Wasn't it already 7th edition rules? Or was it more of a mix and I just assumed the rest of it fell into line?
Apparently they're called Dustback Helamites. '-Mite' as in 'dust mite', presumably.
The very last thing I was expecting - Ash Nomads were traditionally more Mad Max on motorcycles and with dune buggies, these look more like something out of Jim Henson's The Dark Crystal - but honestly, I think they're pretty cool.
I like the divergence - now that the Hive Gangs have Am-Bot and other automated minions, it feels suitable that the Ash Nomads have gone full on 'Tuskan Raiders' and use living mounts to set them apart. Neat.