Poiretia (Spiraxidae)
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Housing of Poiretia cornea , Naturalis , Leiden |
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| P. Fischer , 1883 |
Poiretia is a genus of predatory land snails native tothe Mediterranean basin thatetch holes in the shells of their captured snails. Thefive Poiretia speciesare theonly genus of the Spiraxidae family tobe foundin Europe and North Africa .
Features and way of life
The whitish to brownish-yellow shells of the Poiretia species are twisted to the right and have a slender, spindle-shaped shape so that the predatory snails can crawl through relatively narrow gaps. In adult snails they have 5 to 7 whorls, no umbilicus, clear growth stripes and a housing mouth that tapers towards the apex and takes up about half the length of the housing. The snails themselves are slender and, like the shells, usually brownish to yellowish in color with lighter soles and margins. The skin surface is granular, the upper antennae about twice as long as the lower. The genital organs are simple and vary little. The radula has numerous long, slightly curved, pointed single-pointed teeth.
The mucus secreted by the suprapedal gland (at the front end of the foot) contains acid which is used to etch holes in the shell of captured snails, allowing the predatory snail to reach the meat of the prey. This is crushed with the help of the powerful radula. The preferred prey of these predatory snails include land snails , which can protect themselves from attack by other predators with their operculum . The shells of the eaten snails can be recognized by the characteristic etched large holes. Studies by Helwerda (2015) on Poiretia dilatata and Poiretia compressa indicate that not only the mucus of the suprapedal glands, but also of the plantar glands is acidic and can therefore etch large areas of holes, while the predatory snail remains motionless with its foot for up to two days the house of the prey snail sits. It was also observed that only in terrestrial snails holes were etched and other prey snails were pulled out via the housing mouth with the help of the radula. The radula is also obviously not involved in perforating the shell. Both Poiretia cornea and Poiretia algira have also been observed eating earthworms that were longer than the predators. The radula quickly penetrates the worm's interior and transports its internal organs into the snail's mouth, which - unlike in Daudebardia , for example - leads to the rapid death of the victim.
Like other land snails, the predatory snails of the genus Poiretia are hermaphrodites , with two snails fertilizing each other. The embryos develop into finished snails in the egg shells.
The five Poiretia species, their occurrence and their distribution
Predatory snails of the genus Poiretia occur both in forests and in landscapes with little wood to the north and south of the Mediterranean . While Poiretia algira is native to the area of the Mediterranean coast of Algeria , of the other four species only the Dalmatian predator snail ( Poiretia cornea ) also occurs in North Africa, more precisely Libya , which may have been introduced by humans. The rest of the distribution area of the Dalmatian predator snail includes the karst landscapes of the Dinaric Mountains along the Adriatic coast from northeastern Italy to southern Albania . Poiretia compressa , on the other hand, occurs from southern Greece including the Ionian Islands to southern Albania, Poiretia delesserti from northwestern Greece to central Albania and the Sicilian predatory snail ( Poiretia dilatata ) in southwestern Greece and southern Italy including Sicily .
History of systematics, external systematics
In 1792, Jean-Guillaume Bruguière was the first to describe one of the snail species now belonging to the genus Poiretia under the name Bulimus algirus . Paul Henri Fischer already knew the predatory character of this snail and in 1883 assigned it as Glandina algira to the predator snail genus Glandina and within it to the subgenus Poiretia , which differs from other species of the genus Glandina in the weak development of the labial palps (cf. Rosy wolf snail , then Glandina rosea , with very large labial palps). In honor of Jean Louis Marie Poiret, Fischer chose the homonymous name Poiretia P. Fischer , that of Étienne Pierre Ventenat as early as 1807 for the plant genus Poiretia Vent, which belongs to the butterfly family . had been assigned, so that hemihomonyms are here - identical names for a plant and an animal species.
According to the system of Bouchet and Rocroi (2005), Poiretia belongs to the subfamily Euglandininae Baker , 1941, which was counted to the family Oleacinidae with two other subfamilies - Oleacininae Adams & Adams , 1855 and Varicellinae Baker , 1941 . Thompson (2010), however, places the Euglandininae - like Baker 1962 - among the Spiraxidae . Not all authors share this opinion; Helwerda (2015), for example, still adheres to the systematics according to Bouchet and Rocroi, i.e. belonging to the Oleacinidae.
literature
- P. Fischer , P. Œhlert, SP Woodward: Manuel de conchyliologie et de paleontologie conchyliologique ou histoire naturelle des mollusques vivants et fossiles suivi d'un appendice sur les brachipodes. Avec 23 planches contenant 600 figures et 1138 gravures dans le texte . Pp. 1–24, 1–1369 (1-6), p. 452, plates 1–23, map 1. Savy, Paris 1887.
- Renate A. Helwerda (2015): Predatory Poiretia (Stylommatophora, Oleacinidae) snails - histology and observations . Vita Malacologica 13, pp. 35-48.
- Fred G. Thompson (2010): Four species of land snails from Costa Rica and Panama (Pulmonata: Spiraxidae) . Revista de Biología Tropical (International Journal of Tropical Biology and Conservation) 58 (1), pp. 195-202.
- HB Baker (1962): Puerto Rican oleacinoids . The Nautilus 55, pp. 24-30.
- HB Baker (1941): Some Haplotrematidae . The Nautilus 54, pp. 130-136.
- Philippe Bouchet, Jean-Pierre Rocroi: Part 2. Working classification of the Gastropoda . Malacologia, 47: 239-283, Ann Arbor 2005, ISSN 0076-2997 .
Web links
- F. Welter Schultes: Genus taxon summary for Poiretia Fischer, 1883 . AnimalBase, SUB Goettingen. Species overview .
- The diet of snails II: Carnivorous land snails . The Dalmatian predatory snail ( Poiretia cornea ) on Weichtiere.at
Individual evidence
- ↑ Alexey Shipunov: The problem of hemihomonyms and the on-line hemihomonyms database (HHDB) . Bionomina, 4: 65-72 (2011). Download PDF