August 21, 2012
About a year ago, I briefly joined the Carthage College and Burpee Museum of Natural History field crews as they searched the Hell Creek Formation around Ekalaka, Montana. There were bits of Triceratops strewn across the landscape. Even though I only spent a few days among the rolling grasslands and islands of Late Cretaceous outcrop, there wasn’t a day that went by that I didn’t see at least a fragment of the great three-horned herbivore–from isolated teeth to skulls that had crumbled apart, Triceratops was a constant companion. Indeed, as Jack Horner and colleagues affirmed in a census of Hell Creek fossils last year, Triceratops is the most commonly-found dinosaur in this swath of Late Cretaceous North America.
Move a little to the north, though, and the trail of Triceratops fades. While I was virtually tripping over Triceratops everywhere I went in eastern Montana, the gigantic ceratopsian isn’t quite so abundant in Saskatchewan and is a rarity in the Late Cretaceous rock of Alberta. So while paleontologists have already discovered many Triceratops specimens from the United States, Canadian paleontologists made headlines last week when they found what appears to be an especially big representative of this famous dinosaur in Alberta.
The CBC, Calgary Herald, Edmonton Journal and other news outlets have covered the story. Earlier this summer, former Royal Tyrrell Museum employee Tim Schowalter stumbled across the Triceratops site on an old road cut near Drumheller (a place famous for its proximity to dinosaur-rich badlands). From there, Royal Tyrrell Museum paleontologist François Therrien led the excavation of the Triceratops “log jam.” Included in the lot are large vertebrae and ribs over six feet long, indicating that this was a Triceratops of considerable size. Unfortunately, though, the site contains only a partial skeleton, and the dinosaur’s skull seems to be missing. The official Royal Tyrrell Museum Twitter account said that “there are some odd looking bones that could be cranial”, but explained that the institution’s paleontologists will have to prepare the bones before they can be sure.
Without a skull, this new Triceratops won’t have much effect on the ongoing debate over whether Torosaurus is really just a grown-up Triceratops or a distinct genus or dinosaur. That discussion has relied almost entirely on the skulls of these dinosaurs–as far as we know, the only reliable way to tell the two forms apart. But, as Therrien commented in some news reports, the newly-uncovered dinosaur may help paleontologists determine whether there were significant variations between Triceratops that lived in Montana, Saskatchewan and Alberta. The dinosaur is a new point of reference as paleontologists examine the record of Triceratops. And, after all, every dinosaur skeleton contains various clues about how that individual lived. The trick is carefully extracting those threads in order to flesh out the ancient lives of the dinosaurs.
February 24, 2012
Anchiceratops ornatus was a pretty successful dinosaur. The single known species of this elaborately horned herbivore survived for about two millions years during the Late Cretaceous—many thousands of years longer than the varieties of horned dinosaur which preceded it in prehistoric Canada. This is a recent realization. As I wrote last September, what were once thought to be two different species of Anchiceratops were actually one, and the idea that paleontologists have found both male and female forms of this dinosaur has also been struck down.
These changes stemmed from a better understanding of dinosaur variation. Often, small differences between dinosaur skeletons led paleontologists to establish new species or genera of dinosaur when those subtle variations were really just signs of individual disparity within a species. In the latest Royal Tyrrell Museum lecture, paleontologist Jordan Mallon, the lead author on the Anchiceratops paper, explains how he tracked variations among fossils to give us a better idea of dinosaur diversity and evolution.
[Hat-tip to ReBecca Hunt-Foster for sharing the video]
January 30, 2012
About 110 million years ago, an ankylosaur settled on the bottom of a Cretaceous sea. This was no place for a dinosaur. No dinosaurs were adapted to a marine lifestyle, and the heavily armored ankylosaurs were probably the least suited to paddling around in the water. Yet, almost a year ago, shovel operator Shawn Funk found an ankylosaur in the marine, Early Cretaceous sediments at a Suncor mine in northern Alberta. How did the dinosaur get there?
Donald Henderson, curator of dinosaurs at the Royal Tyrrell Museum, explained how this dinosaur died, was preserved and was discovered in a recent lecture for the Royal Tyrrell Museum Speaker Series. Almost everything about the discovery was lucky. The dinosaur just happened to settle in a place where sediment quickly covered its body; the carcass was not torn apart by scavengers; the shovel operator who stumbled across the ankylosaur recognized that he found something potentially significant and the discovery of the dinosaur in the mine meant that paleontologists had lots of heavy machinery on hand to help excavate the skeleton.
But the strangest aspect of the find is the ecological context of the dinosaur. This ankylosaur must have lived along the coastline of the great Western Interior Seaway which once split North America into two. But that was many, many miles away from where the skeleton was found. Exactly how the dinosaur died is unknown, but as Henderson notes, the carcass undoubtedly floated upside-down through the sea. The gases from decomposition gave the body enough buoyancy to travel—what paleontologists commonly refer to as a “bloat and float” scenario.