old dinosaur fossils. The findings, published in the journal Nature Communications, suggest that organic protein molecules remain intact for far longer than anyone had ever imagined. "We have several indications that the structures we found are consistent with red blood cells and collagen," lead author Sergio Bertazzo of Imperial College London's Department of Materials told Discovery News. The term "organic" in this instance is used in reference to a material, mainly composed of carbon, which is not the mineral present in the fossil.
For the study, the scientists applied extremely high magnification from electron microscopy and a tool called a "focused ion beam" to probe the fossils. The remains came from eight dinosaur bones that were not particularly well preserved. Some of the remains belonged to Chasmosaurus, a plant-eating, four-legged dinosaur with a head frill and horns.
Meat-eating dinosaurs were studied too, such as this claw from a carnivorous dinosaur that once roamed what is now Alberta, Canada. So far, the researchers have not detected DNA in the discovered cells. "We have found no evidence for DNA in the red blood cells we have found," co-author Susannah Maidment of Imperial College London's Department of Earth Science and Engineering told Discovery News. She added, "I think it would be unwise to say, "No, we'll never find DNA," because who knows what we might find in the future? Increasingly, studies like ours are showing that original components can be preserved in fossils. So maybe."
Prior research concluded that protein molecules decay in relatively short periods of time and cannot be preserved for longer than 4 million years. The new study clearly challenges that theory. What's more, the fossils the researchers studied were only in average condition, not having been pristinely preserved. Fossils such as the ones studied by Bertazzo in this image, and the ones museum goers see on display, could therefore still retain preserved organic remains too. In short, the presence of cells from soft tissues in dinosaur fossils could be much more common than previously thought.
The size, arrangement and structure of the fibers seen in this image -- taken of one of the dinosaur fossils -- are consistent with collagen from bone, according to the researchers. Collagen is the main structural protein found in animal connective tissues. Mature bone (and in this case, that's an understatement!) is composed of proteins and minerals. Approximately 30 percent of any bone is composed of organic compounds, of which 90–95 percent is collagen.
Most of the fossils studied by the scientists came from lower body parts, such as ribs and toe bones, and not the head area. This skull, held by Maidment, is a lasting reminder of what one of the dinosaurs looked like, however. The researchers took care to determine that the preserved cells did not come from another more modern species. The discovered red blood cells were comparable to those of living birds, such as emus, which the scientists also studied for comparison. Like the detected dino cells, "bird red blood cells are also oval and contain nuclei," Bertazzo explained, adding that "mammals are the only animals whose red blood cells do not contain nuclei, thus we can rule out contamination from a human." He continued, "The main difference between the dinosaur cells and those of birds is that the dinosaur cells seem to be quite a bit smaller. However, this is not surprising since they have been buried for 75 million years and have likely shrunk." He further added that blood cells size is extremely variable within different species.
This photo includes notes on the bottom, showing just some of the techniques the researchers employed in order to see and understand the fossils' internal composition. The green coloration corresponds to denser materials, while the red coloration picks up less dense materials, including the identified cells. Mary Higby Schweitzer is a paleontologist at North Carolina State University who is famous for leading teams that previously discovered blood cells in dinosaur fossils. She also later discovered soft tissue remains in
fossils. Schweitzer told Discovery News that the new findings confirm "our own contention that this type of preservation is more common than previously allowed, and that we should put a lot more effort into mining fossils for the information they contain." She continued that the paper is important "in showing what happens when you really look at ancient bone and are not bound by the expectation that nothing could possibly persist." Higby Schweitzer concluded, "If you don't look, you won't find. But if you do, you never know."
There is now tremendous hope that continued research on organic material in dinosaur fossils could lead to a better understanding of these still mysterious prehistoric animals. Maidment said, "The next questions we need to answer are how and why are these cells preserved, how far back in time does this style of preservation extend, and is it restricted to particular rock types and burial environments, or is it widespread in the geological record?" Ongoing mysteries that could be solved include resolving the debate on whether or not dinosaurs were warm or cold-blooded. It's even possible that some dinosaurs were ectothermic (cold blooded) while others evolved to become endothermic later, since today's birds are warm blooded. Bertazzo said, "If we could find red blood cells in many different types of dinosaurs, we might be able to look at the range of cell sizes and establish which dinosaurs had the fastest metabolism."