Kayrasaurus
From Kayra, the god of creation in Turkic Shamanism and father of Erlik, the god of death, alluding to its phylogenetic connection to Erlikosaurus; and Greek 'sauros' (lizard).
Kayrasaurus is an extinct genus of therizinosaurian theropod dinosaur known from the Early Cretaceous (Barremian–Aptian ages) Yixian Formation of China. The genus contains a single species, Kayrasaurus changliensis, named in 2026 based on a nearly complete skeleton including the skull. This specimen is largely articulated, but very flattened into nearly two dimensions. The legs and most of the pelvis are unknown. With a length of 3.6 meters (12 ft) and an estimated weight of 117–274 kilograms (258–604 lb), Kayrasaurus is the largest therizinosaur known from the Jehol Biota. Like other therizinosaurs, the front of its jaws were toothless. It is unique in the small, closely packed teeth in the rest of the upper and lower jaws, bearing more teeth in the mandible than any other therizinosaur. The vertebrae in the neck are notably elongated, and the claws on the hand are large and strongly curved. Kayrasaurus is closely related to the contemporary Beipiaosaurus and Jianchangosaurus, both of which are also known from the Yixian Formation.
Diagnosis
- Nasal extends posteriorly to the level of the mid-orbit.
- Anterior end of the nasal bears two processes.
- External mandibular fenestra sub-triangular in outline.
- Proximal articular end of manual phalanx II-1 wider than high.
- Ungual of manual digit IV bears a dorsally extended 'lip' on its proximal articular surface.
Species
Kayrasaurus changliensis Liao et al., 2026
Type species
From Changli, a historical place name from the Three Kingdoms period, referring to the provenance of the fossil.
- Holotype
- IVPP V18597 , Institute of Vertebrate Paleontology and Paleoanthropology
- Material
- Nearly complete skeleton missing the hind limbs, including a largely complete skull with mandible, a semi-articulated vertebral column lacking the distalmost caudals, and forelimbs lacking some metacarpals and carpals.
- Notes
- The describing paper's Holotype paragraph and abstract give the number as IVPP V 18597, while its description, figures and tables give IVPP V 18957.
- Horizon
- Yixian Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
- Locality
- Dabangou village, Sihetun Area, Liaoning, China
References
- Liao, C. C.; Freimuth, W. J.; Zanno, L. E.; Xu, X. (2026). A new therizinosaur from the Early Cretaceous Jehol Biota and ecomorphological patterns among early therizinosaurians. Journal of Systematic Palaeontology 24(2): 2710287. Informa UK Limited. doi:10.1080/14772019.2026.2710287 liao2026a