Polystira oxytropis, but in the character of the sculpture they closely approach each other. Distribution. This marine species occurs in the Mexican part of the North Pacific Ocean. Polystira nobilis Polystira nobilis is a species of sea snail, a marine gastropod mollusk in the family Turridae, the turrids. Description. The fusiform shell is solid and wrinkled. The uppermost whorls are concave, slightly striated and largest near the middle of the keel. Below, it shows small alternating keels. The suture is simple. The outer lip wraps slightly inwards.It is chiefly distinguishable from it in the absence of any keel between the principal 	Polystira nobilis
11924690	Polystira oxytropis Polystira oxytropis Polystira oxytropis is a species of sea snail, a marine gastropod mollusk in the family Turridae, the turrids. Description. The horn-colored shell contains several sharp keels and numerous spiral raised lines. The upper keel is the strongest, angulating the whorls, the surface concave above it. P. oxytropis" is considered an "umbrella species" with considerable diversity as shown by DNA sequence data coupled with conchological studies. Distribution. This is an Eastern Pacific species, occurring off Western Mexico, in the Gulf of Panama and the Pacific coast of Colombia. Polystira oxytropis Polystira oxytropis is a species of sea snail