Ageroolithusis anoogenusofdinosaur egg.It may have been laid by atheropod.[1]
| Ageroolithus Temporal range:
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|---|---|
Egg fossil classification
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| Basic shell type: | Ornithoid |
| Morphotype: | Ornithoid-ratite |
| Oofamily: | incertae sedis |
| Oogenus: | †Ageroolithus Vianey-Liaud and López-Martínez, 1997 |
| Oospecies | |
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Distribution
editAgeroolithusfossils are found in the earlyMaastrichtianTremp BasinofLleida,Spain,from theUpper CretaceousofFrance,and from theLower CretaceousofGalve, Spain.[1]
History
editAgeroolithuswas first discovered and described in1997by the FrenchpaleontologistMonique Vianey-Liaudand the Spanish paleontologistNieves López Martínezwhile excavating the Tremp Basin in Spain.[1]Further specimens were discovered in Galve in1998and in France in2000.[2]In2012,Albert Sellés describedAgeroolithus-like eggshells from the Tremp Basin in his PhD thesis at theUniversitat de Barcelona.[2]
Description
editAgeroolithus fontllongensiswas first described on the basis of nine eggshell fragments.[1]Some more recently described eggshell fragments have been referred toA.aff.fontllongensis[3]andcf.Ageroolithus.[2]The eggshell has a smooth surface, and at 25–36 mm thick is thinner than most other eggs of the ratite morphotype.[1][2]Erosion andrecrystallizationheavily affect mostAgeroolithusspecimens, but a few fragments are well enough preserved to observe the microstructure. It has two structural layers with a sharp dividing line between them.[1]The inner layer, known as the mammillary layer, is composed of wedges and shows distinct growth lines, whereas the outer layer (the prismatic layer[4]) is not clearly divided into units.[1]It has narrow, straight pore canals measuring 15 to 25 μm in diameter.[2][1]
The specimens referred to cf.Ageroolithusby Sellés in 2012 are very similar toAgeroolithusin thickness, ornamentation, and the ratio between prismatic and mammillary layers. They differ fromAgeroolithusbecause their shell is composed of three structural layers instead of two.[2]
Parataxonomy
editAgeroolithushas not been placed in any knownoofamily,but it is classified in the ratite morphotype,[2]alongsideElongatoolithidae,Laevisoolithidae,Medioolithidae,andOrnitholithidae.[5]It contains asingle oospecies:A. fontllongensis.[2]
See also
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References
edit- ^abcdefghVianey-Liaud, Monique; Lopez-Martinez, Nieves (1997)."Late Cretaceous Dinosaur Eggshells from the Tremp Basin, Southern Pyrenees, Lleida, Spain"(PDF).Journal of Paleontology.71(6): 1157–1171.doi:10.1017/s002233600003609x.S2CID131405598.
- ^abcdefghSelles, Albert G. (2012).Oological Record of Dinosaurs in South-Central Pyrenees (SW Europe): Parataxonomy, diversity and biostratigraphical implications(Ph.D.). Universitat de Barcelona.
- ^Ruiz-Omeñaca, J. I., Canudo, J. I., Aurell, M., Bádenas, B., Barco, J. L., Cuenca-Bescós, G., & Ipas, J. (2004). Estado de las investigaciones sobre los vertebrados del Jurásico Superior y Cretácico Inferior de Galve (Teruel). Estudios Geológicos, 60(3-6), 179-202.
- ^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.
- ^Konstantin E. Mikhailov, Emily S. Bray & Karl E. Hirsch (1996). "Parataxonomy of fossil egg remains (Veterovata): basic principles and applications".Journal of Vertebrate Paleontology.16(4): 763–769.doi:10.1080/02724634.1996.10011364.JSTOR4523773.