Conus

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Conus
Striped cone snail (Conus striatus)

Striped cone snail ( Conus striatus )

Systematics
Order : Sorbeoconcha
Subordination : Hypsogastropoda
Partial order : New snails (Neogastropoda)
Superfamily : Conoidea
Family : Cone snails (Conidae)
Genre : Conus
Scientific name
Conus
Linnaeus , 1758

Conus is the name of a marine species of snail . With over 600 recognized species, it is the most species-rich genus of the family of cone snails .

distribution

The genus Conus is found in the tropical and subtropical seas. The genus reaches the greatest biodiversity in the western Indo-Pacific . There are only a few species in moderate latitudes, such as on the coast of South Africa , in the Mediterranean ( Mediterranean cone ) and on the coast of Southern California ( Conus californicus ). It is not represented in Central Europe. The conus species colonize different habitats from the coastal area to deeper zones, on sand, rocks or coral reefs.

features

The cone snails of the genus Conus have a largely conical housing with a smooth central spindle (Columella) and an elongated, narrow, straight, imperforate mouth. At the top of this conus , from which the siphon protrudes, is the head of the snail. At the rear, wide end of the housing, the passages of the thread protrude so that they approximately form a strongly flattened second cone. The horny operculum is small.

The species of the genus Conus vary greatly in terms of size, color and pattern. The largest species reach 23 cm in length. Since there is also great variability within many Conus species, many synonyms have been described. In 2009 there were 3200 different species names of this genus, with around 16 new species being described each year. Over 600 species are recognized.

Development cycle

Cone snails are separate sexes. The male has an extendible penis . The female has a gland on the foot with which the egg capsules are formed. The eggs reach the opening of this gland via the foot. The egg capsules are attached to a solid base. Depending on the species and individual, 40 to 11,400 eggs were counted in an egg capsule. Most of the eggs develop into larvae and there are no food eggs. In the egg capsule, the trochophora stage is reached after 2–6 days, the Veliger stage after 6–10 days. The Veliger larvae hatch after about 2 weeks. In the laboratory they do not survive for more than 9 days. In the case of Conus pennaceus , metamorphosis occurs on the first day after hatching . The radula of the resulting juvenile snails differs from that of adult snails.

Conus marmoreus with a captured cowrie snail Monetaria caputserpensis
Conus striatus with a captured fish

food

All conus species, like the other cone snails and other arrow tweers ( Conoidea ), are predatory and kill their prey with poison that is injected using harpoon-like radula teeth . Prey in the vicinity is chemically perceived through the osphradium , which is particularly highly developed in cone snails. In contrast to live prey, carrion did not trigger any search reactions in the cone snails examined. A fang is only used once. After an unsuccessful attack it is repelled, otherwise it is swallowed with the prey. Like other dart-tailed snails, most of the conus species feed on polychaetes , e.g. B. Conus ebraeus , others from acorn worms , e.g. B. Conus quercinus . In the genus Conus , however, there are also a number of species that specialize in mollusks or fish as prey. These species have particularly fast-acting poisons so that the prey can no longer move away. The fish-eating species include Conus striatus , Conus catus , Conus purpurascens , Conus tulipa , Conus magus and Conus geographus and, as the only species in the Atlantic, Conus ermineus , the snail-eating Conus marmoreus and Conus textile . Adult cone snails are usually relative food specialists, but the range of prey can change over the course of life. In the case of Conus magus , it was observed that young animals that are still too small to hunt fish eat small polychaetes, while in adults the prey consists of fish. The shape of the harpoons changes in the course of life. While the teeth of juveniles still resemble those of vermivorous cone snails, in adulthood they are adapted to hunting fish. Piscivore cone snails also differ from vermivore in that the relatively large prey is pre-digested in the foregut, as it can only then get into the rear sections of the intestine located inside the snail shell.

Enemies

Eggs and larvae fall prey to fish, other potential enemies for young animals are starfish and brittle stars . Adult cone snails have few enemies. They defend themselves against these with the help of their poisonous harpoons, including people. Due to broken snail shells, it is believed that some species of fish, such as parrot fish and moray eels, chase the snails. Starfish ate cone snails in laboratory experiments only in exceptional cases, while Triton snails of the genus Cymatium repeatedly preyed on cone snails.

Systematics

Until 2009, the more than 600 cone snail species within the monogeneric family Conidae were placed in a single genus Conus . Christopher Meyer and Alan Kohn began with molecular genetic studies to clarify the phylogeny. These studies and the debate about the systematics are ongoing. In 2009, JK Tucker and MJ Tenorio suggested 3 different families and 82 genera for the recent cone snails on the basis of morphological and molecular genetic studies. Other malacologists continue to advocate a single genus Conus within the Conidae family. Puillandre, Duda, Meyer, Olivera and Bouchet, on the other hand, advocate a systematics with four genera in 2015, in which the majority of the species - around 85% - still belong to the genus Conus with 57 subgenera, but Conasprella with 11 subgenera and Profundiconus each with a dozen Species as well as the monotypical Californiconus come, as can be found in the World Register of Marine Species . The proposed species names in 68 subgenera are accepted as alternative names.

species

According to the World Register of Marine Species , the genus Conus includes 748 species in a broader sense :

Subgenera

According to the World Register of Marine Species , the genus Conus includes 57 subgenera :

The following names of sub-genera were synonymous :

  • Conus (Coronaxis) Swainson, 1840 is Conus (Conus) Linnaeus, 1758
  • Conus (Ongoconus) da Motta, 1991 is Conus (Splinoconus) da Motta, 1991
  • Conus (Spuriconus) Petuch, 2003 is Conus (Lindaconus) Petuch, 2002
  • Conus (Strioconus) Thiele, 1929 is Conus (Pionoconus) Mörch, 1852
  • Conus (Theliconus) Swainson, 1840 is Conus (Hermes) Montfort, 1810 (objective synonym)

literature

  • Dieter Röckel, Werner Korn, Alan J. Kohn: Manual of the Living Conidae Vol. 1: Indo-Pacific Region . Verlag Christa Hemmen, Wiesbaden 1995. The texts on the individual cone snail species of the Indo-Pacific are published on The Conus Biodiversity website with the permission of the authors (see web links).

Individual evidence

  1. ↑ a b c Conus Linnaeus, 1758 ( World Register of Marine Species ).
  2. ^ MJ Tenorio, AJ Monteiro (2008): The Family Conidae. The South African species of Conus. GT Poppe, K. Groh (eds): A Conchological Iconography. Hackenheim: ConchBooks.
  3. ↑ GM Branch, CL Griffiths, ML Branch, LE Beckley, (2010): Two oceans: a guide to the marine life of Southern Africa. Cape Town: Struik Nature. ISBN 978-1-77007-772-0 .
  4. ^ AJ Monteiro, MJ Tenorio, GT Poppe (2004): The Family Conidae. The West African and Mediterranean species of Conus. In: GT Poppe, K. Groh (eds): A Conchological Iconography. Hackenheim: ConchBooks.
  5. ^ MJ Tenorio, JK Tucker, HW Chaney (2012): The Families Conilithidae and Conidae. The Cones of the Eastern Pacific. In: GT Poppe, K. Groh (eds): A Conchological Iconography. Hackenheim: ConchBooks.
  6. ^ The Conus biodiversity website
  7. ^ A b Alan J. Kohn (1994): Ecology of Conus in Hawaii . In: E. Alison Kay (ed.): A Natural History of the Hawaiian Islands: Selected Readings II. 210-254.
  8. ↑ a b c d Alan J. Kohn (1956): Piscivorous gastropods of the genus Conus. Proceedings of the National Academy of Sciences, 42 (3), 168-171. PMC 528241 (free full text)
  9. ↑ Robert Nordsieck (weichtiere.at): The venom apparatus of the cone snails (Conidae)
  10. ^ The Conus Biodiversity Website: Conus tulipa Linnaeus, 1758
  11. ↑ a b J. Nybakken, F. Perron (1988): Ontogenetic change in the radula of Conus magus. Marine Biology 98, 239-242.
  12. ^ JA Rivera-Ortiz, H. Cano, F. Marí: Intraspecies variability and conopeptide profiling of the injected venom of Conus ermineus. In: Peptides. Volume 32, number 2, February 2011, ISSN  1873-5169 , pp. 306-316, doi : 10.1016 / j.peptides.2010.11.014 , PMID 21126547 , PMC 3619394 (free full text).
  13. ↑ http://penelope.uchicago.edu/~grout/encyclopaedia_romana/aconite/geographus.html
  14. ↑ http://penelope.uchicago.edu/~grout/encyclopaedia_romana/aconite/marmoreus.html
  15. ↑ http://www.underwaterkwaj.com/shell/cone/Conus-textile.htm
  16. ↑ Interview with Professor Alan Kohn, Professor Emeritus, Zoology ( Memento of the original from February 27, 2012 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.seashell-collector.com
  17. ↑ JK Tucker, MJ Tenorio (2009): Systematic Classification of Recent and Fossil Conoidean Gastropods. ConchBooks, Hankenheim 2009.
  18. ↑ P. Bouchet, Yu.I. Kantor, A. Sysoev, N. Puillandre (2011): A new operational classification of the Conoidea. Journal of Molluscan Studies 77, 273-308.
  19. ↑ N. Puillandre, TF Duda, C. Meyer, BM Olivera, P. Bouchet (2015): One, four or 100 genera? A new classification of the cone snails. Journal of Molluscan Studies 81, pp. 1-23.
  20. ^ Conidae J. Fleming, 1822. World Register of Marine Species . Classification: Traditionally, all cone shells have been included in the Linnaean genus Conus. Tucker & Tenorio (2009) have recently proposed an alternative shell- and radula-based classification that recognizes 4 families and 80 genera of cones. In WoRMS, we currently still recognize a single family Conidae (following Puillandre et al. 2011), but Tucker & Tenorio's 80 genera classification is presented as "alternative representation". [P. Bouchet, Aug. 14, 2011]

Web links

Commons : Conus  - collection of images, videos and audio files