STL Science Center

STL Science Center

26 March 2011

Edmontosaurus: The Visual Evidence.

Last Saturday I posted skulls of Anatotitan, at the top here, and Edmontosaurus for visual comparison. Here is that picture again:
As I noted before, the Anatotitan skull is thinner at the base of the skull and the bill is curved more downward. Could this be a younger Edmontosaurus trait? It has been suggested that Anatotitan is a synonym for Edmontosaurus, so this could be a reality. However, Edmontosaurus is an older species by approximately 5 million years though cohabited with Anatotitan for about the last 2.5 million years with Anatotitan outlasting Edmontosaurs for the last 0.5 million years of dinosaur rule. The timeline does not suggest that synonyms could be too far fetched at all, though my gut feeling is that Anatotitan and Edmontosaurus were at most synonymous at the genus level yet different species still; like coyotes and wolves. I get this feeling because of where they have been found. Edmontosaurus is a Canadian and American dinosaur having been found from Alberta, Canada to South Dakota as well as specimens unmentioned in literature I have found, and therefore suspect, findings of sacral and caudal vertebrae, metatarsal, and femoral bone chips found in Tennessee; again, supposedly. Anatotitan, however, are found only in South Dakota and Montana in Hell Creek formations in both and Lancian formations in South Dakota. Here are a few pictures of the suspect fossils in their display in Memphis, Tn.:

One thing we would have to look at closely would be the two skeletal structures of Edmontosaurus and Anatotitan. These I will leave off with today and let the reader make their own judgments of the skeletal structures of these two animals.
Anatotitan copei
Edmontosaurus annectens

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