The Turridae are one of the largest families of marine molluscs, comprising a great number of species. A diagnostic feature of the group is the notch or sinus in the upper part of the outer lip, clearly visible in Thatcheria, which has however been considered sufficiently unusual as to have been sometimes placed in a family of its own (Thatcheriidae).
Turrids are generally shallow water, off-shore molluscs which prey on marine worms, but Thatcheria mirabilis is found only in deep waters where it occurs on muddy bottoms at depths ranging from 60 to 400 meters (200 to 1300 feet).
In common with other carnivores in the superfamily Conoidea, the turrids possess the same venomous harpoon mechanism as the genus Conus. Together with highly modified radular teeth, it is used for paralyzing the prey before swallowing.
Thatcheria mirabilis foregut (image with acknowledgement to Professor J.D.Taylor).