Horned snail
| Horned snail | ||||||||||||
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Casing of Cassis cornuta |
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| Scientific name | ||||||||||||
| Cassis cornuta | ||||||||||||
| ( Linnaeus , 1758) |
The horned helmet snail or large balaclava ( Cassis cornuta ) is a snail from the family of helmet snails (genus Cassis ), which is widespread in the Indo-Pacific . It feeds mainly on sea urchins .
features
The egg-shaped, bulbous snail shell of Cassis cornuta , drawn in a reticulate or mesh-like manner and surrounded by three belts, has a whitish surface. In younger animals, two belts are flat and spotted, in older animals, on the other hand, all three are nodular, with the front, largest nodes shaped like horns. The lip is lemon yellow, the inside of the case mouth is colored orange. The right edge of the spindle is provided with a row of thick teeth, the spindle folds are not particularly extensive. In fully grown snails, the house reaches around 22 cm, sometimes up to 36 cm in length. The serrated operculum resembles a bird's claw. The animal itself is brightly yellow in color. The top of the foot has a narrow brown stripe parallel to the edge and further inside a wider brown stripe. The siphon is kept the course of the Siphonalkanals according perpendicular and does not project far out from this. The eyes sit on the widened base of the otherwise thin antennae.
distribution
The horned helmet snail is found in the Red Sea , in the Indian Ocean, among others on the coast of East Africa and around Madagascar, and in the Pacific Ocean to eastern Polynesia , north to Japan and Hawaii and south to southern Queensland and New Caledonia .
habitat
Horned helmets live in the coastal fringes and in coral reefs on sand below the intertidal zone at depths of 2 to at least 40 meters. It is often buried in the sand or mud, where it also looks for prey.
Life cycle
Like other helmet snails, Cassis cornuta is separate sexes. The male mates with the female with his penis . The female lays the eggs in clusters of numerous horny egg capsules, each containing several hundred eggs. Most of the eggs develop into embryos. The pelagic phase of the Veliger larvae from hatching from the egg capsule to metamorphosis into the finished snail takes about two months.
food
Cassis cornuta feeds on echinoderms . Preferred prey are sea urchins , including heart urchins in particular , which burrow in the sand, but also other species such as. B. Tripneustes gratilla . The snail clamps the prey with the edge of the housing and guides the proboscis between the spines to the shell. Here, with the help of saliva, which contains sulfuric acid, the lime in the shell is converted into gypsum. The snail can grate this away with its radula . The snail guides its proboscis through the hole and eats the prey from the inside.
Importance to humans
Cassis cornuta is a popular collector's item due to its snail shell, so that humans can be regarded as a main enemy. It is therefore endangered in many places, but is not included in the red list worldwide. Because of the flesh, too, man follows you. In some places the snail is traditionally roasted in the shell over the fire and then the shell is smashed. Since the prey of the horned helmet snail also includes the coral-eating crown of thorns ( Acanthaster planci ), the snail has been placed under strict protection in Queensland . On the Marshall Islands , it was possible for the first time to breed young horned helmets from two females and one male in 2004.
Individual evidence
- ↑ a b c C. Brüggemann (1838): The natural history in faithful illustrations and with a detailed description of the same. Eduard Eisenach publisher, Leipzig 1838. Die Weichthiere, p. 69. The horned balaclava. (Buccinum (Cassis) cornutum L. s. Labiatum Chemn.)
- ↑ Sealifebase: Cassis cornuta Linnaeus, 1758, horned helmet ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Manoj R. Nair: CMI Land Grant Aquaculture Research Program achieves breakthrough in producing baby horned helmet shells (Cassis cornuta) , SPC Trochus Information Bulletin # 11 (September 2004), p. 11.
literature
- Marc Hughes: Hawaiian Gastropod Echinovores: The Hunting and Feeding Techniques of Cassis cornuta, Charonia tritonis, and Tonna perdix (PDF; 1.3 MB) ( Memento from October 22, 2012 in the Internet Archive ). Hohonu - A Journal of Academic Writing, Volume 1, Number 1, Hilo / Hawaiʻi 2003, pp. 7-8.
Web links
- Fischhaus Zepkow: Family Cassidae - Helmet snails
- Underwater Kwajalein: Cassis cornuta (Linnaeus, 1758) , catching prey , with egg clutch
- Cassidae - Helmet and bonnet shells (identification key for the helmet snails , English, on the FAO website ), p. 534: Cassis cornuta (Linnaeus, 1758). From: JM Poutiers: Gastropods . In: Kent E. Carpenter, Volker H. Niem (Eds.): FAO Species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 1: Seaweeds, corals, bivalves and gastropods. Food and Agriculture Organization of the United Nations, Rome, 1998.