| Xinjiangovenator | |
|---|---|
 | |
| Holotype bones alongsidePhaedrolosaurus lectotype tooth | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avetheropoda |
| Clade: | Coelurosauria |
| Genus: | †Xinjiangovenator Rauhut &Xu, 2005 |
| Species: | †X. parvus |
| Binomial name | |
| †Xinjiangovenator parvus Rauhut & Xu, 2005 | |
Xinjiangovenator (meaning "Xinjiang hunter") is agenus ofcoelurosauriandinosaurs,[1] possibly part of the groupManiraptora, which lived in theLianmuqin Formation of theTugulu Group of China, dated to theEarly Cretaceousperiod, sometime between theValanginian andAlbian stages.[2]
The remains ofXinjiangovenator were found in theLianmuqin Formation ofWuerho,Xinjiang,China, and were first described byDong Zhiming in 1973. The genus is based on a single specimen, an articulated partial right lower leg, containing thetibia, three pieces of thefibula, thecalcaneum and theastragalus, as well as two fused pedal phalanges. This specimen,IVPP V4024-2, is theholotype of the genus.[2]
The holotype was originally thought to be another specimen ofPhaedrolosaurus.[3] However,Phaedrolosaurus is based only on a non-diagnostic tooth, so the hindlimb bones were given their own genus byOliver Rauhut andXu Xing in 2005. Thetype species isXinjiangovenator parvus. The generic name is derived from the autonomous region of Xinjiang andLatinvenator, "hunter". Thespecific nameparvus means "small" in Latin.[2]
The lower leg (tibia plus ankle bones) has a length of 312 millimeters (12.3 inches). Gregory S. Paul estimated in 2010 thatXinjiangovenator individuals had a length of 3 meters and a mass of 70 kg.[4] Rauhut & Xu (2005) established twoautapomorphies (unique derived traits) that could be used to characterizeXinjiangovenator. First, thelateral condyle (outer ankle joint) at the lower end of the tibia extends further backwards than the outer edge of the portion of the tibia near the knee. Secondly, the proximal part of the fibula (near the knee) has a longitudinal groove along its front edge.[2]
Rauhut & Xu (2005) originally placedXinjiangovenator within the coelurosaur subgroupManiraptora using a phylogenetic analysis. It was considered to be more closely related toparavians such asdromaeosaurids andbirds, rather thanoviraptorosaurians andtherizinosaurs. This placement was justified by the presence of a tall and wide ascending process of the astragalus bone. In addition, the fibular condyle of the femur expanded backwards and the fibula tapered drastically towards the ankle. These characteristics were also found to be present in the coelurosaurBagaraatan, and Rauhut & Xu (2005) suggested thatXinjiangovenator andBagaraatan weresister taxa.[2]
The 2010 description ofZuolong byJonah Choiniere,James M. Clark,Catherine Forster, & Xu Xing found a different position forXinjiangovenator in their phylogenetic analysis. Due to its fragmentary nature,Xinjiangovenator was found to have an unstable position within Coelurosauria. Some, but not all, of the phylogenetic trees foundXinjiangovenator as the sister taxon toOrnitholestes based on the proximal part of the tibia being just as wide along its front edge as its rear edge. WhenXinjiangovenator was removed from the analysis,Ornitholestes was found to be a basal maniraptoran.[1]
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