Arriagadoolithidae is an
oofamily
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of t ...
of
fossil egg
Egg fossils are the fossilized remains of eggs laid by ancient animals. As evidence of the physiological processes of an animal, egg fossils are considered a type of trace fossil. Under rare circumstances a fossil egg may preserve the remains of ...
s, representing the eggs of
Alvarezsaurs
Alvarezsauroidea (from the Argentine historian, writer and physician Gregorio Álvarez) is a group of small maniraptoran dinosaurs. The group was first formally proposed by Choiniere and colleagues in 2010, to contain the family Alvarezsauridae ...
.
Description
The eggs are well stratified with three layers: the external, the prismatic, and the mammillary. The connection between prismatic and external layers is abrupt. The eggshell is similar to that of
bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s, and has ornamentation similar to that of
Elongatoolithids.
History
Previously, Arriagadoolithid eggs were considered to be
Elongatoolithids, because the similarities in shell ornamentation. However, they have quite distinct eggshell structure, which was recognized by Jackson and Varricchio (2010) when they named a new oogenus, ''
Triprismatoolithus''. The oofamily was first described in 2012, following the discovery of fossil eggs associated with the Alvarezsaur, ''
Bonapartenykus
''Bonapartenykus'' (meaning "José Bonaparte, José F. Bonaparte's claw") is a monospecific genus of alvarezsauroidea, alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the uppe ...
''; Agnolin ''et al'' erected a new oogenus, ''
Arriagadoolithus
''Arriagadoolithus'' is the oogenus of fossil eggs which includes the eggs of the alvarezsaurid ''Bonapartenykus''. Fossils of the creature were found in Patagonia; it may have brooded on its eggs.
Description
''Arriagadoolithus patagoniensis'' i ...
'', and oofamily, Arriagadoolithidae, to contain ''Arriagadoolithus'' and ''Triprismatoolithus''.
Palaeobiology
''Arriagadoolithus'' eggs are known to belong to ''Bonapartenykus'', because the fossils were found in close association. ''Triprismatoolithus'' has not been found in association with any skeletal remains; however, the close resemblance between ''Triprismatoolithus'' and ''Arriagadoolithus'' implies that ''Triprismatoolithus'' may be the eggs of an as-of-yet unknown Alvarezsaurid.
References
Arriagadoolithidae
{{eggshell-stub