Hadrosaurus Reevaluated, Twice

©Sergey Krasovskiy

I asked if I could use this image earlier in the week without the background. He sent it to me like this with a background. I thought it would be nice to head up this column today. What I really aimed to present today were papers that have come out recently (within the 6 years) that discuss reevaluation of Hadrosaurus. It seems like just about any mention of a reevaluation these days also has Jack Horner as a footnote if not a second, or in this case third, author. Albert Prieto-Marquez and David Weishampel, along with Horner, reevaluated the position and description of Hadrosaurus in 2006. Their determination, to sum up a longer article very briefly, was that the type specimen of Hadrosaurus has no characters which distinguish it from any other animal and that the name is therefore defunct. They made special mention of the idea that it is not synonymous with any other animal and that phylogenetically it belongs in the Euhadrosauria to an undetermined species.

The second paper I found is a short correspondence (if anyone has the full length correspondence that would be nice to find) authored by Albert Prieto-Marquez alone, dated 2011, in which he somewhat refutes his own previous paper and reevaluates Hadrosaurus yet again. He argues that Hadrosaurus actually is diagnosable "based on a combination of plesiomorphic and derived appendicular characters." I am interested to read the full length of this paper. I still have some of the first paper to read ahead of that anyhow though.