Shixingoolithus eggs are nearly spherical, and about 12 cm in diameter, with a shell thickness of 2.3–2.6 mm. The shell is made up of tall, prismatic units, and has narrow, irregular pore canals. Its cone layer (mammillae) is approximately a fourth of the shell thickness.[3][4]
Shixingoolithus was initially described as a member of the Spheroolithidae on the basis of its spherical shape, and similarities to other spheroolithid eggs.[7][3] In 2012, Wang et al. classified Shixingoolithus in a new oofamily, Stalicoolithidae, alongside Stalicoolithus and Coralloidoolithus, because of the secondary eggshell units found in its pore canals.[9] However, these secondary shell units may in fact simply be taphonomic artifacts. It has also been speculated to in fact be a dendroolithid, but a more complete description must be made before its classification can be resolved.[6]
^Z. Zhao, J. Ye, H. Li, Z. Zhao, and Z. Yan. 1991. Extinction of the dinosaurs across the Cretaceous-Tertiary boundary in Nanxiong Basin, Guangdong Province. Vertebrata PalAsiatica 29(1):1-20
^ abcCarpenter, K. 1999. Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past). Indiana University Press, Bloomington, Indiana.
^Zhao, Z.K. (1994). "Dinosaur eggs in China: On the structure and evolution of eggshells." In K. Carpenter, K. F. Hirsch, and J. R. Horner (eds.), Dinosaur Eggs and Babies, Cambridge University Press, Cambridge. In K. Carpenter, K. F. Hirsch, and J. R. Horner (eds.), Dinosaur Eggs and Babies, Cambridge University Press, Cambridge 184–203
^ abMoreno-Azanza, M., J.I. Canudo, and J.M. Gasca. (2014). "Spheroolithid eggshells in the Lower Cretaceous of Europe. Implications for eggshell evolution in ornithischian dinosaurs." Cretaceous Research 51:75-87.
^Zhao, Z.-k., X. Mao, Z. Chai, G. Yang, P. Kong, M. Ebihara, and Z.-h. Zhao. (2002). "A possible causal relationship between extinction of dinosaurs and K/T iridium enrichment in the Nanxiong Basin, South China: evidence from dinosaur eggshells. Palaeogeography, Palaeoclimatology, Palaeoecology 178:1-17.