Description: This spectacular fossil comes from the twilight of the dinosaurs, the Hell Creek Formation. It is a vertebra of Triceratops, the cratopsian best known to the general public. Its name means “three horned face” an allusion to the long orbital horns and the nasal horn. It has often been shown in combat with Tyrannosaurus rex (as in the Filed Museum’s mural by Charles R. Knight), but the horns were most likely used as sexual display features to females or in threat displays and possibly ritual combat with other males. A pair of brow horns attached to the skull roof was found in 1887 and named by O.C. Marsh as Bison alticornis because he thought it belonged to an extinct bison, thus dispelling the notion that only E.D. Cope was capable of incorrectly assigning specimens (Marsh was only off by some 66 million years in age as well). At up to 9 meters in length and some 12,000 kg, this was one of the most formidable denizens of the terminal Cretaceous. Unlike several other ceratopsians, remains, while frequently discovered, have never been found in bonebeds that would indicate that they were herding animals. While this one would make a most impressive display, bear in mind that weight as well as size when considering purchase. While the dorsal processes have been repaired, it is still an essentially complete specimen, not a composite of bone and plaster. It was collected on private land, and as such is perfectly legal to own.