''Prismatoolithus'' is an oogenus of dinosaur egg from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

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Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by t ...

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

) and possibly also the earliest Paleocene. They likely belonged to troodontidsMateus, I, H Mateus, MT Antunes, O Mateus, P Taquet, V Ribeiro, G Manuppella. 1998. Upper Jurassic theropod dinosaur embryos from Lourinhã (Portugal). Memórias da Academia das Ciências de Lisboa 37, 101-110

References

Dinosaur reproduction Egg fossils Fossils of Canada Paleontology in Alberta Fossils of China Fossils of France Fossils of Japan Fossils of Mexico Fossils of Morocco Fossils of Spain Tremp Formation Fossils of the United States Paleontology in Montana Paleontology in New Mexico Paleontology in Utah Milk River Formation Fossil parataxa described in 1993 {{eggshell-stub