Cassidae

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Cassidae
Semicassis pyrum (top).JPG
Lateral view of a shell of Semicassis pyrum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Caenogastropoda
Order: Littorinimorpha
Superfamily: Tonnoidea
Family: Cassidae
Latreille, 1825
Genera

See text

Synonyms [1]
  • Cassididae Gyllenhal, 1813
  • Oocorythidae P. Fischer, 1885

The Cassidae are a taxonomic family of medium-sized, large, and sometimes very large sea snails commonly called helmet snails or bonnet snails. These are marine gastropod mollusks in the superfamily Tonnoidea and the clade Littorinimorpha. [1]

Contents

About 60 species comprise the family Cassidae; an example is Cypraecassis rufa .

Nomenclature

Despite its incorrect formation (the correct one would be Cassididae, based on the genitive form of Cassis), the ICZN has placed the name Cassidae Latreille, 1825 on the official list of family names, therefore avoiding homonymy with Cassididae Stephens, 1831 (based on Cassida Linnaeus, 1758, a chrysomelid beetle); Opinion 1023 (1974, Bulletin of Zoological Nomenclature 31: 127–129). [1]

Distribution

Species of this family occur in tropical and temperate seas from the intertidal zone to depths of 100 m (330 ft), buried in the sand during the day and becoming active at night.

Shell description

Members of this family are shaped rather like bonnets or helmets, as their common name suggests. The shells are large, thick, subglobular with dextrally coiled, sometimes varicose, whorls, and a short spire. The coiling may be trochospiral or convoluted. The shells of many species have great variability, which has led to many misidentifications, resulting in many synonyms.

Many species have a large and solid shield over the parietal body or beside the thick, plicated columella. Many species show blunt knobs and thickened axial ridges, known as varices. The thin, horny operculum is oval in shape and covers a long aperture. The siphonal canal is straight or slightly curved. The outer lip is somewhat thicker at its margin and toothed on the inside.

Anatomy

These snails have a large mantle and a large, muscular foot. Their large head has an extensible snout. The eyes are at the base of the single pair of tentacles.

Feeding habits

Helmet bonnets prey on echinoderms (especially sea urchins), starting by gripping them using the foot. The snail then makes a hole in the urchin through the combined action of a secretion which is rich in sulfuric acid and by rasping with their radula. The acid secretion is provided by two large proboscis glands. [2]

Taxonomy

In their taxonomy of the Gastropoda of 2005 Bouchet & Rocroi still listed Cassidae as Cassinae Latreille, 1825, a subfamily of Tonnidae Suter, 1913 (1825), following in this Riedel (1995). [3] In his "Revision of the deep-water Cassidae" however, Beu raised in 2008 Cassinae to the rank of family. [4]

Genera

Genera within the family include:

Genera brought into synonymy

Human uses

Some helmet shells are carved into cameos, starting in Italy in 1820.

Related Research Articles

<span class="mw-page-title-main">Scotch bonnet (sea snail)</span> Species of mollusc

The Scotch bonnet is a medium-sized to large species of sea snail, a marine gastropod mollusk in the subfamily Cassinae, the helmet shells and bonnet shells. The common name "Scotch bonnet" alludes to the general outline and color pattern of the shell, which vaguely resemble a tam o' shanter, a traditional Scottish bonnet or cap. The shell is egg-shaped and fairly large, 2 to 4 inches in maximum dimension, with a regular pattern of yellow, orange or brown squarish spots. The surface sculpture of the shell is highly variable: the surface can be smooth and polished, have grooves, be granulated, or even be nodulose on the shoulder of the whorls.

<span class="mw-page-title-main">Tonnidae</span> Family of gastropods

The Tonnidae are a family of medium-sized to very large sea snails, known as the tun shells. These are marine gastropod molluscs in the clade Littorinimorpha. The name tun refers to the snails' shell shape, which resembles wine casks known as "tuns". While thin, the shells are also strong and lack opercula. They are found in all tropical seas, where they inhabit sandy areas. During the day, they bury themselves in the substrate, emerging at night to feed on echinoderms, crustaceans, and bivalves. Some larger species also capture fish, using their expandable probosces to swallow them whole. Females lay rows of eggs that become free-swimming larvae for several months before settling to the bottom.

<i>Casmaria perryi</i> Species of gastropod

Casmaria perryi is a species of predatory sea snails, marine gastropod molluscs in the subfamily Cassinae, the helmet snails and bonnet snails.

<span class="mw-page-title-main">Tonnoidea</span> Superfamily of gastropods

The Tonnoidea are a superfamily of sea snails, marine gastropod molluscs in the order Littorinimorpha. This superfamily includes many very large species.

<i>Phalium areola</i> Species of gastropod

Phalium areola, common name the checkerboard bonnet, is a species of sea snail, a marine gastropod mollusc in the subfamily Cassinae, within the family Cassidae the helmet and bonnet shells. It is also known as the checkerboard bonnet shell.

<i>Semicassis</i> Genus of gastropods

Semicassis is a genus of medium-sized predatory sea snails, marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails.

<i>Cassis</i> (gastropod) Genus of gastropods

Cassis, common name the helmet shells, is a genus of very large sea snails, marine gastropod mollusks in the family Cassidae, the helmet shells and their allies. This is the type genus of the subfamily Cassinae.

<i>Casmaria ponderosa</i> Species of gastropod

Casmaria ponderosa, common name the heavy bonnet, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Echinophoria coronadoi</i> Species of gastropod

Echinophoria coronadoi is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Galeodea alcocki</i> Species of gastropod

Galeodea alcocki, common name : Alcock's false tun, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Galeodea echinophora</i> Species of gastropod

Galeodea echinophora, the spiny bonnet or helmet shell, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

Galeodea plauta is a species of large sea snail, a marine gastropod mollusc in the family Cassidae, the helmet snails and bonnet snails.

<i>Galeodea rugosa</i> Species of gastropod

Galeodea rugosa, common name : the rugose bonnet, is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Oocorys grandis</i> Species of gastropod

Oocorys grandis is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Oocorys sulcata</i> Species of gastropod

Oocorys sulcata is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Semicassis faurotis</i> Species of gastropod

Phalium faurotis is a species of large sea snail, a marine gastropod mollusk in the family Cassidae, the helmet snails and bonnet snails.

<i>Phalium</i> Genus of gastropods

Phalium, common name the bonnet shells, is a genus of large sea snails, marine gastropod molluscs in the subfamily Phaliinae of the family Cassidae, the helmet shells, bonnet shells and their allies.

<i>Galeodea</i> Genus of gastropods

Galeodea is a genus of large sea snails, marine gastropod mollusks in the subfamily Cassinae of the family Cassidae.

<i>Casmaria</i> Genus of gastropods

Casmaria, is a genus of medium-sized sea snails, marine gastropod molluscs in the subfamily Phaliinae of the family Cassidae, the helmet shells and their allies.

<i>Echinophoria</i> Genus of gastropods

Echinophoria is a genus of large sea snails, marine gastropod mollusks in the family Cassidae, the helmet snails and bonnet snails.

References

  1. 1 2 3 Gofas, S. (2010). Cassidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=22999 on 2011-01-19
  2. ↑ Hughes, RN | Hughes, HPI, Morphological and Behavioural Aspects of Feeding in the Cassidae (Tonnacea, Mesogastropoda) ; Malacologia. Vol. 20, no. 2, pp. 385-402. 1981. Archived August 29, 2012, at the Wayback Machine
  3. ↑ Riedel F. 1995. An outline of Cassoidean phylogeny (Mollusca, Gastropoda). Contributions to Tertiary and Quaternary Geology 32(4): 97–132
  4. ↑ Beu A.G. (2008) Recent deep-water Cassidae of the world. A revision of Galeodea, Oocorys, Sconsia, Echinophoria and related taxa, with new genera and species (Mollusca, Gastropoda). In Héros V., Cowie R.H. & Bouchet P. (eds), Tropical Deep-Sea Benthos 25. Mémoires du Muséum National d'Histoire Naturelle 196: 269-387.
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