Finally, but stupidly I believe.
You should see the test sprites indicating the animation sets for melee combat.
Stupidly because I believe there was an Exarch power of leaping at that point in time which allowed the Exarch to be able to ranged melee beyond H2H range. My memory is from 20 years ago and we all know how perfect long term memory is.
I will look into this in time and see if it is a real Exarch power as Eldar hasn't been a long standing attention getter.
Either way there is the Striking Scorpion Exarch.
I knew there had to be a guide for programming and it looks like the extra sprites are just wasted space. Except the Exarchs.