Chris Matthews dropped the ball on his piece about Republicans and their anti-science stance on Thursday May 6 2009. He thought he'd be able to prove a point using Tom Tancredo. He came close by bringing up the Scientific Method but he so badly botched the evolution discussion because he let Tancredo say "there's no evidence of transitional species" unchecked. Wikipedia has a list of transitional fossils. At that point he was left with no time to get into climate change denial being spurred by anti-science and anti-evidence.
Probably the most noteworthy of these because of its relatively recent discovery (unearthed in 2004) is the Tiktaalik. Here's an important snippet, emphasis mine:
Tiktaalik represents an intermediate form between fish and amphibians. Unlike many previous, more fishlike transitional fossils, Tiktaalik's 'fins' have basic wrist bones and simple fingers, showing that they were weight bearing. Close examination of the joints show that although they probably were not used to walk, they were more than likely used to prop up the creature’s body, push up fashion. The bones of the fore fins show large muscle facets, suggesting that the fin was both muscular and had the ability to flex like a wrist joint. These wrist-like features would have helped anchor the creature to the bottom in fast moving current
Here's a picture of it:
I kind of like this artist rendition because its head looks kinda cartoony. That to me makes the Tiktaalik a pretty good candidate to be the poster transitional specie. If not the Tiktaalik then maybe some other transitional specie, maybe we should try a few different ones on t-shirts and bumper stickers and figure out which one has the simplest shape while still having its different features easily discernible. In any case I'll never forget the name Tiktaalik whenever I hear anyone with the false argument of there being no transitional species. I may forget how to spell it correctly but as far as I'm concerned that's my new mascot.