Dictyoolithus
Dictyoolithus is an oogenus of dinosaur egg from the Cretaceous of China. It is notable for having over five superimposed layers of eggshell units. Possibly, it was laid by megalosauroid dinosaurs. Distribution. "Dictyoolithus" is known from Hongpo, a town in Xixia County, Henan. This is in the Lower Cretaceous Sigou Formation. It has also been discovered in Lishui, Zhejiang, in the Upper Cretaceous Chichengshan Formation. History. "Dictyoolithus" was first discovered and described in 1994 by Chinese paleontologist and pioneer of fossil eggshell classification, Zhao Zikui. He named two oopsecies: "D. hongpoensis" and "D. neixiangensis" (now "Protodictyoolithus neixiangensis"). However, since  excavations were still going on at the time, his description was brief. In 2004, a third oospecies was named, "D. jiangi", followed by a fourth, "D. gonzhulingensis" in 2006. However, in 2013 Chinese paleontologists Wang Qiang, Zhao Zikui, Wang Xiaolin, Zhang Shukang, and Jiang Yan'gen did a reanalysis of the entire oofamily Dictyoolithidae, and split the oogenus "Dictyoolithus" into two, classifying ""D." neixiangensis" and ""D." jiangi" within a new oogenus: "Protodictyoolithus". Furthermore, they moved ""D." gonzhulingensis" into an entirely different oofamily and oogenus, reclassifying it as a member of "Similifaveoloolithus". Description. "Dictyoolithus" eggs are roughly spherical and measure from in  diameter. Their eggshell is between 2.5 and 2.8 mm thick. The surface ornamentation is smooth with a grainy texture, or has very low rounded nodes. The eggshell is notable for being composed of more than five superimposed layers of eggshell units. In some specimens, found at Lishui, no superimposed layers of eggshells were found. However, it is not certain that these specimens in fact represent "Dictyoolithus". The eggshell units have a reticulate organization. Paleobiology. Since no embryos or adult remains have been found with "Dictyoolithus" eggs, it is uncertain what kind of dinosaur laid them. A cladistic analysis in 2010  by Jin "et al." found "Dictyoolithus" to be basal theropod eggs. Similarly, Sellés and Galobart in 2015 found "Dictyoolithus" to be basal theropods, and considered it to be the eggs of megalosauroids. Unlike many dinosaur eggs, the calcareous and membranous parts of "Dictyoolithus" eggshells probably formed simultaneously in the oviduct, as in the modern tuatara. Parataxonomy. "Dictyoolithus" is classified in the oofamily Dictyoolithidae, alongside "Protodictyoolithus" and "Paradictyoolithus". It contains only a single oospecies: "D. hongpoensis". Mikhailov (1997) suggested that it may actually be a dendroolithid.