Subtiliolithus

Subtiliolithus
Temporal range: Late Cretaceous
Egg fossil classification Edit this classification
Basic shell type: Ornithoid
Morphotype: Ornithoid-ratite
Oofamily: Laevisoolithidae
Oogenus: Subtiliolithus
Mikhailov, 1991

Subtiliolithus is an oogenus of fossil egg from the Nemegt Formation of Mongolia and the Ohyamashimo Formation of Japan. The eggs are notable for a very thin eggshell. It contains three oospecies: S. hyogoensis, S. kachchhensis and S. microtuberculatus. They were originally classified as a distinct oofamily, Subtiliolithidae, but numerous similarities to Laevisoolithus have led to their reclassification as Laevisoolithid eggs. A complete skeleton of Nanantius valifanovi was found associated with Subtiliolithus eggshells, indicating that the oogenus represents eggs of enantiornithine birds.[1][2][3]


  1. ^ K. E. Mikhailov. 1991. Classification of fossil eggshells of amniotic vertebrates. Acta Palaeontologica Polonica 36(2):193-238
  2. ^ Carpenter, K. 1999. Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past). Indiana University Press, Bloomington, Indiana.
  3. ^ Kurochkin, E.N., S. Chatterjee, and K.E. Mikhailov. (2013) "An Embryonic Enantiornithine Bird and Associated Eggs from the Cretaceous of Mongolia." Paleontological Journal 47(11):1252-1269.