Tuesday, October 4, 2011

Enantiornithes Timing

Let's look at some material about the timing of Enantiornithes.
"Enantiornithines have been found in North AmericaSouth AmericaEuropeAsia, and Australia. Known fossils attributable to this group are exclusively Cretaceous and it is believed that enantiornithines became extinct at the same time as their non-avian dinosaur relatives. One biogeographic study in the 1990s[citation needed] suggested that the distribution of enantiornithines implies a Middle Jurassic origin for the clade, but this theory has not been widely accepted by paleoornithologists; a Late Jurassic/Early Cretaceous origin is more in line with the fossil record. The earliest known enantiornithines are from the Early Cretaceous) of Spain (e.g. Noguerornis, a basal genus) and China (e.g. Protopteryx) and the latest from the Late Cretaceous of North and South America (e.g. Avisaurus)."

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