Thais (genus)

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Thais
One Thais bronni and two Thais clavigera with egg capsules, Miura Peninsula, Kanagawa, Honshu, Japan

One Thais bronni and two Thais clavigera with egg capsules, Miura Peninsula , Kanagawa, Honshu, Japan

Systematics
Order : Sorbeoconcha
Subordination : Hypsogastropoda
Partial order : New snails (Neogastropoda)
Superfamily : Muricoidea
Family : Spiny snails (Muricidae)
Genre : Thais
Scientific name
Thais
Röding , 1798

Thais is the name of a species-rich genus of mostly medium-sized snails from the family of spiny snails that live in tropical and subtropical seas around the world.

features

The medium-sized to fairly large, mostly thick-walled, double-cone-shaped housings of the Thai species usually have a pronounced sculpting, which can consist of longitudinal ribs, furrows, knots or blunt spines at the intersections of the longitudinal and transverse ribs. Unlike the Nucella species, they do not have a thickened edge of the mouth and do not form teeth there, but in some species there can be a single sting. The operculum is horny.

The snails have a small foot that does not protrude over the edge of the shell. The eyes are on the outside of the antennae, about one-third the length of the antennae from the base. The accessory drilling organ (ABO), an acid gland for dissolving lime, is located in Thais , unlike in Nucella but just like in Purpura and Rapana , above the mucus-producing gland on the foot.

The snails are separate sexes with internal fertilization. The eggs are laid in mostly yellowish, more or less bottle-shaped egg capsules, each containing several hundred eggs. These develop into Veliger larvae, which hatch after a few weeks and go through a pelagic phase lasting several months , during which they feed on plankton. Finally, the metamorphosis into a snail takes place on the ground . Among other things, this criterion is used to distinguish the genus from Nucella .

Occurrence and way of life

The Thais snails live in tropical waters of all three great oceans, most species in the Indo-Pacific . The snails are usually found on rocky ground in the area directly below the intertidal zone. They feed on barnacles , clams and snails . A hole is drilled into the shell of the prey with the radula under the action of the acid of the ABO. It is known from Thais haemastoma that the proboscis does not fit through the hole, which is significantly smaller than that of Nucella . Rather, this injects a secretion into the hypobranchial gland located next to the rectum, which paralyzes the prey and relaxes the sphincter muscle. This opens the shell of the victim, which can now be eaten.

History of the system

The generic name Thais is first mentioned in 1798 by Peter Friedrich Röding in the catalog of the Conchyliensammlung of Joachim Friedrich Bolten with 10 species. For a long time this genus name was meaningless, because the snails were placed by Jean-Baptiste de Lamarck in 1822 in the genus with the older name Purpura Bruguière in 1789, which comprised over 50 species. It was not until the middle of the 20th century that the names of Röding - Thais , Drupa and Nucella - became important again. However, it caused confusion that the Nucella lapillus named by Röding did not match the type of the northern purple snail Buccinum lapillus Linnaeus , so that some authors assigned the name Thais to the corresponding genus - circumboreal purple snails with direct development - to which the Nordic snail Purple snail and several species belong to the Pacific coast of North America and were named Thais lapillus , Thais emarginata , etc. by them. The Nucella theobroma mentioned by Röding there is actually the Nordic purple snail, so that its genus had to receive the oldest genus name Nucella . The generic name Thais , on the other hand, falls on purple snails in warm seas with development via a plankton-eating Veliger larva. However, none of the species names from Röding are valid anymore, rather several of them are synonymous with the type species Thais nodosa , whose specific epithet goes back to Linnaeus (original name Nerita nodosa ) . Two species names are synonyms of Purpura persica and another is a dubious name (nomen dubium).

species

According to the World Register of Marine Species, the Thais genus includes the following species:

Subgenus Thais (Mancinella) Link, 1807
Subgenus Thais ( Neorapana ) Cooke, 1918
Subgenus Thais ( Thais ) Röding, 1798
Subgenus Thais ( Thaisella ) Clench, 1947
Subgenus Thais ( Thalessa ) H. & A. Adams, 1853
Subgenus Thais ( Vasula ) Mörch, 1860

Other species according to ITIS , the Indo-Pacific mollusc database OBIS and the database of marine mollusks of the Western Atlantic (Malacolog) are:

Individual evidence

  1. ↑ G. Thomas Watters, Ohio State University: Digital Murex - Thais Röding, 1798 ( memento of the original from July 19, 2010 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.biosci.ohio-state.edu archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
  2. ↑ KS Tan, JB Sigurdsson (1996): Two new species of Thais (Mollusca: Neogastropoda: Muricidae) from peninsular Malaysia and Singapore, with notes on T. tissoti (Petit, 1842) and T. blandfordi (Melvill, 1893) from Bombay , India ( Memento of the original from November 25, 2015 in the Internet Archive ) Info: The @1@ 2Template: Webachiv / IABot / www.aseanbiodiversity.info archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 971 kB) . The Raffles Bulletin of Zoology 44 (1), pp. 77-107.
  3. ^ German translation of the term ABO (accessory boring organ) in: Cleveland P. Hickman, Larry S. Robert, Allan Larson, Helen l'Anson, David J. Eisenhour: Zoologie . Translated from the English by Thomas Lazar. German adaptation by Wolf-Michael Weber. Pearson Germany, Munich 2008. 1347 pages. P. 510.
  4. ↑ a b Melbourne R. Carriker (1981): Shell penetration and feeding by naticacean and muricacean predatory gastropods: a synthesis (PDF; 12.5 MB) . Malacologia 20 (2), pp. 403-422.
  5. ↑ a b J. H. Crothers (1985), p. 341f.
  6. ↑ a b K. S. Tan, JB Sigurdsson (1990): A new species of Thais (Gastropoda: Muricidae) from Singapore and peninsular Malaysia (PDF; 541 kB) . The Raffles Bulletin of Zoology 38 (2), pp. 205-211.
  7. ↑ Peter Friedrich Röding (1798): Museum Boltenianum, sive, Catalogus cimeliorum e tribus regnis naturae quae olim collegerat Joa. Fried. Bolten : pars secunda continens conchylia sive testacea univalvia, bivalvia et multivalvia . Trappi, Hamburg, viii. + 199 pp. Reprinted by British Museum , London 1906. Page 130, Thais. 1. Clavicula depressa. Me short spindle. 1681 1 T. Lena. The cupler. Gmel. Murex fucus. 1682 2 T. meretricula. The joy girl. Gmel. Murex fucus. 2. Clavicula elevata. With protruding spindle. 1683 3 T. Parula. The wide mouth. Gmel. Buccinum parulum. 1684 4 T. Persica. The poker. Gmel. Buccinum persicum. 1685 5 T. Panama. The Panama Gmel. Buccinum haemastoma. 1686 6 T. Grisea. The pale gray wide mouth. Gmel. Buccin. haemastoma. 1687 7 T Metallica. The metal horn. Gmel. Buccin. haemastoma. 1691 8 T. Stellata The zipped metal horn. Gmel. Buccin. haemastoma. 1692 9 T. Nebulosa. The dark metal horn. Gmel. Buccin. haemastoma. 1693 10 T. Monoceros. The Unicorn. Gmel. Buccin. monodon .
  8. ↑ a b World Register of Marine Species , Thais Röding, 1798
  9. ↑ OBIS: Thais
  10. ↑ Malacolog: Thais

Web links

Commons : Thais  - collection of pictures, videos and audio files