Cold-Water Conidae:  Toxoglossate Turrid Snails of The Northeastern Pacific

Oenopota levidensis, one of the most common of the venomous conid or turrid snails from the Pacific Northwest of North America. The animal is about 1.5 cm long (3/5 inches).

The conid snails constitute a very large fraction of Prosobranchs, and most of this diversity is found in the cold water species placed in what taxonomists used to call the Family Turridae. These animals are now placed into several subfamilies in the revised Family Conidae. This taxonomic position reflects their possession of a venom apparatus and, in some of them, hypodermic harpoon-like teeth similar in most details to those found in the mostly tropical genus, Conus.  Practically and functionally, the venom apparatus and teeth in many turrids differ from those found in cone snails only in size.  The photographs on this page illustrate one of the many conids found in the shallow-water Northeastern Pacific, Oenopota levidensis. Oenopota is a huge genus with well over 150 species, and owes its success to specialization both on prey and on habitat. Oenopota levidensis preys on spionid and oweniid worms, in the Puget Sound region of Washington, U. S. A.  Its diet elsewhere is unknown, although the snail is reasonably widespread. The animals are found in both sandy and rocky substrates, probably due to the presence of their prey in these areas. Oenopota levidensis may reach densities of over 20 animals per square meter in parts of the San Juan Islands of North Puget Sound.

Oenopota levidensis, and its harpoon-like, hypodermic, tooth. The snails jab the tooth into worm, inject venom and then eat the dead worm. The scale bar to the left is 1 cm for the worm. The bar to the right is 0.1 mm for the tooth.

Spawning occurs in the winter. Females living in sandy areas seek out large bivalve shells or rocks for oviposition. Females in rocky areas deposit their egg capsules on rocks, mostly on vertical surfaces. The embryos develop through a trochophore and early veliger stage in the egg capsules and all of the eggs in a capsule develop. The eggs hatch to release swimming veligers, and the duration of this development is temperature dependent. Although capable of swimming, the veligers are demersal through most of their development and remain on the bottom unless disturbed. They may spend as long as 100 days as feeding larvae. Settlement appears to occur shortly after settlement of Polydora sociali, one of their preferred prey and may be synchronous throughout the population with all veligers metamorphosing within a few days, regardless of their time as a veliger. Completion of metamorphosis is rapid and the young juveniles are crawling and searching for food within two days.

Left: Oenopota levidensis ovipositing on the wall of a glass jar. The edges of the egg capsule are indicated by the arrows. All of the eggs will develop as veligers and leave the egg capsule for planktotrophic development. Right: 10 day post-hatching Oenopota levidensis veliger; about 0.8 mm across the velum.



Relevant References:

Shimek, R. L. 1983. Biology of the Northeastern Pacific Turridae. I. Ophiodermella. Malacologia. 23: 281 - 312.

Shimek, R. L. 1983. Biology of the Northeastern Pacific Turridae. II. Oenopota. The Journal of Molluscan Studies. 49: 149 - 163.

Shimek, R. L. 1983. The biology of the Northeastern Pacific Turridae. III. The habitat and diet of Kurtziella plumbea (Hinds, 1843). The Veliger. 26: 10 - 17.

Shimek, R. L. 1984. The biology of the Northeastern Pacific Turridae. IV. Shell morphology and sexual dimorphism in Aforia circinata (Dall, 1873). The Veliger. 26: 258 - 263.

Shimek, R. L. 1986. The biology of the Northeastern Pacific Turridae. V. Demersal Development, synchronous settlement and other aspects of the larval biology of Oenopota levidensis. International Journal of Invertebrate Reproduction and Development. 10: 313- 337.

All Photographs on this page are copyright to Ronald L. Shimek and may not be used without permission.


Ron Shimek