Restudy of the original and new materials of Stromatoolithus pinglingensis and discussion on some Spheroolithidae eggs

ABSTRACT

In this study, we restudied a rarely known oospecies from China, Stromatoolithus pinglingensis. Original materials from type locality Nanxiong, Guangdong Province as well as recently recovered materials from Shanyang, Shaanxi Province and Laiyang, Shandong Province are compared in this study. After detailed study about general and micro-structure of these eggshells, we are sure that this ootaxon cannot be placed within Spheroolithidae or any other oofamilies, though new oofamily cannot be erected due to lack of complete specimen. In the meantime, we reviewed some Spheroolithidae eggs from Asia, North America, and Europe. We propose that the Mongolia oospecies Spheroolithus maiasauroides is a synonym of Stromatoolithus pinglingensis. Eggs of Maiasaura, Spheroolithus albertensis from North America and Spheroolithus europaeus from Spain should be reassigned to Stromatoolithus. The Lower Cretaceous oospecies Guegoolithus turolensis from Spain should also be considered as ootaxon with close relationship to Stromatoolithus but not Spheroolithidae. The geographic distribution of Spheroolithidae may not be so wide as former researchers thought, and the producer of Spheroolithidae is back to unknown. The oogenus Stromatoolithus is associated with hadrosaurs, and may restrict to Hadrosauridae.

KEYWORDS:

• Stromatoolithus
• Spheroolithidae
• Late Cretaceous
• China
• dinosaur egg
• parataxonomy

Acknowledgments

The authors would like to thank Zhao Zikui and Zhang Shukang from IVPP (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China) for useful advice and information. We thank anonymous reviewers for their constructive comments on the manuscript. Jin Xun from IVPP helped with the SEM photography. This work was supported by the National Natural Science Foundation of China (41672012,41688103), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB26000000), and the Laiyang Government Cooperation Dinosaur Project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [41672012,41688103]; The Strategic Priority Research Program of the Chinese Academy of Sciences [XDB26000000]; Laiyang Government Cooperation Dinosaur Project.