Preprismatoolithus

{{Short description|Trace fossil}}

{{Oobox

|fossil_range = {{fossil range|Late Jurassic}}

|image =

|taxon = Preprismatoolithus

|authority = Zelenitsky & Hills, 1996

}}

Preprismatoolithus is a Late Jurassic oogenus. The species P. coloradensis is described by John Foster as being "of the prismatic basic type," with subspherical eggs about 10 cm (4 inches) in diameter."Eggs," Foster (2007) page 125. This oospecies was first attributed to "hypsilophodontid" dinosaurs, although an initial lack of associated embryo material made confirming the egg-layer's identity impossible."Another Generation: The Eggs," Foster (2007) page 239. After a finding in PortugalRibeiro, V., Mateus O., Holwerda F., Araújo R., & Castanhinha R. (2013). Two new theropod egg sites from the Late Jurassic Lourinhã Formation, Portugal. Historical Biology. (ahead-of-print), 1-12. associated prismatic basic types with embryos, it now is known to be theropod.

Eggshell present in great abundance at the so-called "Young Egg Locality" which seems to have been a dinosaur nesting ground. Congeneric eggshell fossils are found at additional Colorado sites including the Fruita Paleontological Area, the Uravan Locality and Garden Park.