Christian Science Monitor: The peculiar dinosaurs of Laramidia: weird horns and more
The creatures' arrangement of horns are unique among the broader group of dinosaurs they belong to, a group that includes animals such as Triceratops.
Moreover, the find appears to lends support to a contentious notion that dinosaurs were quite provincial on Laramidia. The same broad groups of large dinosaurs were present along the north-south reach of the narrow continent, but the species within each broad group differed north and south.
This contrasts with the appearance of large animals in the fossil record from more-recent times. During the last ice age, for example, one could hop into a hypothetical Land Rover, drive from the east coast to the west coast, marvel at the mammoths, mastodons, and giant sloths along the way, and each is "pretty much the same species from the Atlantic coast to the La Brea tar pits," says Thomas Holtz Jr., a paleontologist at the University of Maryland in College Park. ...