rhyncholite One of the beak-like structures which are considered to be the upper jaw structures of fossil cephalopods (Cephalopoda). They are approximately rhomboidal in shape, with a slightly concave lower surface. The anterior portion is termed the hood, the posterior portion the shaft. The first examples are found in the Carboniferous.

rhyncholite One of the beak-like structures which are considered to be the upper-jaw structures of fossil cephalopods (Cephalopoda). They are approximately rhomboidal in shape, with a slightly concave lower surface. The anterior portion is termed the hood, the posterior portion the shaft. The first examples are found in the Carboniferous.