page_title: Sinovenator
section_title: Description
hierarchical_section_title: Sinovenator / Description
caption_attribution_description: Skull and mandibles of Sinovenator PMOL-AD00102 in left lateral view. (A) photograph; (B) CT-rendered image. Study sites: an, angular; ax, axis; co, coronoid; cp, cultriform process; cr, cervical ribs; d, dentary; e, epipterygoid; f, frontal; j, jugal; l, lacrimal; ls, laterosphenoid; m, maxilla; n, nasal; p, parietal; pl, palatine; po, postorbital; pop, paroccipital process; pra, prearticular; q, quadrate; qj, quadratojugal; sd, supradentary; sp, splenial; sq, squamosal; su, surangular; v, vomer.
context_page_description: Sinovenator is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period.
context_section_description: Sinovenator is a troodontid, a group of small, bird-like, gracile maniraptorans. All troodontids have many unique features of the skull, such as closely spaced teeth in the lower jaw, and large numbers of teeth. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephalization quotients, meaning they were behaviourally advanced and had keen senses. The holotype individual of Sinovenator was about the size of a chicken, less than a metre long. In 2010, Gregory S. Paul estimated the weight of a one metre long individual at 2.5 kilogrammes. However, the holotype and paratype are subadults; specimens are known with about twice their length. This makes it one of the larger species of troodontids in the ecosystem of the Yixian Formation, the formation where it was found.
  In the original description some distinguishing traits or autapomorphies were established. The front edge of the antorbital fenestra, the large skull opening in front of the eye socket, is straight and vertically oriented. The frontal bone shows a vertical ridge touching the lacrimal bone. The surangular in the lower jaw has a T-shaped cross-section. The shinbone has a vertical ridge on the upper outer side, the crista cnemialis, touching a lower vertical ridge, the crista fibularis.
   
  There is a number of other notable traits. The upper branch of the praemaxilla excludes the maxilla from the nostril. The premaxillary teeth lack denticles; those on the maxillary teeth are small. The maxillary tooth row is positioned at some distance from the jaw rim. A fenestra promaxillaris is present. The branch of the jugal towards the postorbital is long, slender and inclined to the rear. The foramen magnum is much larger than the occipital condyle. The braincase lacks a recessus suboticus and a crista otosphenoidalis. The rear of the pterygoid has a secondary, rod-like, process. The front dentary teeth are closely packed. The rear of the surangular is extraordinarily deep.
  Five sacrals are present, those of the middle being clearly larger. The ilium is relatively small. The ischium is bird-like: small with a low obturator process and processes on the upper and lower rear edge. The shinbone is wide at the top and has a roughly rectangular lower joint surface. The fourth metatarsal is not strongly developed but the second metatarsal is small. The third metatarsal is pinched at the top but still visible at the upper front of the metatarsus, conforming to the subarctometatarsal condition.
caption: Photo and CT scan of skull PMOL-AD00102
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