Cassidae Common Name Helmet Snails
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. The family Cassidae consists of About 60 species.
Species of the Cassidae family are fiund in tropical and temperate seas from the intertidal zone to depths of 330 feet, buried in the sand during the day and becoming active at night.
(REF: Gofas, S. (2010). Cassidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species)
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 (A spire is a part of the coiled shell of molluscs. The spire consists of all of the whorls except for the body whorl. Each spire whorl represents a rotation of 360°. A spire is part of the shell of a snail, a gastropod mollusk, a gastropod shell, and also the whorls of the shell in ammonites, which are fossil shelled cephalopods. The spire, when it is not damaged or eroded, includes the protoconch (also called the nuclear whorls or the larval shell), and most of the subsequent teleoconch whorls (also called the postnuclear whorls), which gradually increase in area as they are formed. Thus the spire in most gastropods is pointed, the tip being known as the "apex". The word "spire" is used, in an analogy to a church spire or rock spire, a high, thin, pinnacle). 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.
(REF: Cook, L. M.; Jaffar, W. N. (1984). "Spire index and preferred surface orientation in some land snails". Biological Journal of the Linnean Society. 21)
Many Cassidae 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.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.
These Helmet 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.
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
echinoderm is any member of the phylum Echinodermata. The adults are recognised by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian
(REF: "echinoderm". Dictionary.com Unabridged) (REF: Hall, Danielle (3 February 2022). "Echinoderms | Smithsonian Ocean")
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Caenogastropoda
Order: Littorinimorpha
Super family: Tonnoidea
Family: Cassidae
Latreille, 1825
King Helmet Shell
Cassis tuberosa, the king helmet, is a large sea snail species with a solid, heavy shell, a marine gastropod mollusc in the family Cassidae.
(REF: Cassis tuberosa (Linnaeus, 1758))
The King Helmet species are found in the Western Atlantic Ocean in waters off North Carolina, Florida, Mexico, Honduras, Colombia, Costa Rica, Panama, Venezuela, Bermuda, Bahamas, Turks & Caicos, Cuba, Hispaniola, Puerto Rico, Virgin Islands, Leeward Islands, Windward Islands, Brazil, and in the Eastern Atlantic Ocean at the Cape Verde Islands.
These shells have been measured to in length up to 12 inches. The Cassis tuberosa is generally cream colored with dark brown spots. The dorsal surface has fine growth lines and minute spiral lines.
They have been found in minimum depths of 3 feet to maximum recorded depths of 89 feet. The King Helmets live in shallow coastal waters around sandy beaches & and in reef environments. They dwell in tandem with seagrass beds, macroalgae banks, rhodolith beds and coral rubble.
(REF: Cassis tuberosa (Linnaeus, 1758)) (REF: Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence")
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Caenogastropoda
Order: Littorinimorpha
Family: Cassidae
Genus: Cassis
Species: C. tuberosa
Binomial name: Cassis tuberosa
(Linnaeus, 1758)
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C3-4
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C4-4
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C5-4
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