Open Paleo

Bayannurosaurus

Xu et al., 2018 BAY-a-NOOR-oh-SOR-us

Named for the Bayin-Gobi (Bayannur) region of China where the fossils were found, combined with Greek 'sauros' meaning 'lizard'.

121.4–113.2 million years ago Aptian, Early Cretaceous
Early Cretaceous stages

Bayannurosaurus is a non-hadrosauriform ankylopollexian ornithopod described in 2018 by Xu Xing. It lived during the early Aptian period, being found in the Bayin-Gobi Formation of China. The genus includes the type species Bayannurosaurus perfectus. A phylogenetic analysis of Bayannurosaurus indicates that it is more derived than Hypselospinus, yet less derived than Ouranosaurus and just outside of the Hadrosauriformes. It was a large iguanodontian, measuring up to 9 meters (30 ft) in total body length. The genus name Bayannurosaurus comes from Bayannur, the area where it was found, while the species name perfectus comes from the "perfect" preservation of the holotype specimen (IMMNH PV00001).

Diagnosis

  1. Jugal bearing a dorsally directed, strap-like posterodorsal process
  2. Iliac preacetabular process horizontally oriented
  3. Large, subconical ungual of manual digit I with a length/width ratio close to 1.0
  4. Posterior-most caudals with procoelous centra showing trapezoidal dorsal outlines; last three caudals fully fused
  5. Markedly bifurcated anterior maxilla with an elevated anterodorsal process
  6. Denticulate anteromedial premaxillary oral margin with a shallow peripheral groove

Species

Bayannurosaurus perfectus Xu et al., 2018

Type species

Named for the 'perfect' preservation of the holotype skeleton (IMMNH PV00001).

Holotype
IMMNH PV00001 , Inner Mongolia Museum
Material
Nearly complete, semi-articulated skeleton including the entire caudal series
Horizon
Bayin-Gobi Formation, Aptian, Early Cretaceous , 121.4–113.2 million years ago
Locality
Chulumiao, Inner Mongolia, China

References

  1. Xu, X.; Tan, Q.; Gao, Y.; Bao, Z.; Yin, Z.; Guo, B.; Wang, J.; Tan, L.; Zhang, Y.; Xing, H. (2018). A large-sized basal ankylopollexian from East Asia, shedding light on early biogeographic history of Iguanodontia. Science Bulletin 63(9): 556-563. Elsevier BV. doi:10.1016/j.scib.2018.03.016 xu2018a