- Muricidae, the largest family among the marine snails, have extremely variable shells.
All are active predators and tropical or semi-tropical in habitat. Most have radulas adapted for tearing flesh and capable of
drilling. However, for most, chipping away the edges of a clam shell is preferred to
boring. In borers, an accessory boring organ secretes a calcium chelating compound that
softens a shell during the drilling process, like the naticids.
Drilling is then carried out by the radula. The paralytic agent that the most muricids use
for killing is a neurotoxic mucus secretion of the hypobranchial gland. Oddly enough, this
secretion also turns up in several entirely unrelated gastropod families. The mucus secretion, particularly from the Thaiidinae (see below), has been used
also by people of antiquity, to manufacture a remarkably stable purple dye (Monfils, 2001).
- Abbott & Dance identify six
distinct subfamilies of the Muricidae, largely based on detailed features of the
radula. Several were formerly considered separate families.
- Muricinae. Immediately recognizable as murex
species, the shell is generally club-shaped with a rond aperture and anterior canal.
Bizarre varices. or projecting leafs of the shell (laid down by the mantle, as it grows)
- Ocenebrinae. Shell shapes are variable, but the
aperture is elongated and the anterior canal is closed off in most adults. Urosalpinx,
is a borer that causes much damage to oyster beds (see radula). The hole it drills for inserting its
proboscis is generally rough, somewhat uneven and less beveled than the hole made, for
example, by a moon snail (naticids).
- Thaiidinae. Shells are generally compact, lack
varices, and are sometimes knobby. The Tyrian purple dye imported by the ancient Romans
was made from bulk harvests of Thais and Purpura species. Their indigo
secretion is neurotoxic to other organisms and probably used offensively. Some thaids also
get at a clam's soft tissue by wedging open the clamshell using a strong tooth developed
at the outer lip of their own shell. This is a type of feeding behavior similar to that of the Buccinidae family. See for example (Buccinum undatum opening a clam).
- Trophoninae. These murex shells are thin for their
size and typically have rather fragile, arched varices. The aperture is also markedly
elongated, with a strong anterior canal. Austrotrophon cerrosensis is
representative, but many other species are poorly characterized.
- Typhininae. Shells are like those of the Muricinae
subframily generally except that the tips of varices are tubular, and the latest varix
opens into the aperture. Tubular tips on earlier varices are plugged off.
- Rapaninae. The genus Rapana (not to be
confused with the genus Rapa, in the Coralliophilinae subfamily), is rather similar to
Drupa in the Thaiidinae subfamily, but it lacks a tooth at the bottom of the shell
lip for prying open clams. It has a canal at the rear of the aperture and is also a
very sturdy shell.
- The Muricidae family also includes the Coralliophilinae and Columbariinae subfamilies, most of which show similar developmental features for carnivorous feeding.
- Class: Gastropoda
- Clade: Neogastropoda
- Superfamily: Muricoidea
- Family: Muricidae
- Major Subfamilies & Genera
- Subfamily: Muricinae
- Genus: Bolinus
- Genus: Chicoreus
- Genus: Haustellum
- Genus: Hexaplex
- Genus: Homalocantha
- Genus: Marchia
- Genus: Maxwellia
- Genus: Murex
- Genus: Muricanthus
- Genus: Phylonotus
- Genus: Pterynotus
- Genus: Purpurellus
- Genus: Siratus
- Subfamily: Ocenebrinae
- Genus: Ceratostoma
- Genus: Favartia
- Genus: Muricopsis
- Genus: Ocenebra
- Genus: Pteropurura
- Genus: Urosalpinx
- Genus: Vitularia
- SubFamily: Rapaninae
- Genus: Chorus
- Genus: Forerria
- Genus: Rapana
- SubFamily: Thaidinae
- Genus: Drupa
- Genus: Nucella
- Genus: Purpura
- Genus: Thais
- Subfamily: Trophoninae
- Genus: Acanthotrophon
- Genus: Austrotrophon
- Genus: Trophon
- Genus: Trophonopsis
- Subfamily: Typhininae
- Genus: Typhinellus
- Genus: Typhis
Chicoreus virgineus (Roding, 1798)
(a rare shell)
Hexaplex fulvescens (Sowerby, 1834)
Giant Eastern Murex
Purpura persica (Linn,, 1758)
SEE A LIVE OYSTER
DRILL IN ACTION:
Cohen, Andrew N. 2005 Guide to the Exotic Species of San Francisco Bay