Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Superorder: Dinosauria
Order: Ornithischia
Suborder: Cerapoda
Infraorder: Ceratopsia
Family: Ceratopsidae
Subfamily: Ceratopsinae
Genus: Triceratops

Triceratops is the exemplar of the ceratopsian suborder, and is perhaps the most recognizable dinosaur outside of academic circles. Living in the late Cretaceous right until the K-T boundary, it was among the largest ceratopsians known (averaging 8m to 9m in length and 3m in height), and bears the unmistakable triple horn arrangement that has been seared into collective consciousness. Although scientists have debated for nearly a century on the classification of the various specimens found, it is now widely believed that were only two species: T. Horridus and T. Prorsus. The differences are mainly morphological and small, such as variations in horn length or frill adornment.

Triceratops is notable for being one of the few ceratopsians with a solid frill. In other genera, large openings, or fenestrae, are usually found in the upper portions of the bony structure. These openings would serve to decrease the total weight of the skull. Their absence in Triceratops raises questions about the nature of these frills, and whether it was possible a solid frill had a greater potential for defence than a fenestrated one. A side benefit to their solidity is that skulls are found intact fairly regularly, and often in extreme abundance during their time periods.

Their horns were likely primarily used for intraspecies combat, and also as a deterrent against the large predators of the time, such as T. Rex. Rather than using any sort of charging penetration, Triceratops would have probably grappled and wrestled with competitors while locking horns or warding off advances.

Type Species: Triceratops horridus

Marsh, OC. (1888). A new family of horned Dinosauria, from the Cretaceous. American Journal of Science Vol. 36, pp. 477–478.

Marsh, OC. (1889). Notice of new American Dinosauria. American Journal of Science Vol 37, pp. 331–336.

Marsh, OC. (1889). Notice of gigantic horned Dinosauria from the Cretaceous. American Journal of Science Vol. 38, pp. 173–175.

Locality:

Wyoming, USA.

Scientific Resources:

Horner, JR; and Goodwin, MB. (2008). Ontogeny of Cranial Epi-Ossifications in Triceratops. Journal of Vertebrate Paleontology Vol. 28, Issue 1, pp. 134-144.

Mathews, JC; Henderson, M; and Williams, S. (2007). Taphonomy, Sedimentology, and Paleoenvironmental Reconstruction of a Unique Triceratops Site in the Hell Creek, Southeastern Montana. Geological Society of America Abstracts with Programs, Vol. 39, No. 3, p. 9.

Farke, AA. (2004). Horn Use in Triceratops (Dinosauria: Ceratopsidae): Testing Behavioral Hypotheses using Scale Models. Society of Vertebrate Paleontology, Vol 7, Issue 1.

Lehman, TM. (1987). Late Maastrichtian paleoenvironments and dinosaur biogeography in the western interior of North America. Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 60, No. 3-4, pp. 189-217.