| Kaijiangosaurus | |
|---|---|
 | |
| Speculative life restoration based on other theropods | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Tetanurae |
| Genus: | †Kaijiangosaurus He, 1984 |
| Type species | |
| †Kaijiangosaurus lini He, 1984 | |
Kaijiangosaurus (meaning "Kaijiang lizard") is agenus of carnivoroustetanurantheropoddinosaur from the MiddleJurassic ofChina. In 1984He Xinlu named and described thetype speciesKaijiangosaurus lini. The generic name refers to the River (jiang)Kai. Thespecific name honours the paleontologistLin Wenqiu.[1]
Theholotype specimen, CCG 20020, was discovered before 1984 inSichuan, in a layer of theXiashaximiao Formation dating from theBathonian-Callovian. The specimen consists of a fragmentary skeleton lacking the skull. The holotype proper contains the intercentrum of the atlas and the third to ninth neck vertebrae. Other elements have been designated as aparatype, including fragmentary remains of the skull, nine teeth, elements of the pectoral girdle, a forelimb, and a hindlimb. Another paratype is the thighbone of a probably smaller individual.[1] Holtzet al. (2004) mentioned much more complete specimens, but they are undescribed.[2] There have been doubts about the validity ofKaijiangosaurus. It has been suggested that it should be regarded as a synonym ofGasosaurus, which was found in the same strata asKaijiangosaurus, theLower Shaximiao Formation, or ofXuanhanosaurus.[3][4]
Kaijiangosaurus had a length of about five metres. He mentioned some diagnostic traits. The jugal is straight-edged at the front, deeper at the rear. The teeth are of the megalosaurid type. Their leading edge has only few serrations, near the tip. The cervicals are short, wide and narrow in the middle. The front cervicals have spines with a concave trailing edge. These neck vertebrae are about as wide as they are long; their spines are low and wide. The centra of the rear cervical are concave at their back; their spines are long and narrow. The dorsals are platycoelous and have smooth sides lacking pleurocoels. The front tail vertebrae are also platycoelous, with a flat front and concave rear; the rear caudals are amphicoelous. Thetail vertebrae have flat undersides without a midline groove. The scapula is rather straight with only a relative constriction at the lower end and a light expansion at the upper end. Thecoracoid is oval and has a thick ridge at the upper outer side. With the humerus, the deltopectoral crest is triangular; the shaft has an oval cross-section. Theulna is short and expanded at both ends. The three claws of the hand are strongly curved. Both ends of the thighbone are expanded; the neck is somewhat directed to the rear. The lesser trochanter is low, with a triangular profile. The middle metatarsals are not fused, nor is the third metatarsal constricted at the top.[1][5]
He originally placedKaijiangosaurus in theMegalosauridae.[1] Modern analysis suggests it is a basal member of theTetanurae, or perhaps theAverostra.[6] Due to the fragmentary nature of the remains, it is uncertain what type of tetanuran theropod it is, though it may be a primitivecarnosaur.[7]
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