Temporal range: Late Cretaceous, 66 Ma
|Illustration of the vertebrae and sacrum|
|Species:||† A. sylvestris|
Agathaumas (//; "great wonder") is a dubious genus of a large ceratopsid dinosaur that lived in Wyoming during the Late Cretaceous (late Maastrichtian stage, 66 million years ago). The name comes from Greek, αγαν - 'much' and θαυμα - 'wonder'. It is estimated to have been 9 metres (30 ft) long and weighed 6 tonnes (5.9 long tons; 6.6 short tons), and was the largest land animal known at the time of its discovery.
It was the first ceratopsian known to science, though relatively little is known about it. The original specimen consisted only of the animal's hip bones, hip vertebrae and ribs, and because these bones vary little between ceratopsid species, it is usually considered a nomen dubium. It is provisionally considered a synonym of Triceratops, but is difficult to compare to that genus because it is only known from post-cranial remains.
The fossil remains of Agathaumas were first found in 1872 in southwestern Wyoming. They were discovered by Fielding Bradford Meek and H.M. Bannister while they were looking for fossil shells in the Lance Formation (then Laramie Formation) near the Black Butte and Bitter Creek. Meek and Bannister were employed by Ferdinand Hayden's Geological Survey of the Territories, and notified paleontologist Edward Drinker Cope of the find. Cope himself searched the ridge near Black Butte and re-discovered Meek's site, finding huge bones protruding from the rocks near a coal vein. The bones were preserved in sand and clay sediments, packed with fossil sticks and leaves, indicating a heavily forested habitat. Cope later (in 1873) described the skeleton as "the wreck of one of the princes among giants." Later in 1872, Cope published a description and name for the animal, Agathaumas sylvestris, or "marvelous forest-dweller," in reference to its great size and the environment revealed in the same rocks as its bones. The name Agathaumas has been cited as an example of Cope's excitement with this discovery, which was, at the time, the largest known land animal that had ever lived (until several years later, with the discovery of the giant sauropod dinosaurs of the Morrison Formation.
Cope and his team eventually recovered complete hip bones, sacral vertebrae, and several ribs from the animal. Since these were the first ceratopsian remains found, Cope was uncertain as to precisely what sort of dinosaur Agathaumas was (and for a time considered it a hadrosaur) until O. C. Marsh described Triceratops in 1889.
- Agathaumas sylvestris Cope, 1872; 16 vertebrae from the tail, sacrum and back, a partial pelvis and several ribs
Species previously referred to Agathaumas:
- A. flabellatus (Marsh, 1889/Scott, 1900); included with Triceratops horridus.
- A. milo (Cope, 1874); included with Thespesius occidentalis.
- A. monoclonius (Breihaupt, 1994); nomen dubium included with Monoclonius sphenocerus.
- A. mortuarius (Cope, 1874/Hay, 1902); nomen dubium included with Triceratops horridus.
- A. prorsus (Marsh, 1890/Lydekker, 1893); included with Triceratops prorsus.
- A. sphenocerus (Cope, 1890); nomen dubium included with Monoclonius sphenocerus.
Unfortunately, the bones of the rear half of the animal found are not particularly diagnostic in ceratopsians and Agathaumas remains a nomen dubium. No other remains have been found in the area, but based on its size and age of the rocks, it probably was a Triceratops.
In 1897, artist Charles R. Knight painted Agathaumas for Cope. Knight based the painting on the partial skull of the species Agathaumas sphenocerus, which had a large nasal horn and small horns over the eyes. This skull was originally referred to the genus Monoclonius and may actually belong to Styracosaurus. The body was based on a more complete skeleton of the species Triceratops prorsus that had been described by O.C. Marsh. At the time, Monoclonius, Agathaumas, and Triceratops were all thought to be close relatives that differed mainly in the arrangement of the horns and the presence of openings in the frill. This painting was later used as basis for a model Agathaumas in the 1925 film The Lost World.
- Breithaupt, B.H. (1999). "First Discovery of Dinosaurs in the American West." Pp. 59-65 in Gillette, D.D. (ed.), Vertebrate Paleontology In Utah. Utah Geological Survey. ISBN 1-55791-634-9, ISBN 978-1-55791-634-1
- Breithaupt, B.H. (2001). "Passport-In-Time Microvertebrate Fossil Project at the University of Wyoming Geological Museum: Late Cretaceous Paleontological Resources in the Public Eye." Pp. 107-112 in Santucci, V.L., and McClelland, L. (eds.), Proceedings of the 6th Fossil Resources Conference, United States Department of Interior - National Park Services - Geological Resources Division.
- Cope, E.D. (1873). "The monster of Mammoth Buttes." Pennsylvania Monthly, 4: 521-534.
- Cope, E.D. (1872). "On the existence of Dinosauria in the Transition Beds of Wyoming." Proceedings of the American Philosophical Society, 12: 481-483.
- Cope, E.D. (1889). "The horned Dinosauria of the Laramie." The American Naturalist, 23: 715-717.
- AMNH, Department of Vertebrate Paleontology. (1904). "Review List of Casts, Models, and Photographs of fossil Vertebrates." Supplement to Bulletin of the American Museum of Natural History, vol. 20.
- Sternberg, C. H. (1914). Notes on the Fossil Vertebrates Collected on the Cope Expedition to the Judith River and Cow Island Beds, Montana, in 1876. Science, 134-135.
- Peter Dodson; The Horned Dinosaurs (1996)
- Don Glut; The Dinosaur Scrapbook