GP Tactics: Unusual Mating Motif

I was surprised to find two examples of the same unusual mating pattern in the tactics subset I created before Christmas.  In the first position, I was losing anyways, but allowed an immediate resolution:

 
1.Kg3?? Rg1# , a type of epaulette mate.

The second example required a finesse move:

 
The immediate 1.Rb6?, as played by me, allows the king to escape with 1…Kc5.  However, 1.Rd5! threatens 2.Rb5#.    Black can only avoid mate by giving up a lot of material, e.g. 1…Rxc4.
A king in front of two isolated enemy pawns has its liberties seriously curtailed.