Troodon formosus
Pronunciación: TROH-oh-don for-MOH-sus
Maniraptora · Troodontidae
A small, big-brained, bird-like predator from the Late Cretaceous of North America, named in 1856 from a single tooth. Nests from Montana suggest that males brooded the eggs. Whether the name is still usable is debated.
- Bipedal
- Feathered
- Sickle claw
- Eggs known
- Período
- Cretácico· Campaniense
- Dieta
- Carnívoro
- Longitud
- Desconocido
- Masa
- Desconocido
- Ubicación
- Montana, Alberta, United States, Canada
Respuestas rápidas
- ¿Qué tamaño tenía Troodon formosus?
- Alcanzaba unos 0,8–1 m de altura a la cadera. (Paul 2016)
- ¿Cuándo vivió Troodon formosus?
- Troodon formosus vivió durante el Cretácico Superior, hace unos 79,5–74,4 millones de años. (Paleobiology Database: Troodon occurrences 2026; Rogers et al. 2016)
- ¿Dónde se han encontrado fósiles de Troodon formosus?
- Se han encontrado fósiles de Troodon formosus en Judith River Formation (Montana), Dinosaur Park Formation (Alberta), United States y Canada. (Leidy 1856; Varricchio et al. 1997)
- ¿Qué comía Troodon formosus?
- Troodon formosus era carnívoro u omnívoro. (Leidy 1856; Varricchio et al. 1997)
- ¿Quién nombró a Troodon formosus y cuándo?
- Troodon formosus fue descrito por Joseph Leidy en 1856. (Leidy 1856; Paleobiology Database: Troodon occurrences 2026)
En esta página
TROH-oh-don for-MOH-sus
- Período
- Cretácico79,5–74,4 Ma
- Dieta
- Carnívoro
- Longitud
- Desconocido
- Masa
- Desconocido
- Ubicación
- United States, Canada
- Clasificación
- Maniraptora · Troodontidae
- Descrito
- 1856, Joseph Leidy
Resumen
Este contenido está disponible en inglés.
Troodon formosus was named by Joseph Leidy in 1856 from one serrated tooth collected by Ferdinand Hayden in 1855 in the Judith River badlands of Montana. For more than a century it was one of the earliest-named North American dinosaurs, and many small troodontid skeletons from the Campanian of Montana and Alberta were referred to it.
Troodontids were slender, long-legged predators with large eyes, big brains for dinosaurs and an enlarged, retractable second toe claw. Clutches of paired, elongated eggs from Egg Mountain in Montana, some with an adult on top, have been attributed to Troodon (Varricchio et al. 1997).
The clutches are large relative to the adults, and the brooding adults lack the bone features of egg-laying females, which suggests that males cared for the eggs, as in many living birds (Varricchio et al. 2008). A single tooth cannot separate closely related species, so several authors treat Troodon formosus as a doubtful name and use Stenonychosaurus for the Canadian skeletons.
Significado del nombre
"Wounding tooth", from Greek trōō ("to wound") and odous ("tooth"), for its serrated teeth; formosus, Latin for "beautiful" (Leidy 1856).
Biología y evidencia
Lo que piensan los científicos sobre cómo vivía este animal y qué tan sólida es la evidencia de cada idea.
Huevos
Troodon laid its eggs in pairs in a partly buried clutch.
Nivel de evidencia: Evidencia moderadaClutches from Montana show paired eggs, which suggests two working oviducts laying one egg each at intervals. The attribution of the eggs to Troodon itself rests on associated skeletons.
Evidencia a favor / en contra · 1
Evidencia a favor
Espécimen · Egg Mountain troodontid clutches
Clutches of paired, elongated eggs from the Two Medicine Formation of Montana, attributed to Troodon, some associated with adults.
Anidación
Troodon fathers brooded the eggs.
Nivel de evidencia: HipótesisThe clutches are very large for the adults, as in birds where males incubate, and the adults on the nests show no signs of recent egg-laying. Care by males may have evolved before birds.
Evidencia a favor / en contra · 2
Evidencia a favor
Histología · Clutch volume and brooding-adult histology
Large clutch volumes scale with a bird paternal-care model, and the adults found on clutches lack the bone features of egg-laying females.
Espécimen · Egg Mountain troodontid clutches
Clutches of paired, elongated eggs from the Two Medicine Formation of Montana, attributed to Troodon, some associated with adults.
Otros
Troodon formosus, based on a single tooth, is a valid name.
Nivel de evidencia: En disputaA 2017 study found the type tooth undiagnostic and revived Stenonychosaurus for Canadian skeletons; later work has proposed a neotype to keep Troodon. Which name applies to which fossils is unsettled.
Evidencia a favor / en contra · 1
Evidencia a favor
Espécimen · Egg Mountain troodontid clutches
Clutches of paired, elongated eggs from the Two Medicine Formation of Montana, attributed to Troodon, some associated with adults.
Tamaño
- Longitud
- Desconocido
- Altura
- 0,9 mrango publicado 0,8–1 m
- Masa
- Desconocido
(3 pies)
Longitud desconocida, así que aún no hay comparación de tamaño.
Línea de tiempo
Períodos: Campaniense (83,6–72,1 Ma), Cretácico Superior (100,5–66 Ma)
Span of its formations: the Judith River Formation of the type area, about 79.5-75.2 Ma (Ar/Ar, Rogers et al. 2016, read in a secondary summary only), and the Dinosaur Park Formation, 76.47-74.44 Ma (Eberth et al. 2023). The type tooth is not tied to a dated level and referred material is debated.
Ubicación
Formaciones
- Judith River Formation · Montana
- Dinosaur Park Formation · Alberta
- Judith River badlands, Fergus County, Montana · Judith River Formation · Montana · posición aproximada
Estos son los lugares donde se han encontrado fósiles, no toda el área donde vivía el animal.
Ecosistema
Vivió en: Dinosaur Park
hace 76,5–74,4 millones de años · llanura aluvial, llanura costera, sistema fluvial
Late Campanian alluvial and coastal plains on the western shore of the Western Interior Seaway, in what is now southern Alberta.
Mismo ecosistema
Mismo ecosistema
Mismo ecosistema
Clasificación
- cladoDinosauria
- cladoSaurischia
- cladoTheropoda
- cladoCoelurosauria
- cladoManiraptora
- familiaTroodontidae
- géneroTroodon
- especieTroodon formosus
Estado taxonómico: Válido
Registro fósil
| Número de catálogo | Estado | Institución | Hallado |
|---|---|---|---|
| ANSP 9259 | Holotipo | Academy of Natural Sciences of Drexel University (ANSP) | 1855 |
Lo que se ha encontrado
Holotipo: ANSP 9259
- Conservado
- Parcial
- Reconstruido
- Desconocido / no registrado
Región por región (tabla)
| Región | Estado |
|---|---|
| Skull | Desconocido / no registrado |
| Mandible | Desconocido / no registrado |
| Teeth | Parcial · One tooth. |
| Cervical vertebrae | Desconocido / no registrado |
| Dorsal vertebrae | Desconocido / no registrado |
| Sacrum | Desconocido / no registrado |
| Caudal vertebrae | Desconocido / no registrado |
| Ribs | Desconocido / no registrado |
| Gastralia | Desconocido / no registrado |
| Scapula / shoulder girdle | Desconocido / no registrado |
| Humerus | Desconocido / no registrado |
| Forearm (radius / ulna) | Desconocido / no registrado |
| Hand (manus) | Desconocido / no registrado |
| Pelvis | Desconocido / no registrado |
| Femur | Desconocido / no registrado |
| Tibia / fibula | Desconocido / no registrado |
| Foot (pes) | Desconocido / no registrado |
Descubrimiento
- Año de descripción
- 1856
- Descrito por
- Joseph Leidy
- Espécimen tipo
- ANSP 9259
Cronología del descubrimiento
1856 · Descrito formalmente
Leidy names Troodon from a tooth
Leidy names Troödon formosus from a tooth collected by Hayden in 1855.
Personas: Joseph Leidy, Ferdinand V. Hayden
1997 · Estudio importante
Troodon nests described from Egg Mountain
Varricchio and colleagues describe clutches and nests from Montana.
Personas: David J. Varricchio
2008 · Estudio importante
Paternal care proposed for Troodon
Clutch size and bone histology suggest males brooded the eggs.
Personas: David J. Varricchio
Fuentes
- (2026). Paleobiology Database: Troodon occurrences. The Paleobiology Database (paleobiodb.org), data service 1.2, accessed 2026-09-23. https://paleobiodb.org/data1.2/occs/list.txt?base_name=Troodon&show=coords,paleoloc,strat,loc,ref&pgm=gplates (se abre en una pestaña nueva)
- Eberth, D. A., Evans, D. C., Ramezani, J., Kamo, S. L., Brown, C. M., Currie, P. J. & Braman, D. R. (2023). Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U-Pb geochronology. Canadian Journal of Earth Sciences. doi:10.1139/cjes-2023-0037 (se abre en una pestaña nueva)
- 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.
- Paul, G. S. (2016). The Princeton Field Guide to Dinosaurs (2nd edition). Princeton University Press.
- Rogers, R. R. et al. (2016). Age, correlation, and lithostratigraphic revision of the Upper Cretaceous (Campanian) Judith River Formation in its type area (north-central Montana), with a comparison of low- and high-accommodation alluvial records. The Journal of Geology 124(1). doi:10.1086/684289 (se abre en una pestaña nueva)
- Varricchio, D. J., Jackson, F., Borkowski, J. J. & Horner, J. R. (1997). Nest and egg clutches of the dinosaur Troodon formosus and the evolution of avian reproductive traits. Nature 385: 247-250. doi:10.1038/385247a0 (se abre en una pestaña nueva)
- Varricchio, D. J., Moore, J. R., Erickson, G. M., Norell, M. A., Jackson, F. D. & Borkowski, J. J. (2008). Avian paternal care had dinosaur origin. Science 322: 1826-1828. doi:10.1126/science.1163245 (se abre en una pestaña nueva)