Triprismatoolithus
| Sankofa Temporal range:
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Egg fossil classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Superfamily: | †Alvarezsauroidea |
| Family: | †Alvarezsauridae |
| Oofamily: | †Arriagadoolithidae |
| Oogenus: | †Triprismatoolithus |
| Oospecies | |
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Triprismatoolithus is an oogenus of dinosaur egg native to Teton County, Montana.[1]
Description
The type specimen of Triprismatoolithus is a complete egg measuring 30 mm by 75 mm, but several other incomplete eggs and eggshell fragments are known. The eggs were paired, similar to Continuoolithus. The eggshell is between ranges from 525 to 850 μm thick.[1]
Triprismatoolithus is notable for having three structural layers,[1] similar to birds and unlike most other non-avian dinosaur eggs.[2] The second layer, known as the prismatic layer, is made up of closely packed calcite crystals, and exhibits irregular squamatic texture.[1][3] It is five times thicker than the mammillary layer.[1]
The surface of the eggshell of Triprismatoolithus is covered with low, rounded tubercles, similar to Arriagadoolithus.[3][1]
References
- ^ a b c d e f Jackson, Frankie; Varricchio, David (2010). "Fossil eggs and eggshell from the lowermost Two Medicine Formation of western Montana, Sevenmile Hill locality". Journal of Vertebrate Paleontology. 30 (4): 1142–1156. doi:10.1111/j.1475-4983.2011.01114.x.
- ^ Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. Bray. (2012). "Fossil eggshell: Fragments from the past" UCMP's online fossil egg exhibit.
- ^ a b F. L. Agnolin, J. E. Powell, F. E. Novas and M. Kundrát. 2012. "New alvarezsaurid (Dinosauria, Theropoda) from uppermost Cretaceous of north-western Patagonia with associated eggs." Cretaceous Research 35(1):33-56