Aerosteon

Aerosteon is a genus of megaraptoran dinosaur from the Late Cretaceous period of Argentina. Its remains were discovered in 1996 in the Anacleto Formation, which is from the late Campanian. The type and only known species is A. riocoloradensis. Its generic name can be translated as "air bone" and derives from Greek ἀήρ (aer, "air") and ὀστέον (osteon, "bone"), whereas its specific name indicates that its remains were found 1 km (0.6 miles) north of the Río Colorado, in Mendoza Province, Argentina. The genus shows evidence of a bird-like respiratory system.

==Discovery== thumb|left|Neck vertebrae Aerosteon was first discovered in 1996 and was first described by Sereno et al. in a paper which appeared in the online journal PLoS ONE in September 2008. However, at the time, the International Code of Zoological Nomenclature did not recognize online publication of names for new species as valid unless print copies were also produced and distributed to several libraries, and that this action is noted in the paper itself. PLoS ONE initially failed to meet this requirement for Aerosteon. On May 21, 2009, the journal's managing editor coordinated with the ICZN to correct this oversight, publishing a comment to the original paper with an addendum stating that the requirements had been met as of that date. Consequently, though the description appeared in 2008, Aerosteon was not a valid name until 2009.