Prismatoolithidae Hirsch, 1994

Moreno-Azanza, Miguel, Canudo, José I. & Gasca, José M., 2014, Unusual theropod eggshells from the Early Cretaceous Blesa Formation of the Iberian Range, Spain, Acta Palaeontologica Polonica 59 (4), pp. 843-854 : 845

Oofamily Prismatoolithidae Hirsch, 1994

Type oogenus: Preprismatoolithus Hirsch, 1994 ; Morrison Formation , upper part of Salt Wash Member ( Upper Jurassic ); Young locality, Delta County, Colorado, USA .

Emended diagnosis.—Eggshells with at least two layers: a lower mammillary layer with radial-tabular ultrastructure and an upper prismatic layer with prisms with tabular ultrastructure. Transition between mammillary and prismatic lay- er is gradual.A third external layer with tabular ultrastructure may be present. Angusticanaliculate or obliquicanaliculate pore system; outer surface smooth, undulating or sculptured. Eggshell thickness 300–1220 μm; eggs elongate, ovoidal- or ellipsoidal-shaped; EL (elongation index): ratio of the long diameter of an egg to its short diameter = 1.8–2.7.