The Xixia Basin lies in Henan Province, China, to the east of the Qinling Mountains of southern Shaanxi Province, and extends roughly 100 km east-to-west, covering an area of about 518 km². Within this basin a series of Upper Cretaceous fluvial deposits overlie a Devonian basement. These deposits have been divided into three formations, the middle one of which, known as the Zhaoying (or sometimes Majiacun) Formation, comprises a 2120 m thick sequence beginning with motley argillaceous siltstones, sandstones and mudstones at the base, and grading into an upper layer comprising reddish mudstones and sandstones. This sequence, considered to have been laid down in a fluvio-lacustrine basin in an area with a generally arid climate, is noted for its production of preserved Dinosaur eggs, with at least seven described oospecies (because eggs are a record of a part of the life-cycle of an animal, can seldom be related to a species defined from body fossils, they are described under a parataxonomic system as oospecies, which are then organised into oogenera and oofamilies) from the Zhaoying and underlying Zoumagang (or Gaogou) formation, as well as ichnofossils (trace fossils), Dinosaur bones, Turtle eggs, and fossil Bivalves, Gastropods, Ostracods, Spinicaudatans, and Plants.
In a paper published in the journal Acta Palaeontologica Polonica on 17 December 2025, Qing He and Shutong Li of the School of Resources and Environmental Engineering at Anhui University, Shukang Zhang of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Yifan Huang of the Prevention and Control Center for Geological Disasters at the Henan Geological Bureau, Xiqiang Cao of the Henan Scientific Academy of Land and Resources, and Hongqing Li and Mengyuan Zhu, also of the School of Resources and Environmental Engineering at Anhui University, describe a new oospecies of Dinosaur eggs from the Zhaoying Formation of Xixia County.
The new species is placed in the oogenus Parafaveoloolithus, and given the specific name 'xixiaensis' meaning 'from Xixia'. The species is described from a clutch of 13 subspherical eggs arranged in a radial pattern. The individual eggs are 123.3–142.6 mm by 97.2–127.2 mm, with shells 123.3–142.6 mm and 97.2–127.2 mm thick. The shells have a single structural layer with no visible growth lines and a honeycomb structure with straight pore canals.
The oogenus Parafaveoloolithus belongs to the oofamily Faveoloolithidae, which includes six genera from the Late Cretaceous of China, Mongolia, and South Korea. No fossil eggs from outside East Asia have been assigned to the oofamily (some 'Titanosaur eggs' from the Late Cretaceous of Argentina have been suggested as possible members of the family, but this is doubtful), suggesting that the egg-layers had a limited geographical distribution, although they are found in a variety of different palaeoenvironments.
Very few eggs belonging to the Faveoloolithidae have been found in clutches to date, and Parafaveoloolithus xixiaensis is probably the best known example to date. The radial pattern in which the eggs are arranged suggests that this is a true representation of how they were deposited, rather than a result of transportation and redeposition. He et al. suggest that the pattern and porosity of the eggs implies the female Dinosaur would have deposited the eggs in a roughly circular arrangement, before covering them over with sand - something which would also have aided there preservation.
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