Agathaumas
Agathaumas | |
---|---|
Illustration of the vertebrae and sacrum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | †Ornithischia |
Clade: | †Ceratopsia |
Family: | †Ceratopsidae |
Subfamily: | †Chasmosaurinae |
Tribe: | †Triceratopsini |
Genus: | †Agathaumas Cope, 1872 |
Type species | |
†Agathaumas sylvestris Cope, 1872
| |
Species | |
See text |
Agathaumas (
It was the first ceratopsian known to science from more than teeth, 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 postcranial remains.[1][2]
History
The
Classification history
Cope originally did not know to what group Agathaumas belonged, though he noted that some of the remains were similar to the British reptile Cetiosaurus[4] and very different from the corresponding elements of Hadrosaurus and Dryptosaurus (Laelaps).[4] In 1882, Othniel Charles Marsh, Cope's rival in the Bone Wars, suggested that Agathaumas, along with Cionodon, another Cope taxon, was a Hadrosaurid.[5] In 1883, with his description of the skull of Edmontosaurus (Diclonius), Cope also suggested that his taxa Agathaumas, Monoclonius, and Dysganus could be Hadrosaurids.[6] Cope did not assign Agathaumas into the group now recognized as Ceratopsia until later in 1889, when Cope recognized that his genera Monoclonius and Polyonax were related due to Marsh's description of Triceratops fossils.[7] Marsh had already named a group for the horned dinosaurs, Ceratopsidae, but Cope did not recognize this family name as he believed Ceratops could not be distinguished from other taxa; Cope erected a new name, Agathaumidae.[7] Cope later named 2 more "Agathaumids", Manospondylus gigas and Claorhynchus trihedrus, based on fragmentary fossils in 1892, expanding his group to 5 genera.[8]
After reassessment by John Bell Hatcher, Richard Swann Lull, and Nelda Wright in the 1900s and 1930s, all of the members of Agathaumidae were found to be dubious,[9][10] and the family name Ceratopsidae was preferred over Agathaumidae.[9] Agathaumas itself was found to be a dubious Ceratopsid by Hatcher and Lull,[9] as well as by John Ostrom and Peter Wellnhofer who placed it as Triceratops sp.[11]
Species
Type:
- 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) Burkhardt, 1892; alternative combination for Triceratops flabellatus;[12] synonymous with Triceratops horridus.[13]
- A. milo Cope, 1874; included with Thespesius occidentalis by Cope, dubious at Hadrosauridae family level.[14]
- A. monoclonius Breithaupt, 1994; nomen dubium included with Monoclonius sphenocerus
- A. mortuarius (Cope, 1874) Hay, 1901; nomen dubium, alternative combination for Polyonax mortuarius; possible synonym of Triceratops horridus[14]
- A. prorsus (Marsh, 1890) Lydekker, 1893; alternative combination of Triceratops prorsus, unused since
- A. sphenocerus (Cope, 1889) Ballou, 1897; nomen dubium included with Monoclonius sphenocerus[15]
Unfortunately, due to the fragmentary nature of Agathaumas sylvestris’ holotype specimen, Agathaumas is a dubious taxon and cannot be referred beyond Ceratopsidae.[9] based on stratigraphy it is likely a member of Triceratopsini.[1]
Knight's restoration
In 1897, paleoartist Charles R. Knight painted "Agathaumas sphenocerus" for an article in The Century Magazine under the supervision of Edward Drinker Cope.[15] The nasal horn and brow horns were based on "Monoclonius" sphenocerus (possible synonym of Centrosaurus apertus) and "Monoclonius" recurvicornis (unnamed genus similar to Einiosaurus) respectively, which were found in the Judith River Formation in Montana and named by Cope in 1889.[7][16] The rest of the skull and body were based on an 1891 skeletal reconstruction of Triceratops prorsus by Othniel Charles Marsh.[16][17] The armor was based on isolated elements from the Lance Formation in Wyoming that Marsh erroneously referred to Triceratops in 1891: the spines on the frill were a Denversaurus schlessmani cervical spine, the scutes on the flank were indeterminate ankylosaurian osteoderms (either Denversaurus or Ankylosaurus magniventris), and the spikes on the back were a Pachycephalosaurus wyomingensis squamosal horn.[16][18] The name Agathaumas was arbitrarily used for Knight's depiction and no parts were based on A. sylvestris.[16] His painting inspired a stop motion model created by Marcel Delgado that appeared in the 1925 film The Lost World.[19]
See also
References
- ^ 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.
- ^ a b c Cope, E.D. (1872). "On the existence of Dinosauria in the Transition Beds of Wyoming". Proceedings of the American Philosophical Society. 12: 481–483.
- ^ Marsh, O. C. (1882). "Classification of the Dinosauria". American Journal of Science. 3 (133): 81–86.
- JSTOR 4060861.
- ^ a b c Cope, E.D. (1889). "The horned Dinosauria of the Laramie". The American Naturalist. 23 (272): 715–717.
- ^ Cope, E. D. (1892). Fourth note on the Dinosauria of the Laramie.
- ^ US Government Printing Office.
- ^ Lull, R. S., & Wright, N. E. (1942). Hadrosaurian dinosaurs of North America (Vol. 40). Geological Society of America.
- ^ Ostrom, J. H.; Wellnhofer, P. (1985). "The Munich specimen of Triceratops with a revision of the genus". Zitteliana. 14: 111–158.
- ^ Burkhardt, R., 1892. "Das Gehirn von Agathaumas flabellatus Marsh". Neues Jahrbuch für Mineralogie, Geologie und Paläontologie 1892: 71-72
- ^ Forster, C. A. (1996). Species resolution in Triceratops: cladistic and morphometric approaches. Journal of Vertebrate Paleontology, 16(2), 259-270.
- ^ a b Carpenter, K., & Young, D. B. (2002). Late Cretaceous dinosaurs from the Denver Basin, Colorado. Rocky Mountain Geology, 37(2), 237-254.
- ^ a b Ballou, W.H. (1897). "Strange creatures of the past. Gigantic saurians of the reptilian age". The Century Magazine. 55 (1): 15–23.
- ^ a b c d Greenfield, T. (2023). "Armor for Agathaumas: The fossils behind Charles Knight's famous painting". Prehistoric Magazine. 25: 24–30.
- ^ Marsh, O.C. (1891). "Restoration of Triceratops". The American Journal of Science. Series 3. 41 (244): 339–342.
- ^ Marsh, O.C. (1891). "The gigantic Ceratopsidae, or horned dinosaurs, of North America". The American Journal of Science. Series 3. 41 (242): 167–178.
- ^ Painter, D. (2011). "The marvelous movie menagerie of Marcel Delgado". Movie Collector's World. 755: 17–19.
- Dodson, Peter (1996). The Horned Dinosaurs.
- Glut, Don. The Dinosaur Scrapbook.