Spheroolithidae

Spheroolithidae; Temporal range: Early – Late Cretaceous; ~136–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	Spheroolithus eggs from China
Egg fossil classification
Basic shell type:	†Dinosauroid-spherulitic
Oofamily:	†Spheroolithidae
Oogenera
	†Guegoolithus; †Spheroolithus; †Paraspheroolithus

Spheroolithidae is an oofamily of dinosaur eggs. It contains Guegoolithus, Spheroolithus, and Paraspheroolithus.^[1] Like modern birds, the eggshell membrane formed before the calcareous part of the shell.^[2]

References

^ Moreno-Azanza, M.; Canudo, J.I.; Gasca, J.M. (2014). "Spheroolithid eggshells in the Lower Cretaceous of Europe. Implications for eggshell evolution in ornithischian dinosaurs" (PDF). Cretaceous Research. 51: 75–87. doi:10.1016/j.cretres.2014.05.017.
^ Z.-K. Zhao. (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. Cambridge. pp. 184–203.