Tiny Skull Illuminates the Lives of Giant Dinosaurs | Science

As far as dinosaurs go, Diplodocus was certainly one of the largest. Full grown adults could stretch more than 80 feet in length and weigh more than 13 tons. But, like all dinosaurs, these titans started off small. They hatched from eggs you could easily hold in your hand, starting their lives in a biological race to get a quick bite of the carnivorous ravenous teeth. A rare skull from one of these young dinosaurs is helping paleontologists better understand the perilous life of Diplodocus they started on their journey towards becoming giants.

University of Toronto paleontologist Cary Woodruff fossil "Andrew." The skull and first vertebra of the little giant were found among the 150 million-year-old strata in a particular spot called the Mother's Day Quarry Diplodocus were entombed. The skull is special for two reasons. "While over one hundred Diplodocus specimens are known, "Woodruff says," fewer than a dozen skulls exist, and of those, only a few animals. "Andrew adds to that list, and, on top of that, is the smallest Diplodocus skull yet known. The fossil is described today in Scientific Reports.

In life, Woodruff and colleagues estimate, Andrew would have been about 20 to 30 feet long. Much of that length would have been neck and tail. "For Andrew," Woodruff says, "imagine you took the body of a small cow and stuck a python on it." The juvenile Diplodocus found at the Mother's Day Woodruff says, these dinosaurs grew fast when they hatched from their eggs.

Andrew was not just a pint-sized version of an adult Diplodocus, though. In addition to being able to cuter-the large eyes and puppy-dog puppy-dog look-the muzzle and teeth of this dinosaur may indicate that it was living very differently than the grown-up sauropods.

Another young Diplodocus skull described in 2010 They are more narrowly defined than those of adults, Andrew's skull represents an even younger animal, and seems to take these trends further. Not only is Andrew's snout narrower, but the teeth at the back of the jaw are different than expected. Up until now, it seemed that Diplodocus only had peg-like teeth, but Andrew's rear teeth have a broader, "spatulate" shape associated with plucking coarse vegetation like conifers.

The reason these matters is that they could be related to these dinosaurs fed. "Macalester College paleontologist" has been shown to be a useful proxy for feeding behavior in living mammals, and this relationship has been applied to an array of dinosaur species. Kristi Curry Rogers says.

The basic idea is that grazers, which gobble down large amounts of low-quality plant food like grass, have broad, square muzzles, while browsers nip and pluck more nutritious, leafy foods with narrower or more rounded muzzles. The previously-discovered juvenile Diplodocus skull was used to support this argument for dinosaurs, and, Woodruff and colleagues proposes, so does Andrew.

Not that the new reconstruction is without caveats, however. Some of the skull bones missing from Andrew could significantly change the shape of the reconstruction skull. "One problem here is that the material is well-preserved enough to be sure of the interpretations," Curry Rogers says. A better-preserved skull would help dispel some of the areas of uncertainty.

If the skull reconstruction of Andrew is on the mark, however, Woodruff and colleagues proposes that the dietary difference could be something about the early lives of these dinosaurs. Over the past forty years, various examples of parental dinosaurs have been uncovered-parenting dinosaurs, and they have had to be fed, and other lines of evidence that some dinosaurs looked after their offspring.

But the evidence is different among dinosaurs like Diplodocus. These dinosaurs, it seems, ugly, they're off to their feet, and they're off to their feet.

Andrew's teeth support the idea that young Diplodocus were on their own from the beginning. "If an adult Diplodocus How did you get your young people from this type of tooth? "Woodruff asks. "If the adults are bringing these different types of plants, and if so, why, since they are not going to eat these plants for the rest of their lives?"

The team's hypothesis is that Andrew and the other juvenile Diplodocus in the Mother 's Day, but to really test this idea, more evidence is needed. "Curry Rogers says, quoting information from bone microstructure and postcranial anatomy to understand how diet and growth are connected for these dinosaurs.

These discussions are all part of a larger paleontological investigation of some of the largest animals to the Earth, and Andrew will no doubt play a continuing role. Aside from diet and behavior, in some ways Andrew's skull more closely resembles those of older sauropods than adult Diplodocus. "Andrew could help us understand the evolutionary history of Diplodocus, "Woodruff says, further opening windows into the deep past.

This little dinosaur may have a large impact on how we understand the Jurassic world.

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