Stilifer linckiae
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Stilifer linckiae parasitizes on Linckia multifora |
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| Sarasin & Sarasin , 1887 |
Stilifer linckiae is the name of a worm - type from the family of eulimidae (genus Stilifer ), as endoparasite in the skin of the comet star lives.
features
Stilifer linckiae bears an egg-shaped, thin-walled, fragile, chalky white snail shell with convex circumferences, which in adult snails reaches a length of around 6 mm and a diameter of 3 mm. In addition to the apex with the pointed protoconch, the thread consists of 5 convex, adjacent passages. The case is smooth and only sculpted with microscopic growth strips. The case mouth is approximately circular.
The snail has an extensive pseudopallium, which envelops a large part of the snail shell. Only at the uppermost point in the shell is there an opening to the outside, where the apex of the snail shell is also located, and a small opening at the base through which the proboscis is sunk into the host tissue. The snail also has a real coat , a gill , a rudimentary foot without an operculum and clearly recognizable black eyes .
Distribution and way of life
Stilifer linckiae is distributed throughout the Indo-Pacific , where its host animal, the comet star ( Linckia multifora ) also lives. It was first described on a starfish on the Sri Lankan coast off Trinkomali . The snail penetrates the lime layer of the starfish's skin with its whole body, where it triggers the formation of a spherical bile made of starfish tissue, which bulges inwards into the host's body cavity. The snail's pseudo-mantle lines the inside of the bile and only leaves an opening to the outside, from which the apex of the snail's shell sometimes protrudes. With its proboscis , which the snail bores into the starfish's tissue, it sucks in its body fluids.
The galls with the parasitic snails are mostly located in the outer part on the underside of the arms of the starfish. They are separated from the host's body cavity by the connective tissue formed by the host. There can be up to five snails in a bile, each with its own opening to the outside and one usually significantly larger than the other.
Comet stars infested by Stilifer linckiae are less prone to autotomy than healthy ones and thus find it difficult to get rid of the parasite.
Development cycle
Stilifer linckiae is first male and then female, resulting in small individuals being males and large females. The male has a long penis to mate with a neighboring female. The fertilized eggs develop into Veliger larvae in about 4 to 8 days , which after a plankton phase settle on another starfish and metamorphose into small parasites .
literature
- Paul Sarasin, Fritz Sarasin: About two parasitic snails. In: Results of scientific research on Ceylon 1884–1886. Volume 1, Issue 1. CW Kreidel, Wiesbaden 1887, pp. 21-31.
- Paulus Schiemenz: Parasitic snails. Biologisches Centralblatt 9, 1889, pp. 567-574, 585-594.
- Mattheus Marinus Schepman, HF Nierstrasz: Parasitic prosobranchs of the Siboga expedition. Siboga expeditie 49. EJ Brill, Leiden 1909.
- Thomas WM Cameron: Parasites and Parasitism. Wiley, New York 1956. pp. 199-201.
- Jørgen Lützen: Studies on parasitic gastropods from echinoderms. II. On Stilifer Broderip, with special reference to the structure of the secondary apparatus and the reproduction. Det Kongelige Danske Videnskabernes Selskab, Biologiske Skrifter 19 (6). Commission: Munksgaard, København 1972.
- E. Alison Kay: Hawaiian Marine Shells. Bishop Museum Press, 1979. p. 167.
- Anders Warén (1980): Revision of the Genera Thyca, Stilifer, Scalenostoma, Mucronalia and Echineulima (Mollusca, Prosobranchia, Eulimidae). Zoologica Scripta 9, pp. 187-210.
- Anders Warén (1983): A Generic Revision of the Family Eulimidae (Gastropoda, Prosobranchia). Journal of Molluscan Studies 49 (Supplement 13), pp. 1-96, here pp. 76-80. doi: 10.1093 / mollus / 49.Supplement_13.1
