Pronunciation: SHE-shah-SOR-us
Meaning: Xixia (County) lizard
Author/s: Lu et al. (2010)
Synonyms: None known
First Discovery: Henan, China
Discovery Chart Position: #725
Xixiasaurus henanensis
Discovered in Xixia County, hence the name, Xixiasaurus is a troodontid — the theropod dinosaurs that are closely related to both dromaeosaurids and true birds. With their modest build, second toe sickle claws, large brain relative to body size, and keen senses, they're all pretty similar on the face of it. However, a closer look at their faces reveals a shed-load of species-defining features, which is fortunate, because the face of Xiaxiasaurus, along with the rest of the skull and a partial arm, is all the remains we have.
The teeth of Xixiasaurus lack serrations which sets it apart from Sinosonasus, Sinovenator, and most other troodontids beginning with "S". And based on size, skull shape and tooth design Mei long and Anchiornis are different again. Despite having a lower tooth count (22 to 30) Xixiasaurus seems closest to Byronosaurus amongst troodontids, and also Urbacodon based on what we know of its lower jaw, and the three may form an exclusive clade of Late Cretaceous Asian troodontids that don't hail from either the Gobi Dessert or northern China.
Some paleontologists suspect that the loss of serrations on troodontid teeth could represent a shift in diet from carnivorous to omnivorous or even herbivorous.
The teeth of Xixiasaurus lack serrations which sets it apart from Sinosonasus, Sinovenator, and most other troodontids beginning with "S". And based on size, skull shape and tooth design Mei long and Anchiornis are different again. Despite having a lower tooth count (22 to 30) Xixiasaurus seems closest to Byronosaurus amongst troodontids, and also Urbacodon based on what we know of its lower jaw, and the three may form an exclusive clade of Late Cretaceous Asian troodontids that don't hail from either the Gobi Dessert or northern China.
Some paleontologists suspect that the loss of serrations on troodontid teeth could represent a shift in diet from carnivorous to omnivorous or even herbivorous.
(Xixia lizard from Henan)Etymology
Xixiasaurus is derived from "Xixia" (for Xixia County) and the Greek "sauros" (lizard).
The species epithet, henanensis, means "from Henan" in Latin.
Discovery
The first remains of Xixiasaurus were discovered in the Majiacun Formation at Songgou Village, Zhangying of Wuliqiao Town, north−east region of Xixia County, Henan, China.
The holotype (41HIII-0201) includes a partial skull, arm and hand bones.
