Troodontidae

Troodontidae is a family of bird-like theropod dinosaurs.The word is pronounced "Troödontidae", that is, the two letters o are pronounced separately. 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.Mackovicky, Peter J. & Norell, Mark A. 2004. Troodontidae. In Weishampel, David B; Dodson, Peter & Osmólska, Halszka. The Dinosauria. 2nd ed, Berkeley: University of California Press. pp. 184–195. 

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.Norell, Mark A. et al 1994. A theropod dinosaur embryo and the affinities of the Flaming Cliffs dinosaur eggs. Science 266 (5186): 779–782. PMID 17730398

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. thumb|250px|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")

 References 

Category:Theropods