Kudos to Scott Elyard to pointing this one out to me. As he notes on his website, the implications for paleo-artists like him and I are fairly obvious.
Now, a few questions immediately come to mind.
1) Why does the third finger never fossilize?
2) Does this mean that other tyrannosaurs, like Albertosaurus and Daspletosaurus have three fingers, too?
3) What was the construction of this third finger like? Would it have been useful?
4) Would the third finger have been visible outsid the skin? Did it have a claw?
Oh, my head is swimming with conjectures now.
Also, congratulations to Brian Switek of Laelaps fame, on his move to that most esteemed of science blogging sites, ScienceBlogs. I have updated the blogroll, so upon clicking "Laelaps" on the right, you will be taken to his new site. On his recommendation, I shall continue posting well-written pieces on paleo and continue submitting my blog to ScienceBlogs in hopes of someday joining him!