The “unicorn” dinosaur
During their heyday in the Cretaceous, the horned dinosaurs (or ceratopsians) displayed an impressive diversity of skulls shapes. Triceratops had a short frill and horns over its eyes and one its nose, while Styracosaurus had a long nose horn and as many as six horns ringing the edges of its frill. Others, like Protoceratops, didn’t have any horns at all. But one of the most bizarre arrangements was possessed by Pachyrhinosaurus:
Rather than having prominent horns on the nose and over the eyes, Pachyrhinosaurus had a huge, rough bump on the front of its face as well as a few smaller horns in the middle of its forehead, giving it a superficial connection to the mythical unicorn.
The first species of Pachyrhinosaurus canadensis was named in 1950, but now a second species has been announced in a monograph published by the National Research Council of Canada. Called Pachyrhinosaurus lakustai, the new species was named in honor of Al Lakusta, who in 1972 discovered the Alberta, Canada, bone bed in which this dinosaur was found. (Paleontologists started working on the site in the 1980s and it took many years of study to identify the new species.)
While many new dinosaurs are announced from single, partial skeletons, Lakustra had hit the fossil jackpot: He found a whole herd of Pachyrhinosaurus preserved together in one place. Not only were a large number of animals preserved together, but animals of different ages are in the same bed, meaning that researchers can now get a good look on how Pachyrhinosaurus grew and changed throughout its life.
But you don’t need to read a scientific paper to get a closer look at Pachyrhinosaurus. Paleontologist Lawrence Witmer and his colleagues have been taking advantage of the internet to present information that can’t be contained in a book.
Through his lab’s Website, Witmer, who contributed to the monograph, has released movies and exclusive reconstructions of the brain of Pachyrhinosaurus lakustai. Even if you don’t know very much about brains, the images the Witmer lab produced are absolutely stunning, and they have provided the basics of their discovery in plain language so everyone can understand what they found.
It’s not often that you get to look at the brain of an animal that has been dead for millions of years.
Photo courtesy of: Michael Skrepnick
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It has been suggested that the beaked dinosaurs who lived on coarse vegetation would have large cheek muscles to crunch with those beaks and that therefore they would look more like squirrels and less like vultures in the cheek region. That makes sense to me. Is there any evidence on the bones of large muscles?
One of the reasons it makes sense is that I recall from a long-ago botany course that some early trees (cycads?) developed seeds in the centre of the trunk, surrounded by wood, and depended on dinoasurs to eat the plant and liberate the seed. When the dinos died out, so did those plants that depended on them.
Similarly, it is likely that heavy fruits like the Osage orange and possibly even the black walnut were spread more by giant ground sloths than anything else–which might explain why Osage oranges are uncommon these days.
Comment by Monado — October 14, 2008 @ 3:01 pm
[...] of the Arctic Circle, on Alaska’s North Slope, lie the scattered remains of dinosaurs like the horned Pachyrhinosaurus, the tyrannosaur Gorgosaurus, the hadrosaur Edmontosaurus, and the maniraptorans Troodon and [...]
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