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Stilifer linckiae parasitizes on Linckia multifora |
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| Broderip & Sowerby I , 1832 |
Stilifer is the name of a genus of snails from the Eulimidae family, the 15 species of which live as endoparasites in the galls they induce in the skin of starfish .
features
The parasites of the genus Stilifer have an egg-shaped or spherical, inflated, translucent, thin-walled, smooth and shiny shell , which is sculptured with growth lines and sometimes spiral stripes. The thread has numerous whorls and a pointed, sometimes bent apex with a pointed protoconch . The body is rounded in shape. The case mouth is crooked and almost ovoid.
The females of some Stilifer species, including Stilifer linckiae , have antennae, but all males lack them. All species have a rudimentary foot, but no operculum . The worms of both sexes also have a real coat including mantle cavity with a gill , eye-catching black eyes , otoliths and for prosobranch typical nervous system.
The anatomy of the Stilifer snails is shaped by their way of life as endoparasites in the skin of starfish, in which they trigger the formation of spherical galls dented into the host's body cavity. The inside of the bile is lined by tissue of the parasite snail, which also envelops the entire snail including the housing and only leaves an opening through the skin at the top, where the apex of the snail shell is also located. This shell is also referred to as the pseudopallium or pseudopallium and is considered to be homologous to the pseudopod of the ectoparasitic snails of the genus Thyca. As with this one, there is also an opening at the base of the mantle through which the snail introduces its proboscis into the starfish tissue in order to suck up the host's body fluids. In Stilifer utinomi , the proboscis is about five times as long as the snail shell.
The gall with Stilifer snails are usually clearly recognizable by the starfish, but the parasite compared to the host very small, only the opening to see protrudes slightly from the sometimes the apex of the snail shell.
Development cycle
The snails are first males and then females, but they remain males when a female is around. This means that on a starfish there are usually galls with males and females next to each other. The male's penis is long enough to mate with the neighboring or neighboring females. These lay egg capsules with at Stilifer utinomi about 100 microns large eggs to likely plankton -eating Veliger developing larvae. When these settle on a starfish and metamorphose , they have a shell about 350 µm high. The Protoconch with the slowly increasing whorls differs significantly from the Teleoconch, in which the whorls increase faster, and is separated from it like a scar.
species
The following species of snail belong to the genus Stilifer :
- Stilifer akahitode , Habe & Masuda, 1990
- Stilifer astericola , Broderip, 1832 (in Heliaster cumingi , Galapagos Islands)
- Stilifer barroni , A. Adams, 1854
- Stilifer birtsi , Preston, 1904
- Stilifer celebensis , Kükenthal, 1897
- Stilifer concavus , Warén, 1980
- Stilifer guentheri , Angas, 1877
- Stilifer inflatus , Warén, 1980 (in Linckia multifora and other Linckia spp., Indo-Pacific)
- Stilifer kawamurai , Habe, 1976
- Stilifer linckiae , P. Sarasin & F. Sarasin, 1887 (in Linckia multifora and other Linckia spp., Indo-Pacific, first found before Trinkomali , Sri Lanka )
- Stilifer ovoideus , H. Adams & A. Adams, 1853
- Stilifer pisum , Habe, 1953
- Stilifer quadrasi , O. Boettger, 1893
- Stilifer utinomi , Habe, 1951 (in Linckia spp., Indo-Pacific)
- Stilifer variabilis , O. Boettger, 1893
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.
- 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
Web links
Individual evidence
- ^ Broderip (in Broderip & Sowerby I), 1832. WoRMS , 2018. Accessed February 12, 2019.