Worm Shells of the Vermetidae Family

Two Worm Shells of the Vermetidae Shells of the Vermetidae Family can be found in this website:

Phylogeny: Worm Shells of the Vermetidae Family are gastropod mollusks in the order Littorinimorpha. This order is large and very diverse in shape including snail-like, cowry shaped, and limpet-like. Most are marine species but some are found in freshwater or on land. They all have a twisted shell and a muscular foot that is used for movement. The key characteristic is that they all exhibit torsion, which is a process where the body twists so that the anus, gills, mantle cavity, and reproductive organs all point forward. There are sixteen superfamilies in this large order. The Vermetidae Family is the only family in the superfamily Vermetoidea. The Vermetidae Family is moderate in size, with no subfamilies, thirteen genera, and around two hundred seven species. Shells in this family are also called Vermetids.

Description: Worm Shells are long and tubular in shape, and small to large in size. They may be regularly or irregularly coiled. They begin life as typical spiraled gastropods, but soon cement themselves to a solid surface and begin to grow in loose coils. Some exist as individuals and others cement themselves into tightly interwoven colonies. Their external sculpting usually includes length-wise ridges, but may also consist of cross-wise ridges or scales. Most are whitish in color, but brown, purple, and yellow may also be seen. The interior of the shells is smooth and slightly glossy. This glossy interior allows these shells to be distinguished from the similar shells of annelid worms which are dull and chalky. Many, but not all, Worm Shells have an operculum. Because of their curvy shape, it is difficult to accurately measure some of the species in the family. The longest species in this family reach around 47 cm ( 18.5 inches) in length.

Habitat and Distribution: Worm Shells are found attached to coral, pilings, rocks and other shells from the low intertidal zone to depths up to 1832 m (6,009 feet). They are found worldwide in tropical to temperate seas. At least thirteen species from this family are found in Mexican waters.

Natural History: Worm Shells are suspension feeders, either filtering suspended nutrients through their gills, or by extruding mucous nets into the water column to collect nutrients and then withdrawing the net to feed. In turn, they are preyed upon by crabs, fish, and mollusks.  They are gonochoric and reproduce sexually. Reproduction occurs when males broadcast spermatophores (packets of sperm) into the surrounding water. The females capture these spermatophores and move them to their mantle cavity, where the eggs are fertilized and brooded.  The eggs usually hatch out as juvenile snails and not planktonic larvae.  Some species produce nurse eggs, which are used as a food source for the developing snails.