[Sorry about the late posting today: I had to leave the house at 7:15 to fly to Copenhagen for Christmas lunch — long story — and I am completing today’s post from my hotel room.] There’s no getting away from it: everyone wants to know how big dinosaurs are. Xenoposeidon is based on a single partial vertebra, so there is no way to be at all sure about the size and shape of the whole animal;

I see now that Mike has beaten me to the punch in providing your at-least-weekly dose of sauroponderous vertebrawesome. And a nice job it is. Still, I feel funny about you not getting a new picture (ahem), so I’m posting my late entry anyway. For some reason, despite–or perhaps because of–my ardent devotion to cervicals, I have taken it on myself to push the anatomical boundaries of SV-POW! again.

We promised non-presacrals and non-brachiosaurids, so here’s a diplodocid caudal vertebra in right lateral view. Most of the neural spine is blown off. The huge hole in the side of the vert is legit, though. That’s a pneumatic foramen (literally, air hole), through which air-filled tubes connected to the respiratory system entered the bone–just like in birds. More on that later.