Thais (gastropod)

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

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

Features

The medium-sized to fairly large, usually thick-walled, double- cone- shaped housing of the Thai - types usually have a pronounced sculpting that can exist at the intersections of longitudinal and transverse ribs of longitudinal ribs, ridges, nodules or blunt spines. Unlike the Nucella species they do not have thickened mouth rim and where they form no teeth, in some species, it may here give but a single sting. The operculum is horny.

The screw having a small foot that does not protrude over the edge of the housing. The eyes are located on the outside of the sensor, about one third of probe length from the base. The accessory bore organ (Abo), a gland acid for dissolving lime, is at Thai, unlike Nucella but as with purpura and rapana above the mucous -producing gland at the base.

The snails are dioecious with internal fertilization. Eggs are laid in mostly yellowish, more or less flask-shaped egg capsules, each containing several hundred eggs. These develop into veliger larvae, which hatch after a few weeks and go through several months of pelagic phase during which they feed on plankton. Finally, at the bottom of the metamorphosis takes place the stuffing. Among other things, this criterion is the genus of Nucella is deferred.

Occurrence and life

The snails of the genus Thais live in tropical waters of all three major oceans, most species in the Indo-Pacific. One finds the most snails on rocky ground in the area directly below the intertidal zone. They feed on barnacles, mussels and snails. In the shell of the prey is drilled with the radula under the action of the acid of the ABO a hole. Of Thai haemastoma is known that the proboscis does not fit through the hole, which is much smaller than for example in Nucella. Rather, a secretion of the located next to the rectum Hypobranchialdrüse is injected through this that paralyzes the prey and relaxes the sphincter. So opens the shell of the victim, which can be eaten now.

History of systematics

The genus name Thais is first mentioned in 1798 by Peter Friedrich Röding in the catalog of Conch Collection of Joachim Friedrich Bolten with 10 species. For a long time this genus name was meaningless, because the snails were provided by Jean -Baptiste de Lamarck in 1822 in the class with the older name Purpura Bruguiere in 1789, which included about 50 species. Thais, Drupa and Nucella - - was split only when that mid-20th century in more than one class, the names of Röding were again important. Some confusion, however, ensured that the figure provided by Röding Nucella lapillus did not agree with the type of the Nordic Purpurschnecke Buccinum lapillus Linnaeus, so that some authors the name Thais to the appropriate genre - was awarded to the Nordic - circumboreale Snails with direct development purple snail and several species on the Pacific coast of North America and include the name Thais lapillus, Thais emarginata were so of them etc.. In Nucella theobroma just mentioned there of Röding but it is in fact the Nordic purple snail, so that its genus the oldest genus name had to get Nucella. The genus name Thais, however, falls on purple snails of warm seas with development of a plankton -feeding veliger larva. However, of the style name of Röding is no longer valid, but several of these are with the type species Thais nodosa, whose epithet goes back to Linnaeus (original name Nerita nodosa ), synonymized. Two species names are synonyms of Purpura persica and another a dubious name ( nomen dubium ).

Species

According to the World Register of Marine Species belonging to the genus Thais include the following types:

• Thais aculeata Deshayes & Milne -Edwards, 1844
• Thais ambustulatus Hedley, 1912
• Thais bitubercularis ( Lamarck, 1822)
• Thais blanfordi ( Melvill, 1893)
• Thais cingulifera (Linnaeus, 1758)
• Thais echinulata ( Lamarck, 1822)
• Thais intermedia ( Kiener, 1835)
• Thais lacera (Born, 1778)
• Thais mancinella Linnaeus
• Thais sacellum ( Gmelin, 1791)
• Thais savignyi ( Deshayes, 1844)
• Thais tricolorata Bozzetti, 2010
• Thais wutingi Tan, 1997

• Thais alouina ( Röding, 1798)
• Thais echinata ( Blainville, 1832)
• Thais Grossa Houart, 2001
• Thais herberti Houart, 1998
• Thais lata ( Kuroda, 1931)
• Thais marmorata ( Pease, 1865)
• Thais siro Kuroda, 1931

• Thais bimaculata ( Jonas, 1845)
• Thais callaoensis (Gray, 1828)
• Thais nodosa (Linnaeus, 1758)
• Thais speciosa ( Valenciennes, 1832)
• Thais triangularis ( Blainville, 1832)

• Thais callifera ( Lamarck, 1822)
• Thais coronata ( Lamarck, 1816)
• Thais dubia ( Schepman, 1922)
• Thais gradata ( Jonas, 1846)
• Thais javanica ( Philippi, 1848)
• Thais jubilaea Tan & Sigurdsson, 1990
• Thais Keluo Tan & Liu, 2001
• Thais kiosquiformis ( Duclos, 1832)
• Thais langi Clench & Turner, 1948
• Thais luteostoma Holton, 1803
• Thais malayensis Tan & Sigurdsson, 1996
• Thais mariae Morettes, 1954
• Thais pinangensis Tan & Sigurdsson, 1996
• Thais rufotincta Tan & Sigurdsson, 1996
• Thais tissoti ( Petit, 1852)

• Thais deltoidea ( Lamarck, 1822)
• Thais tuberosa ( Röding, 1798)
• Thais tumulosa ( Reeve, 1846)
• Thais virgata ( Dillwyn, 1817)

• Thais melones ( Duclos, 1832)

Other types according to ITIS, the Indo-Pacific - Molluskendatenbank OBIS and the database of the marine molluscs of the western Atlantic ( Malacolog ) are:

• Thais clavigera Köster, 1858
• Thais chocolata ( Duclos, 1832)
• Thais delessertiana ( D' Orbigny, 1841)
• Thais lamellosa
• Thais orbita ( Gmelin, 1791)
• Thais rustica ( Lamarck, 1822)
• Thais savignyi ( Deshayes, 1844)
• Thais trinitatensis ( Guppy, 1869)
• Thais undata Lamarck
• Thais woodwardi ( Roxo )