Common spindle screw

from Wikipedia, the free encyclopedia
Common spindle screw
Case of Neptunea antiqua

Case of Neptunea antiqua

Systematics
Order : Sorbeoconcha
Partial order : New snails (Neogastropoda)
Superfamily : Buccinoidea
Family : Buccinidae
Genre : Neptunea
Type : Common spindle screw
Scientific name
Neptunea antiqua
( Linnaeus , 1758)
The left-handed Neptunea contraria is considered by some authors as a subspecies, hence the name as a synonym of Neptunea antiqua .
Egg capsules of the common spindle snail

The common spindle snail ( Neptunea antiqua ) is a species of snail belonging to the Buccinidae family . It is native to the North Atlantic , the North Sea and the western Baltic Sea .

features

The right-handed, whitish or yellowish, sometimes reddish-colored snail shell of Neptunea antiqua is egg-spindle-shaped and has 6 to 8 strongly arched whorls, a wide, egg-shaped mouth, yellow on the inside, and a long, slightly curved siphon channel. It is axially and spirally striped and in adult snails reaches a length of up to 20 cm and a width of up to 5 cm, sometimes even twice as much. The thread is high and has seven whorls. The body contact makes up 70 to 80% of the total height. The periostracum is thin and yellowish.

The antennae are long, distally half-thick, the eyes at the transition to the broader basal part. The Sipho does not project the active animal far from Siphonalkanal out. The foot is large, has a two-edged front edge and two small lateral horn-like projections in front. The female has the opening of the lower foot gland to produce mucus on the sole of the foot. The proboscis can be lengthened very much, about one and a half times to two and a half times as long as the housing. The operculum is ovally pointed with a terminal core.

Occurrence

The common spindle snail is found in the western Baltic Sea , the North Sea and in the Atlantic from the Biscay to the Arctic Ocean .

It lives below the intertidal zone at depths between 15 and 1200 meters, mostly on soft ground.

Life cycle

Like other new snails, Neptunea antiqua is sexually separated, with about the same number of males and females, but the females are larger. It is estimated that the snails can live to around 17 years. In the Irish Sea , sexual maturity is reached by males with a shell length of 7.5 to 9 cm at the age of 4 to 5 years, while females only reach sexual maturity with a shell length of 9.5 to 11 cm at the age of 6 to 9 years. In the Skagerrak the males are sexually active with a casing length of about 5 to 6 cm, the females with 8 cm. The male mates with the female with his penis . A female needs about 21 days in the months of February to April to lay an average egg clutch with 37 egg capsules, i.e. 1.8 capsules per day. Sexual intercourse still takes place during the egg-laying period, with a female usually having several sexual partners. To lay eggs at greater depths on sandy bottom, many snails come and stay together for several weeks, and the egg clutches are usually attached to the shell of another living common spindle snail. The mother does not eat while laying eggs, lays more than half of her own volume and is severely weakened after the last egg capsule has been laid. In the aquarium, 8 out of 9 females died within 3 months of laying eggs.

An egg capsule contains about 1 to 4 larger, viable eggs, which are supplied by up to 2500 smaller eggs. The development of the Veliger stage takes place in the egg capsule, so that after about half a year, from the beginning of August to the end of October (in the Irish Sea to January), finished snails hatch. During studies in the Irish Sea, clutches with 14 to 84 egg capsules hatched 63 to 78 juvenile snails. This roughly corresponds to the ratios in other Neptunea species, where an average of 1 to 3.5 snails develop per capsule. According to measurements in the Öresund, the freshly hatched snails have a shell length of around 6 mm, in the Irish Sea around 8 mm and in the Skagerrak up to 12 mm. Young animals kept in the aquarium for one year had at least 2 to 3 cm long housings.

nutrition

Common spindle snails are carnivores. The most important prey animals are mussels , to a lesser extent polychaetes and decapods . Locally other species are the main prey, e.g. B. Priapulus caudatus , a priap worm , in Millport .

In experiments in the aquarium, common spindle snails did not react to bait with fresh mussel meat, unlike net litter snails and whelks . Among the polychaetes they did not attack Sabella pavonina , but ate many bristles of the genera Ophelia , Lumbriconereis , Stylarioides and Amphitrite . Each day they ate around 1 percent of their own weight on live ophelia worms, which took around 40 to 70 hours to pass through the intestinal tract. From this it is concluded that common spindle snails eat less, digest more slowly and grow less quickly than net snails and whelk snails.

Exposure to imposex

Similar to other snails, the common spindle screw has been threatened since the early 1970s by the water pollution with tributyltin (C 4 H 9 ) 3 SnH, which leads to the formation of male sexual organs in female snails. These females, affected by the so-called imposex , can no longer lay eggs. According to studies from 2003, the common spindle snail is even more sensitive than the whelk , but the greatest pollution is on the Dutch coast and in the German Bight, where the water is very mixed, while in the deep water of the Skagerrak , where there is stratification of the water , despite the heavy shipping traffic above, healthy populations of Neptunea antiqua still live.

Individual evidence

  1. ↑ According to the World Register of Marine Species recognized species Neptunea contraria (Linnaeus, 1771)
  2. ↑ CM Howson, BE Picton (ed.): The species directory of the marine fauna and flora of the British Isles and surrounding seas . Ulster Museum Publication, 276. The Ulster Museum, Belfast 1997. ISBN 0-948150-06-8 . vi, 508 pages.
  3. ↑ a b c Jack B. Pearce, Gunnar Thorson (1967): The feeding and reproductive biology of the red whelk, Neptunea antiqua (L.) (Gastropoda, Prosobranchia) . Ophelia 4 (2), pp. 277-314. doi : 10.1080 / 00785326.1967.10409624
  4. ↑ a b A.J. Power, BF Keegan (2001): Seasonal patterns in the reproductive activity of the red whelk, Neptunea antiqua (Mollusca: Prosobranchia) in the Irish Sea . Journal of the Marine Biological Association of the United Kingdom 81 (2), pp. 243-250.
  5. ^ Gunnar Thorson (1946): Reproduction and larval development of Danish marine bottom invertebrates; with special reference to the planktonic larvae in the Sound (Øresund) . Meddelelser fra Kommissions for Danmarks Fiskeri- og Havundersøgelser. Series Plankton 4 (1), pp. 1–523. On Neptunea antiqua : p. 227, p. 430.
  6. ↑ KR Smith, RA McConnaughey, CE Armistead (2011): Benthic Invertebrates of the Eastern Bering Sea: A Synopsis of the Life History and Ecology of Snails of the Genus Neptunea (PDF; 8.7 MB) . NOAA Technical Memorandum NMFS-AFSC-231. US Department of Commerce. 59 pages. Tab. 3, p. 37.
  7. ↑ John D. Taylor (1978): The diet of Buccinum undatum and Neptunea antiqua (Gastropoda: Buccinidae) . Journal of Conchology 29, p. 309.
  8. ↑ CC Hallers-Tjabbes, JW Wegener, BA van Hattum, JF Kemp, E. ten Hallers, TJ Reitsemae, JP Boon (2003): Imposex and organotin concentrations in Buccinum undatum and Neptunea antiqua from the North Sea: relationship to shipping density and hydrographical conditions . Marine Environmental Research 55 (3), pp. 203-233. PMID 12688240

literature

  • Peters S. Dance (Ed.): The great book of sea shells. Snails and mussels of the world's oceans. German edited by Rudo von Cosel, Verlag Eugen Ulmer, Stuttgart 1977, ISBN 3-8001-7000-0
  • John D. Fish, Susan Fish: A Student's Guide to the Seashore . Cambridge University Press, Cambridge 2011. 540 pages. Neptunea antiqua (Linnaeus) , p. 234.

Web links

Commons : Neptunea antiqua  - collection of images, videos and audio files