Undulatoolithusis anoogenusof Chinese fossildinosaur eggbelonging toElongatoolithidae.It is very similar toMacroolithus,but has different ornamentation. Like other elongatoolithids, it was probably laid byoviraptorosaurs.[1]
| Undulatoolithus Temporal range:
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Egg fossil classification
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| Basic shell type: | Ornithoid |
| Morphotype: | Ornithoid-ratite |
| Oofamily: | †Elongatoolithidae |
| Oogenus: | †Undulatoolithus Wanget al.,2013 |
| Oospecies | |
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Distribution
editUndulatoolithusis found in theZhoutian Formation,in thePingxiang BasinofJiangxi.It is dated to theUpper Cretaceous.[1]
History
editThe Pingxiang Basin, inJiangxi,was first excavated for fossils in2002.Several fossil eggs, egg clutches, and dinosaur bones were discovered, including those later described asUndulatoolithusin 2013 by Chinese paleontologistsWang Qiang,Zhao Zikui,Wang Xiaolin,Li Ning,andZou Songlin.The type and only known specimen ofUndulatoolithuswas the firstelongatoolithidegg clutch discovered in the Pingxiang basin.[1]
Description
editLike all elongatoolithids,Undulatoolithuseggs are elongated and asymmetrical, and have a two-layered eggshell (consisting of the cone layer and the columnar layer). The only knownUndulatoolithusspecimen is a nest consisting of five complete eggs and three partial eggs. The eggs are paired and arranged radially, similar to other elongatoolithids. They average about 20 centimetres (7.9 in) long and 8 centimetres (3.1 in) across. The eggshell is nearly 1.5 mm thick, including ornamentation.[1]
The boundary between the two eggshell layers inUndulatoolithusis gradual. The cone layer is relatively thin, ranging from one fourth to one eighth the width of the columnar layer.[1]
The most notable characteristic ofUndulatoolithusis the ornamentation on the surface of the eggshell. Like most elongatoolithids it is covered with nodes and ridges, but they are much more prominent than other oospecies and make up nearly half the total eggshell thickness.[1]
Paleobiology
editUndulatoolithushas not been associated with embryos or skeletal remains, so the identity of the egg-laying dinosaur is unknown.[1]However, all embryos or adult skeletons that have been associated with other elongatoolithids areoviraptorids.Like other elongatoolithids,Undulatoolithusprobably received intensive parental care.[2]
Parataxonomy
editUndulatoolithusis classified as within Elongatoolithidae. It is very similar toMacroolithus,but has much more prominent eggshell ornamentation.[1]
References
edit- ^abcdefghQ. Wang, Z. Zhao, X. Wang, N. Li, and S. Zou. (2013)A new form of Elongatoolithidae, Undulatoolithus pengi oogen. et oosp. nov. from Pingxiang, Jiangxi, China.Zootaxa3746(1):194-200
- ^Simon, D. J. (2014). "Giant Dinosaur (theropod) Eggs of the Oogenus Macroelongatoolithus (Elongatoolithidae) from Southeastern Idaho: Taxonomic, Paleobiogeographic, and Reproductive Implications."(Master's thesis,Montana State University,Bozeman). p. 19-22