Troodontids facts for kids

Quick facts for kids Troodontids Temporal range: Late Jurassic–Late Cretaceous, 130–66Ma PreЄ Є O S D C P T J K Pg N
Mounted skeletal cast of an unnamed Alaskan troodontid, Perot Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Eumaniraptora
Family:	†Troodontidae Gilmore, 1924
Type species
Troodon formosus Leidy, 1856
Subgroups
†Albertavenator †Almas †Archaeornithoides? †Geminiraptor †Jianianhualong †Jinfengopteryx †Koparion? †Liaoningvenator †Paronychodon? †Sinornithoides †Talos †Tochisaurus †Xixiasaurus †Sinovenatorinae †Troodontinae
Synonyms
Saurornithoididae Barsbold, 1974

Troodontidae is a family of bird-like theropod dinosaurs. They were found mainly in Mongolia, China and North America. The first specimen, just a single tooth, was found in central Montana in 1855 by Ferdinand Hayden.

For a long time, troodontid fossils were few and scrappy. Recently more complete specimens have been found. There are now complete and articulated specimens, including feathers, eggs and embryos, and complete juveniles. In 1994 a fossil of an adult Troodon was found sitting on a nest with eight eggs.

Anatomical studies of the most primitive troodontids, like Sinovenator, demonstrate striking similarities with Archaeopteryx and primitive dromaeosaurids. This proves they are relatives: they are a clade called Paraves.

Replica skull of an undescribed troodontid, SPV 300/45.

The family have relatively large brains, a skull with many air pockets, a retractable second toe claw (it could be pulled in) and many teeth. The number of teeth ranges from 96 in Saurornithoides mongoliensis to 120 in the Troodon.

Taxonomy

• Family Troodontidae
  • Almas
  • Anchiornis
  • Archaeornithoides
  • Borogovia
  • Byronosaurus
  • Halszkaraptor
  • Jinfengopteryx
  • ?Koparion
  • Latenivenatrix
  • Mei
  • Saurornithoides
  • Sinornithoides
  • Sinusonasus
  • Sinovenator
  • Stenonychosaurus
  • Tochisaurus
  • Troodon (nomen dubium)
  • Urbacodon
  • Xixiasaurus
  • Zanabazar
• Undescribed/unnamed specimens
  • SPS 100/44 = EK troodontid
  • SPV 300/45 ("Lesse")
  • WDC DML 001 ("Lori")

Images for kids

• 

  Skull of the troodontid Saurornithoides mongoliensis.

• 

  Prismatoolithus levis eggs, which are considered to have been laid by a troodontid

• 

  Holotype specimen of Jinfengopteryx featuring elongated feathers

See also

In Spanish: Troodóntidos para niños