Pelicanautiloids

Based heavily upon Thomastapir's Pelicanautilus [link] .

For the past few weeks, I've been at an impasse in terms of drawing aliens. I wanted to avoid basing the jaws in derived gills / limbs.

And then I saw the Pelicanautilus - which, perhaps unintentionally, made me think more like the suction strategies of sturgeon and whales...the jaw exists only to support the skin and muscle needed for that.

The bottom pair are what I suspect the default strategy is for this clade.

On the middle right, is one of the ancestral forms, which not only gave rise to the Pelicanautiloids, but also to a shell-stalked family that may appear like a cross between a sea lily and a barnacle (and a pelican, naturally)

The top right is a member of a shell-less clade which arose from the same ancestor as the above-named early Pelicanautiloid. Yep, the tentacles are more fins, and the jawbone isn't split down the middle - as it is used to stir up the seafloor in the hunt for burrowing prey.

On the middle right, is an intermediate form - between the straight-shelled ancestor & the coiled Pelicanautilus.....the shell here is coiled partly, but it coils to the side slightly, so the creature can cling to rocky outcrops, and swing the jaw towards prey.

One proto-Pelicanautiloid that came to mind as I was scanning this in, was in the sawfish niche - its shell is a flat plate protecting the body; the tentacles are slightly finny, and are arrayed the length of the body*.

* = this isn't because that part is very big - the tentacles' portion is simply stretched up and over the sides themselves.