View source for Biology:Ageroolithus

{{Short description|Dinosaur egg}}
{{Oobox
|fossil_range = {{fossil range|145|65|[[Earth:Cretaceous|Cretaceous]]}}
|taxon = Ageroolithus
|authority = Vianey-Liaud and López-Martínez, 1997
|subdivision_ranks = Oospecies
|subdivision =
* ''A. fontllongensis'' <small>Vianey-Liaud and Lopez-Martinez, 1997</small>
}}

'''''Ageroolithus''''' is an oogenus of [[Biology:Dinosaur egg|dinosaur egg]]. It may have been laid by a theropod.<ref name=VLLM>{{cite journal |last1=Vianey-Liaud |first1=Monique |last2=Lopez-Martinez |first2=Nieves |date=1997 |title=Late Cretaceous Dinosaur Eggshells from the Tremp Basin, Southern Pyrenees, Lleida, Spain |journal=Journal of Paleontology |volume=71 |issue=6 |pages=1157–1171 |doi=10.1017/s002233600003609x|s2cid=131405598 |url=https://eprints.ucm.es/id/eprint/69803/1/3Vianey%26LopezM97-1.pdf }}</ref>

==Distribution==
''Ageroolithus'' fossils are found in the early [[Earth:Maastrichtian|Maastrichtian]] Tremp Basin of Lleida, {{wipe|Spain}}, from the [[Earth:Upper Cretaceous|Upper Cretaceous]] of {{wipe|France}}, and from the [[Earth:Lower Cretaceous|Lower Cretaceous]] of Galve, Spain.<ref name=VLLM/>

==History==
''Ageroolithus'' was first discovered and described in 1997 by the French paleontologist Monique Vianey-Liaud and the Spanish paleontologist Nieves López Martínez while excavating the Tremp Basin in Spain.<ref name=VLLM/> Further specimens were discovered in Galve in 1998 and in France in 2000.<ref name="PhD"/> In 2012, Albert Sellés described ''Ageroolithus''-like eggshells from the Tremp Basin in his PhD thesis at the Universitat de Barcelona.<ref name="PhD"/>

==Description==
''Ageroolithus fontllongensis'' was first described on the basis of nine eggshell fragments.<ref name=VLLM/> Some more recently described eggshell fragments have been referred to ''A.'' aff. ''fontllongensis''<ref name=OCABBCBI>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.</ref> and cf. ''Ageroolithus''.<ref name="PhD">{{cite thesis |type=Ph.D. |last=Selles |first=Albert G. |date=2012 |title=Oological Record of Dinosaurs in South-Central Pyrenees (SW Europe): Parataxonomy, diversity and biostratigraphical implications |publisher=Universitat de Barcelona}}</ref> The eggshell has a smooth surface, and at 25–36&nbsp;mm thick is thinner than most other eggs of the ratite morphotype.<ref name=VLLM/><ref name="PhD"/> Erosion and [[Earth:Recrystallization (geology)|recrystallization]] heavily affect most ''Ageroolithus'' specimens, but a few fragments are well enough preserved to observe the microstructure. It has two structural layers with a sharp dividing line between them.<ref name=VLLM/> The inner layer, known as the mammillary layer, is composed of wedges and shows distinct growth lines, whereas the outer layer (the prismatic layer<ref name="Paleofile">Laura E. Wilson, Karen Chin, Frankie D. Jackson, and Emily S. Bray. (2012). "[http://www.ucmp.berkeley.edu/science/eggshell/index.php Fossil eggshell: Fragments from the past]" UCMP's online fossil egg exhibit.</ref>) is not clearly divided into units.<ref name=VLLM/> It has narrow, straight pore canals measuring 15 to 25&nbsp;µm in diameter.<ref name="PhD"/><ref name=VLLM/>

The specimens referred to cf. ''Ageroolithus'' by Sellés in 2012 are very similar to ''Ageroolithus'' in thickness, ornamentation, and the ratio between prismatic and mammillary layers. They differ from ''Ageroolithus'' because their shell is composed of three structural layers instead of two.<ref name="PhD"/>

==Parataxonomy==
''Ageroolithus'' has not been placed in any known oofamily, but it is classified in the ratite morphotype,<ref name="PhD"/> alongside Elongatoolithidae, Laevisoolithidae, Medioolithidae, and Ornitholithidae.<ref name="Mikhailov">{{cite journal |author=Konstantin E. Mikhailov, Emily S. Bray & Karl E. Hirsch |year=1996 |title=Parataxonomy of fossil egg remains (Veterovata): basic principles and applications |journal=Journal of Vertebrate Paleontology |volume=16 |issue=4 |pages=763–769 |doi=10.1080/02724634.1996.10011364 |jstor=4523773}}</ref>  It contains a single oospecies: ''A. fontllongensis''.<ref name="PhD"/>

==See also==
* List of dinosaur oogenera

==References==
{{Reflist|30em}}
{{Taxonbar|from=Q4692137}}

[[Category:Dinosaur reproduction]]

{{Sourceattribution|Ageroolithus}}