摘要: In 1958, a special type of dinosaur egg was discovered in Zhaotuan, Laiyang,
Shandong Province, China. Although only a large eggshell fragment was collected, its extremely
large thickness indicated that the eggshell fragment represented a new ootaxon. In previous
studies, it was named Spheroolithus megadermus and assigned to the oogenus Spheroolithus
under the oofamily of the Spheroolithidae based on the microstructure in radial view. However, a
comparative study of the microstructure in tangential views between the large eggshell fragment
from Laiyang and the recently reported Multifissoolithus from Zhejiang Province, China and
Yamaguchi, Japan revealed that all of them have roughly paralleled and wavy clefts. Therefore,
this study reassigned the large eggshell fragment from Laiyang to Multifissoolithus of the
Dongyangoolithidae and discussed its unique compact layer near the eggshell’s inner surface, as
well as the chronological and spatial distribution of dongyangoolithid eggs. The reassignment
of the holotype of Spheroolithus megadermus also indicates that the referred specimen of
Spheroolithus megadermus from Changtu, Liaoning Province becomes the holotype of a new
oospecies Spheroolithus quantouensis.