TROODON
a meat-eating troodontid theropod dinosaur from the Late Cretaceous of North America.
Pronunciation: TRO-wuh-don
Meaning: Wounding tooth
Author/s: Leidy (
1856)
Synonyms: See
below
First Discovery: Montana, USA
Discovery Chart Position: #14
Troodon formosus
Discovered in 1855, Troodon was one of the first dinosaurs described from North America. Problem is, its first known remains amount to a single tooth found in the the Judith river badlands of Fergus County, and we all know the problems that arise from naming dinosaurs on the strength of a single tooth.
Update coming soon...
Etymology
Troodon was originally spelled Troödon by Joseph Leidy in 1856, but was amended by Sauvage in 1876. The name means "Wounding Tooth", from the Greek "troo" (wound, injure, pierce) and "odon" (tooth), because its curved teeth bore jagged upwards-pointing serrations. Funnily enough, this design is more commonly seen in the teeth of herbivorous reptiles.
The
species epithet,
formosus, means "handsome", "well formed" or "pleasing" in Latin.
Synonyms
Polyodontosaurus (Gilmore, 1932)
Stenonychosaurus? (Sternberg, 1932)
Discovery
The first fossil of
Troodon was discovered in the Judith River Formation of Fergus County, Montana, USA by Dr F. V. Hayden in 1855.
The
holotype (ANSP 9259) is a single tooth.
Estimations
Timeline:
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Campanian
Age range: 80-73 mya
Stats:
Est. max. length: 2.5 meters
Est. max. hip height: 0.8 meters
Est. max. weight: 40 Kg
Diet: Omnivore
Other Species
Troodon inequalis is the Canadian representative of
Troodon that Sternberg originally named
Stenonychosaurus inequalis based on a foot, fragments of a hand, and some tail vertebrae found in the Dinosaur Park Formation in 1932. The most complete specimen of
Stenonychosaurus was described in 1969 by Dale Russell who also created its hypothetical humanoid descendant known as "the dinosauroid".
Stenonychosaurus was sunk into
Troodon formosus in 1987 by Phil Currie, who performed a flip-flop in 2005, and now refers to the Canadian
Troodon material as
Troodon inequalis.
Troodon bakkeri was coined in 1991 by Olshevsky for remains from Wyoming's Lance Formation that Carpenter originally named
Pectinodon ("comb tooth") in 1982.
Pectinodon and its various species were all sunk into
Troodon formosus by Currie in 1987. But this turned out to be a wasted exercise, as latest research found
Pectinodon to be distinct and valid afterall.
Troodon asiamericanus was originally named
Pectinodon asiamericanus by Nessov in 1995 for a tooth (CCMGE 49/12176) from the Cenomanian-aged Khodzhakul Formation of Uzbekistan. It would have benefitted from
Pectinodon being reinstated as a valid critter. However, most experts dismiss it as a nomen dubium.
References
• Leidy J (1856) "
Notices of remains of extinct reptiles and fishes, discovered by Dr. F. V. Hayden in the bad lands of the Judith River, Nebraska Territory".
Proceedings of the Academy of Natural Sciences of Philadelphia, 8(7): 72-73.
• Sauvage H-E (1876) "Notes sur les reptiles fossiles".
Bulletin de la Société géologique de France (3e série 4). Société géologique de France: 434-444.
• Nopcsa F (1901) "A dinosaurusok átnézete és származása" [Review and origin of dinosaurs].
Földtani Közlöny, 31: 193-279.
• Gilmore CW (1924) "On
Troodon validus, an orthopodous dinosaur from the Belly River Cretaceous of Alberta, Canada".
Department of Geology, University of Alberta Bulletin, 1: 1-43.
• Gilmore CW (1931) "
A new species of troodont dinosaur from the Lance Formation of Wyoming".
Proceedings of the United States National Museum, 79(2875): 1–6. DOI: 10.5479/si.00963801.79-2875.1. [Troodon wyomingensis.]
• Brown B and Schlaikjer EM (1943) "
A study of the troodont dinosaurs with the description of a new genus and four species".
Bulletin of the AMNH, 82(5): 119-149.
• Sternberg C (1945) "Pachycephalosauridae proposed for domeheaded dinosaurs,
Stegoceras lambei n. sp., described".
Journal of Paleontology, 19: 534-538.
• Bohlin B (1953) "Fossil reptiles from Mongolia and Kansu. Reports from the Scientific Expedition to the North-western Provinces of China under Leadership of Dr. Sven Hedin. VI. Vertebrate Palaeontology 6".
The Sino-Swedish Expedition Publication, 37: 1–113. [Troodon bexelli.]
• Russell DA and Séguin R (1982) "
Reconstruction of the small Cretaceous theropod Stenonychosaurus inequalis and a hypothetical dinosauroid".
Syllogeus, 37: 1-43.
• Paul GS (1988) "
Predatory Dinosaurs of the World".
• Carpenter K and Currie PJ (1992) "
Dinosaur Systematics: Approaches and Perspectives".
• Nessov L (1995) "Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography".
Editorial Council, Geology Faculty, St. Petersburg State University: 1-156.
• Varricchio DJ, Jackson F, Borkowski JJ and Horner JR (1997) "Nest and egg clutches of the dinosaur
Troodon formosus and the evolution of avian reproductive traits".
Nature, 385(6613): 247-250. DOI: 10.1038/385247a0.
• Holtz TR Jr, Brinkman DL and Chandler CL (1998) "Denticle morphometrics and a possibly omnivorous feeding habit for the theropod dinosaur
Troodon".
Gaia, 15: 159-166.
• Currie PJ and Koppelhus EB (2005) "Theropods, including birds". Page 367-397 in Currie and Koppelhus "
Dinosaur Provincial Park, a spectacular ecosystem revealed".
• Zanno LE, Varricchio DJ, O'Connor PM, Titus AL and Knell MJ (2011) "A new troodontid theropod,
Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America".
PLOS ONE, 6(9): e24487. DOI: 10.1371/journal.pone.0024487.
• van der Reest AJ and Currie PJ (2017) "Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: implications for deinonychosaur diversity in North America".
Canadian Journal of Earth Sciences, 54(9): 919-935. DOI: 10.1139/cjes-2017-0031.
• Tagliavento M, Davies AJ, Bernecker M, Staudigel PT, Dawson RR, Dietzel M, Götschl K, Guo W, Schulp AS, Therrien F, Zelenitsky DK, Gerdes A, Müller W and Fiebig J (2023) "Evidence for heterothermic endothermy and reptile-like eggshell mineralization in
Troodon, a non-avian maniraptoran theropod".
Proceedings of the National Academy of Sciences, 120(15): e2213987120. DOI: 10.1073/pnas.2213987120.
• Varricchio DJ, Hogan JD and Gardner JD ( 2025) "Troodontid specimens from the Cretaceous Two Medicine Formation of Montana (USA) and the validity of
Troodon formosus".
Journal of Paleontology, 99(1): 219-240. DOI: 10.1017/jpa.2024.67.
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"
TROODON :: from DinoChecker's dinosaur archive".
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