Bayerotrochus midas Bayer (F.M. Bayer, 1966)
Slit shells are named for the narrow, open slit in the last part of the body whorl, on each side of which is an internal gill. Bayerotrochus midas, King Midas's Slit Shell, is the deepest dwelling pleurotomariid snail in the western Atlantic. This species inhabits steep rocky walls at depths ranging from 1,400 to 2,800 ft, and ranges from southern Georgia (USA) throughout the Bahamas and into the Caribbean. The southern limits of this species are still poorly known, and the known range will likely expand considerably with additional deep water sampling throughout the Caribbean and along the northern coast of South America. Where pleurotomariids have been thoroughly studied using research submarines, three species were found to occur along steep-walled coasts. However, each of the three species has a narrow range depth range that does not overlap with the other two species.
Like all pleurotomariids, Bayerotrochus midas feeds primarily on sponges, but has occasionally been observed eating soft corals and stalked crinoids. Despite their thin, fragile shells, pleurotomariids are able to suvive attacks by predators by producing an opaque, viscous secretion when disturbed. Large quantities of this secretion are produced rapidly by the paired hypobranchial glands that occur on each side of the slit.
The outer calcitic layer of the shell is so thin as to be translucent; light passing through it is reflected off the inner, nacreous layer producing a shiny golden color that inspired the specific epithet “midas.” The genus Bayerotrochus was named to honor the late Dr. F. M. Bayer, who discovered and described this species, in recognition of his many contributions to the study of western Atlantic invertebrates, especially corals and mollusks.