''Paradictyoolithus'' is an oogenus of dictyoolithid dinosaur egg from the

Zhejiang Province Zhejiang ( or , ; , also romanized as Chekiang) is an eastern, coastal province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable cities include Ningbo and Wenzhou. Zhejiang is bordered by Jiangs ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. They are nearly spherical eggs, measuring up to in diameter, and have a thin eggshell. Their shells are made up of three or four superimposed layers of eggshell units. The two known oospecies are distinguished mainly by their pore structure.

Distribution

Both ''Paradictyoolithus'' oospecies are from the Chichengshan Formation in Tiantai County, Zhejiang, China. This formation was determined to be 91 to 94 million years old (early Upper Cretaceous) by Uranium–lead dating.Huaiyu He, Xiaolin Wang, Qiang Wang, Shunxing Jiang, Xin Cheng, Jialiang Zhang, Zhonghe Zhou, Zikui Zhao, Yangen Jiang, Fangming Yu, Chenglong Deng, Jinhui Yang, Rixiang Zhu (2013).
SIMS zircon U–Pb dating of the Late Cretaceous dinosaur egg-bearing red deposits in the Tiantai Basin, southeastern China.
''Journal of Asian Earth Sciences,'' 62, 654-661.

Discovery

Prior to 2013, descriptions of dictyoolithids were brief due to the scarcity of material. However, in 2013 the Chinese paleontologists Wang Qiang, Zhao Zi-Kui, Wang Xiao-Lin, Zhang Shu-Kang from the Chinese Academy of Sciences working together with Jiang Yan-Gen from the Tiantai Bureau of Land and Resources of Zhejiang Province, described several new dictyoolithid specimens, including both oospecies of ''Paradictyoolithus''.

Description

''Paradictyoolithus'' eggs are roughly spherical, measuring in diameter. Their eggshell is thin, measuring only 1.8 to 2.2 mm thick (compared to 2.5 to 2.8 mm in its close relative, '' Dictyoolithus''). The shell consists of three or four layers of superimposed eggshell units. A radial cross section of the eggshell reveals the net-like (or reticulate) arrangement of the eggshell units, typical of dictyoolithid eggs. The shell units are slender and irregularly shaped. ''Paradictyoolithus'' contains two oospecies: ''P. zhuangqianensis'' and ''P. xiaxishanensis''. The two oospecies are primarily distinguished by their pore structure. ''P. zhuangqianensis'' has pores which all connect to each other in irregular patterns; the walls of the pores are separated into disconnected blocks. ''P. xiaxishanensis'', on the other hand, has well-separated pore canals which look like a honeycomb in cross-section. Also, ''P. zhuangqianensis'' is slightly larger than ''P. xiaxishanensis'', but has a thinner shell. A fossilized

egg clutch __NOTOC__ A clutch of eggs is the group of eggs produced by birds, amphibians, or reptiles, often at a single time, particularly those laid in a nest. In birds, destruction of a clutch by predators (or removal by humans, for example the Califor ...

containing six eggs and an egg impression reveals that ''P. xiaxishanensis'' eggs were arranged irregularly in their nest. The only known clutch of ''P. zhuangqiensis'' is not well enough preserved to determine how the nest was organized.

References

{{Taxonbar, from=Q22285364 Fossil parataxa described in 2013 Egg fossils Dinosaur reproduction Cretaceous dinosaurs of Asia