The biology of the Northeastern Pacific Turridae. V. Demersal development,synchronous settlement and other aspects of the larval biology of Oenopota levidensis

Summary

The larval development and metamorphosis of a turrid gastropod is described for the first time. This snail, Oenopota levidensis, is typical of the boreal genus Oenopota, which has over 150 described species. Development to a veliger occurs within a lenticular capsule in about 50 days. The capsules hatch to release veligers which swim for less than a week. The remainder of their planktotrophic larval period is spent demersally. Demersal veligers assumed one of two characteristic postures; they remain on the bottom with the velum either extended laterally or folded over the shell. These demersal veligers continue development and metamorphose after another 25 days. The majority of the veligers in the 55 cultures examined metamorphosed and settled within a 96-h period, even though their oviposition occurred over a 47-day period. Potential selective forces leading to this synchronous settlement are proposed.