Troodontidae is a clade of bird-like theropod dinosaurs from the Late Jurassic to Late Cretaceous. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.
Troodon is a former wastebasket taxon and a potentially dubious genus of relatively small, bird-like theropod dinosaurs definitively known from the Campanian age of the Late Cretaceous period. It includes at least one species, Troodon formosus, known from Montana. Discovered in October 1855, T. formosus was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877. Several well-known troodontid specimens from the Dinosaur Park Formation in Alberta were once believed to be members of this genus. However, recent analyses in 2017 have found this genus to be undiagnostic and referred some of these specimens to the genus Stenonychosaurus some to the genus Latenivenatrix, and some to the genus Pectinodon. The genus name is Ancient Greek for "wounding tooth", referring to the teeth, which were different from those of most other theropods known at the time of their discovery. The teeth bear prominent, apically oriented serrations. These "wounding" serrations, however, are morphometrically more similar to those of herbivorous reptiles, and suggest a possibly omnivorous diet.
Mei is a genus of duck-sized troodontid dinosaur first unearthed by paleontologists from the Yixian Formation in Liaoning, China in 2004. Mei lived during the Early Cretaceous period. The binomial name of its only species, Mei long, means sleeping dragon.
Saurornithoides is a genus of troodontid maniraptoran dinosaur, which lived during the Late Cretaceous period. These creatures were predators, which could run fast on their hind legs and had excellent sight and hearing. The name is derived from the Greek stems saur~ (lizard), ornith~ (bird) and eides (form), referring to its bird-like skull.
Byronosaurus is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia.
Jinfengopteryx is a genus of maniraptoran dinosaur. It was found in the Qiaotou Member of the Huajiying Formation of Hebei Province, China, and is therefore of uncertain age. The Qiaotou Member may correlate with the more well-known Early Cretaceous Yixian Formation, and so probably dates to around 122 Ma ago.
Sinornithoides is a genus of troodontid theropod dinosaurs containing the single species Sinornithoides youngi. S. youngi lived during the Early Cretaceous. It measured approximately one meter long (3.3 ft). It lived in Inner Mongolia, China, and probably ate invertebrates and other small prey. They lived in what is now Mongolia, which was part of Laurasia.
Sinovenator is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period.
Sinusonasus is a genus of dinosaurs from the Early Cretaceous Period, recovered from the Yixian Formation. It lived in what is now the Liaoning Province of China. Sinusonasus was a theropod, specifically a troodontid dinosaur.
Xixiasaurus is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull, part of the lower jaw, and teeth, as well as a partial right forelimb.
Geminiraptor is a genus of troodontid theropod dinosaur that lived in North America during the Early Cretaceous period. Geminiraptor was a small, ground-dwelling bipedal carnivorous paravian. The type species of Geminiraptor is G. suarezarum.
Linhevenator is a genus of short-armed troodontid theropod dinosaur from the Late Cretaceous (Campanian) Bayan Mandahu Formation of Bayan Mandahu, Inner Mongolia, China.
Talos is an extinct genus of carnivorous bird-like theropod dinosaur, an advanced troodontid which lived during the late Cretaceous period in the geographic area that is now Utah, United States.
Philovenator is an extinct genus of troodontid paravian dinosaurs from the Wulansuhai Formation of Inner Mongolia, China. Its specific name honors Phillip J. Currie.
Jinfengopteryginae is a subfamily of bird-like theropod dinosaurs known from the Cretaceous of Eurasia. This group includes relatively few genera, with members discovered in 2005 but the name erected in 2012. Like other troodontids, this group of dinosaurs resided in the Paraves potentially close to the Avialae.
Gobivenator is an extinct genus of troodontid theropod dinosaur known from the late Campanian Djadokhta Formation of central Gobi Desert, Mongolia. It contains a single species, Gobivenator mongoliensis. G. mongoliensis is known from a single individual, which represents the most complete specimen of a Late Cretaceous troodontid currently known.
Beipiaognathus is a dubious genus of coelurosaurian theropod from the Early Cretaceous Yixian Formation of Liaoning, China. The type species is Beipiaognathus jii and it was named and described by Hu et al. in 2016.
Daliansaurus is a genus of small troodontid theropod dinosaur, measuring approximately 1 metre long, from the Early Cretaceous of China. It contains a single species, D. liaoningensis, named in 2017 by Shen and colleagues from a nearly complete skeleton preserved in three dimensions. Daliansaurus is unusual in possessing an enlarged claw on the fourth digit of the foot, in addition to the "sickle claw" found on the second digit of the feet of most paravians. It also has long metatarsal bones, and apparently possesses bird-like uncinate processes. In the Lujiatun Beds of the Yixian Formation, a volcanically-influenced region with a cold climate, Daliansaurus lived alongside its closest relatives - Sinovenator, Sinusonasus, and Mei, with which it forms the group Sinovenatorinae.
Liaoningvenator is a genus of troodontid theropod dinosaur from the Early Cretaceous of China. It contains a single species, L. curriei, named after paleontologist Phillip J. Currie in 2017 by Shen Cai-Zhi and colleagues from an articulated, nearly complete skeleton, one of the most complete troodontid specimens known. Shen and colleagues found indicative traits that placed Liaoningvenator within the Troodontidae. These traits included its numerous, small, and closely packed teeth, as well as the vertebrae towards the end of its tail having shallow grooves in place of neural spines on their top surfaces.
Papiliovenator is a genus of troodontid theropod dinosaur from the Bayan Mandahu Formation of Inner Mongolia, China. The type and only species is Papiliovenator neimengguensis.
