I was cruising the monographs the other night, looking for new ideas, when the humerus of Opisthocoelicaudia stopped me dead in my tracks. I think you’ll agree it is an arresting sight:

Opisthocoelicaudia right humerus in lateral, anterior, medial, and posterior views, from Borsuk-Bialynicka (1977: figure 7)

Opisthocoelicaudia right humerus in medial, anterior, lateral, and posterior views, from Borsuk-Bialynicka (1977: figure 7)

I’d seen it before, but somehow I had never grokked its grotesque fatness. I mean, damn, Opisthocoelicaudia, you really let yourself go. Especially compared to the slenderness and grace of this juvenile Alamosaurus humerus:

Alamosaurus left humerus in anterior and posterior views, from Lehman and Coulson (2002: figure 7).

Alamosaurus left humerus in anterior and posterior views, from Lehman and Coulson (2002: figure 7).

Now, I realize that part of the slenderness of this Alamosaurus humerus might be because it’s a juvenile–other alamosaur humeri are a bit more robust–but it’s still a striking contrast. I couldn’t help but superimpose them, scaled to the same midshaft width:

Alamosaurus and Opisthocoelicaudia humeri superimposed

I flipped the Alamosaurus humerus left-to-right to match that astonishing lump of Opisthocoelicaudia. The result reminds me of one of Abrell and Thompson’s Actual Facts:

If you put Woodrow Wilson inside William Howard Taft, he would have stuck out by a good 18 inches.

None of that probably signifies anything more than that I am easily amused. And also,  Opisthocoelicaudia is Just Plain Wrong. You hear me, Opisthocoelicaudia? Don’t make me make you cry mayonnaise!

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