Mutable head shield snail
| Mutable head shield snail | ||||||||||||
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Variable head shield snail ( Chelidonura varians ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Chelidonura varians | ||||||||||||
| Eliot , 1903 |
The variable headshell snail ( Chelidonura varians ) is a species of snail from the order of the headshell snail (Cephalaspidea) and the family Aglajidae , which is widespread in the Indo-Pacific .
features
The variable head shield snail, which is typically around 3 cm long and 1 cm wide, but sometimes up to 7 cm long, has a deep black color with bright blue edges towards the parapodia , dorsal shields and posterior processes. However, this blue line is interrupted in places, while another blue line runs along the middle of the head shield and there may be individual bruises in other parts of the body. The parts of the body hidden under the parapodia are slightly lighter than the rest of the body. The head shield has an approximately 1.8 cm long sail that tapers towards the back and is of variable shape, often with the outline of an isosceles triangle. The posterior processes are about 4 to 5 mm long. The gill and the sperm groove are white. Numerous bluish-white elevations with irregularly grouped bristles sit on both sides of the mouth and under the extensions of the head shield. The rather small pharynx is about 3 mm wide and moderately muscular. This is followed by a narrow intestinal tube that runs through the midgut gland without expanding into a stomach or the like. The prostate is granular and deeply forked. The brown, very thin-walled snail shell of Chelidonura varians has the shape of an ax.
distribution
The species is found in the Indo-Pacific , but not in the Red Sea , on coral reefs , where its prey is also common.
Life cycle
Like other headshell snails, the mutable headshield snail is a hermaphrodite , in which - unlike some other species of the family - two individuals mate with their penises . The disc-shaped clutches, in which the eggs are in individual capsules, are attached to a hard or sandy substrate with a single thread of mucus. A few days after oviposition, Veliger larvae hatch . Their diet and development time are still unknown.
food
As a food specialist, Chelidonura varians feeds on the Acoela species, Convolutriloba retrogemma , whose individuals are completely devoured.
Aquarium keeping
Chelidonura varians is traded as a predator of the Convolutriloba retrogemma , which is undesirable in marine aquariums . However, once the snails have eaten all the worms, they will starve to death because they will not take any other food.
Web links
Individual evidence
- ^ Charles NE Eliot : Notes On Some New Or Little-Known Members Of The Family Doridiidæ. In: Proceedings of the Malacological Society of London. Vol. 5, No. 5, 1903, pp. 331-337, here p. 305, doi : 10.1093 / oxfordjournals.mollus.a066000 .
- ↑ Nils Anthesa, Nico K. Michiels: morphology Reproductive, mating behavior, and spawning ecology of cephalaspid sea slugs (Aglajidae and Gastropteridae). In: Invertebrate Biology. Vol. 126, No. 4, 2007, pp. 335-365, doi : 10.1111 / j.1744-7410.2007.00096.x .
- ↑ David W. Behrens: Nudibranch Behavior. New World Publications, Jacksonville (Florida) 2005, ISBN 1-878348-41-8 , p. 99.
- ↑ Planariums or turbellariums - pests in the reef aquarium. Part 1. Retrieved July 16, 2020.