''Medioolithus'' 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 ...

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

laid by a

paleognath Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Pala ...

.Kohring, R., & Hirsch, K. F. (1996). "Crocodilian and avian eggshells from the Middle Eocene of the Geiseltal, Eastern Germany." ''Journal of Vertebrate Paleontology'', 16(1), 67-80.

Description

''Medioolithus'' is known several eggshell fragments, and one complete, spherical egg. ''M. geiseltalensis'' is very similar to modern ratite eggs, for example those of

ostriches Ostriches are large flightless birds. Two living species are recognised, the common ostrich, native to large parts of sub-Saharan Africa, and the Somali ostrich, native to the Horn of Africa. They are the heaviest and largest living birds, w ...

, rheas, and

cassowaries Cassowaries (; Biak language, Biak: ''man suar'' ; ; Papuan_languages, Papuan: ''kasu weri'' ) are flightless birds of the genus ''Casuarius'', in the order Casuariiformes. They are classified as ratites, flightless birds without a keel (bird a ...

. At in diameter, however, it is smaller than the eggs of any of these birds, being more similar in size to the egg of a

kiwi Kiwi most commonly refers to: * Kiwi (bird), a flightless bird native to New Zealand * Kiwi (nickname), an informal name for New Zealanders * Kiwifruit, an edible hairy fruit with many seeds * Kiwi dollar or New Zealand dollar, a unit of curren ...

References

{{Taxonbar, from=Q25094942 Egg fossils Fossil parataxa described in 1996