''Parvoolithus'' is an

oogenus Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

fossil egg Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...

s from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian s ...

Barun Goyot Formation The Barun Goyot Formation (also known as Baruungoyot Formation or West Goyot Formation) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Pro ...

. They are known from a single small, smooth egg, which cannot be assigned to any known oofamily. It is very similar to the eggs of modern birds in many aspects; in fact, a

cladistic analysis Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived chara ...

by Zelenitsky and Therrien found it to be a sister taxon to the guinea fowl (genus '' Numida''), indicating that they represent the eggs of birds, rather than a non-avialan

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...

.Zelenitsky, D.K. and Therrien, F. (2008). Phylogenetic analysis of reproductive traits of maniraptoran theropods and its implications for egg parataxonomy. ''Palaeontology'', 51(4): 807–816

References

Bibliography

* K. E. Mikhailov. 1996. New genera of fossil eggs from the Upper Cretaceous of Mongolia. Paleontological Journal 30(2):246-248 Egg fossils Late Cretaceous animals of Asia Campanian life Cretaceous Mongolia Fossils of Mongolia Barun Goyot Formation Fossil parataxa described in 1996 {{eggshell-stub