The cover of the Warhammer 40K: Deathwatch RPG's core rulebook depicts several space marines. One of them (second from the left in the picture below) is wearing an unusual snouted helmet design.
At first I thought it might be a Mk. IV-pattern helmet, but that doesn't seem right as the vents are not aligned the same way.
It also seems to have "ears" moulded into it. Given this, as well as the pelt on the marine's shoulders, it seems like the marine may be a Space Wolf. Could this be some sort of artificer-made armour mark?
Thanks in advance for any suggestions as to what this armour/helmet design may be.