Originally Posted by Leukybear

Yep. That's a time-trial chainring. It's not cheap either at ~$100.
Let's see road/ time trial rear axle spacing has been 130mm standard since road groups have been 9 speed; we're up to 11 speed now.
How are these additional speeds fit into the same axle space?

With thinner cassette cogs and corresponding 9/10/11 speed specific chains which vary in width in order to maneuver in between those ever thinner cogs. As a result, chainrings which also interact directly with this chain has to be thinner too abit a little less noticeable than casettes considering there's only 2 up front.
Flip side for manufacturers is that this also lessens the weight of their groupset which is a "serious" selling point for weightweenie roadies.