I have a worldbuilding project going at the moment.
It surrounds a few sapients two of which are bird-like animals from a taxon I'm fleshing out> A much more earth-like bunch of animals known as Cyannosiums. The land is to be dominated at least twice by animalia. The Cyannosiums are much newer than the other phylum.

The bunch I'm gonna describe now are in their infantile stages and I'm open to ideas on how to develop them.
As of now, I'm going to call them Arthrochelyfos(jointed shells) as their internalities are some shells linked by a notochord and joints. Still working out the kinks in thier physical appearance but the current concesus on thier defining characteristics are as follows.

1. 3 eyes set above the jawline
2. 4 limbs for moving along
3. complex mouthparts used to manipulate the world like hands in sapients
4. forked "tails"
5. cranial or cervical genitalia
6. primitive lungs similar to a lungfish that must be hydrated on a weekly basis- openings to which are located on back
7. wierd tongue-like appendages to track smells in the air
8. green- yellow blood

Any ideas of thoughts are appreciated, Im trying to make them pretty alien but still reasonable.

developmental sketches