Cube turban snail

Cube turban snail
	Five different views of the shell of the dice turban snail
Systematics
Order :	Trochida
Superfamily :	Trochoid
Family :	Top snails (Trochidae)
Subfamily :	Cantharidinae
Genre :	Phorcus
Type :	Cube turban snail
Scientific name
	Phorcus turbinatus
	( Born , 1778)

The dice turban snail ( Phorcus turbinatus ) belongs to the family of the gyro snails (Trochidae) within the superorder Vetigastropoda . The species is known by numerous synonyms, but according to recent molecular studies it belongs to the genus Phorcus and has since been used mainly under the appropriate name. It is very common throughout the Mediterranean and can even be found in the Eastern Atlantic.

The cube turban snail has a conical, solid-walled shell with six whorls. It is a typical representative of the intertidal zone of rocky coastal areas.

Appearance and characteristics

Bowl

Like all trochidae also has Phorcus turbinatus a conical shell, the mouth of which is drawn inward. Compared to other species of the family, however, it has a stronger hydrodynamic shell, which is characterized by its narrower and somewhat more compact cone shape, which means that it offers a small surface area for waves and currents. The shell also takes up 80 percent of the body's weight and is very massive. As a result, the sheer mass of the shell also prevents it from being washed away and protects against mechanical damage from the surf.

The species has a medium-sized shell with six whorls. A distinction is made between the upper mouths, which are mostly already somewhat decomposed, and the lower mouths with numerous, rounded spiral strips. The whorls are also strongly arched and the spindle base is toothed and unabelled. The spindle base has a bumpy tooth and can be gray, yellowish or greenish and covered with numerous rectangular, reddish-brown to purple spots that sometimes flow into ribbons. The lid is horny, spiral and circular. The inside of the bowl is mother-of-pearl and shimmers green.

foot

The muscular foot of Phorcus turbinatus makes up 15 percent of the soft tissue and has a deep longitudinal furrow that divides the foot in half through the entire underside of the foot. Numerous transverse canals run parallel to each other from the edge of the foot to the middle furrow. In addition, round pores of various diameters and depths cover the underside of the foot. The general biological principle of the relationship between structure and function comes into play here: the snail can fold its foot through the furrow and thus adapt its shape and size. The canals and pores allow the foot to stretch a lot. In addition, the water content in the foot can be precisely regulated, which is important for holding on to the substrate, but also for movement. These structures make the foot very elastic and this allows the snails to perform flexible movements. Even with strong surf the snails stick to the stones.

Distribution area and habitat

The snail has been registered from the eastern Mediterranean (Egypt, Israel, Lebanon) and the Aegean to the western Mediterranean, the Adriatic and North Africa even to the eastern Atlantic near Portugal and Morocco. It occurs regularly and very frequently in the Mediterranean on troubled, current-rich and rocky coasts from the intertidal zone to the flat sublittoral . In this area there is regular alternation of ebb and flow, which means that environmental factors such as temperature fluctuations, low salinity and dehydration have a major influence and thus require adjustments by the snail. The snail clings to the surface of larger rocks or crawls into holes and crevices in rocks. Due to the sometimes shallow water depth in the intertidal zone, the temperature fluctuations can be high, in summer even between 22 and 38 degrees. But since Phorcus turbinatus is exposed to constant waves and dominant northerly winds, it can easily drift to cooler places.

behavior

The dice turban snail stays on its rock during low tide and continues to eat. The animals only seek refuge under rocks and in crevices when it is very hot or stormy. In very dry conditions one can find clusters of four to seven animals. This reduces the open surface of each animal and thus also the negative influence of the high temperature, which protects against overheating. Although the snail is usually found in places with strong surf, it can handle drought very well: it can survive the hours of ebb tide because it can store water in its shell cavity and tissues. The high water content is important so that the snail can produce slime, which not only protects it from water loss, but also enables it to move on the dry ground. Even when it is completely dry, the snail is still mobile and can look for shelter.

The snail can absorb both dissolved and atmospheric oxygen, adapted to its habitat, and its rate of absorption of oxygen is very high. Nevertheless, the life expectancy of the snail without water is severely limited. In such a state of emergency shortly before death, the snail pulls its body completely back into its shell and detaches itself from its substrate. It is also insulated with a special horn cover. In this state, the snail can switch to the anaerobic state for a certain period of time and through biochemical adaptations prevent the cells from becoming too acidic .

Phorcus turbinatus , like other species of Trochidae, makes a vertical migration within the littoral zone. The short-term movements of the cube-turban snail were examined and the influence of light and gravity on these movements was tested. When exposed to darkness, the snails moved slightly upwards and slightly downwards when exposed to light. When the light was attached to the bottom of the tank instead of the top, the snails moved back up. This suggests that light is causing negative phototaxis in the cube turban snail ; the animals move away from the light. In addition, the darkness causes a negative geotaxis of the snails under natural conditions . This explains the high migration, as the animals move against the force of gravity .

nutrition

Phorcus turbinatus feeds herbivore , mainly on diatoms , unicellular algae and organic waste. To do this, she scrapes off rocks and stones. Thanks to its rasping tongue, the radula , the snail is perfectly adapted to this type of food intake. The length of the radula is 70 percent of the height of the shell and its weight is one fifth of the weight of the coat.

The presence of hemoglobin in the tissue of the radula is an important biochemical adaptation in order to be able to feed in the intertidal zone . The most intense red color due to this protein is found in the muscles of the radula. They are the most active in processing food and require the most oxygen. This need is met by myoglobin , which has a high affinity for oxygen. When the tide is out, the myoglobin accumulates in the tissue of the radula, so that in addition to the oxygen binding through the hemoglobin, additional oxygen can be absorbed. This means that the animals can eat without any problems even in the total absence of water, because their muscles have enough oxygen available.

Reproduction

The snail species is segregated and the animals spawn all year round. The sperm and many small eggs are released into the open sea water and external fertilization occurs when the gametes happen to meet. A free-swimming planktonic larva, the so-called Veliger larva, hatches, which first has to develop into an adult snail.

Use and endangerment

Phorcus turbinatus is well suited for biomonitoring because it is found in such abundance throughout the Mediterranean throughout the year. Phorcus turbinatus serves as a bio-indicator to detect heavy metals . Heavy metals are usually naturally leached from the soil and rocks into the water in small amounts. However, with developments in industry and agriculture, there is a rapid increase in environmental pollution by metals. In water these are mainly mercury, copper, zinc, lead, chromium and nickel. They end up in the ocean in large quantities as industrial waste and washed-out fertilizer. Algae take up the heavy metals in their leaves and accumulate them. As a result, the heavy metals are absorbed indirectly by the snails as food, which then also accumulate them in their bodies. If one wants to investigate how high the exposure to heavy metals is in a certain area, the concentration of metals can be determined, for example, from the tissues of Phorcus turbinatus using optical atomic emission spectrometry (ICP-AES). The data thus acquired will help to estimate the future impact of the concentration of heavy metals on the Mediterranean Sea.

The influence of heavy metals on Phorcus turbinatus and their vital functions was examined, for example, with copper and chromium individually and in combination. When the snail was exposed to copper in several different concentrations, a reduced respiration rate was measured compared to the control group in natural seawater. The respiration rate is an important indicator of the metabolism and general well-being of the animals. The accumulation of copper in the tissue increased the longer the snail was exposed to the copper. Interestingly, the dice turban snail accumulates more copper when exposed to copper than when exposed to the same concentration of copper mixed with chromium. This indicates competition between the two metals. Since a changed respiration rate could be observed even with very low copper concentrations, even a low level of pollution has an impact on the animals.

Web links

Commons : Urban Dice Snail ( Phorcus turbinatus ) - Collection of images, videos and audio files

Individual evidence

↑ Kirsten M. Donald, Joanne Preston, Suzanne T. Williams, David G. Reid, David Winter: Phylogenetic relationships elucidate colonization patterns in the intertidal grazers Osilinus Philippi, 1847 and Phorcus Risso, 1826 (Gastropoda: Trochidae) in the northeastern Atlantic Ocean and Mediterranean Sea . In: Molecular Phylogenetics and Evolution . tape 62 , no. 1 , 2012, p. 35-45 .
↑ ^a ^b Rupert Riedl: Fauna and flora of the Mediterranean. A systematic marine guide for biologists and nature lovers. In: International review of the entire hydrobiology and hydrography . tape 70 , no. 3 , 1985, ISSN 0020-9309 , pp. 442–442 (3rd edition - with 3610 illustrations, 836 pp. Hamburg and Berlin: Verlag Paul Parey 1983. ISBN 3-490-23418-9 .).
↑ ^a ^b ^c Robert Menzies, Yael Cohen, Batia Lavie, Eviatar Nevo: Niche adaptation in two marine gastropods, Monodonta turbiformisandM. turbinata . In: Bolletino di zoologia . tape 59 , no. 3 , 1992, ISSN 0373-4137 , pp. 297-302 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h I. O. Alyakrinskaya: Some adaptations of Monodonta turbinata (Born, 1780) (Gastropoda, Prosobranchia, Trochidae) to feeding and habitation in the littoral zone . In: Biology Bulletin . tape 37 , no. 1 , 2010, ISSN 1062-3590 , p. 63-68 .
↑ G. Schifano, P. Censi: Oxygen isotope composition and rate of growth of patella coerulea, monodonta turbinata and M. articulata shells from the western coast of sicily . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 42 , no. 3-4 , 1983, ISSN 0031-0182 , pp. 305-311 .
↑ IO Alyakrinskaya: Adaptations of Certain Mediterranean Mollusks to Living in the Littoral Zone . In: Biology Bulletin . tape 31 , no. 4 , 2004, ISSN 1062-3590 , p. 406-415 .
↑ Guido Chelazzi, Stefano Focardi: A laboratory study on the short-term zonal oscillations of the trochid Monodonta turbinata (Born) (Mollusca: Gastropoda) . In: Journal of Experimental Marine Biology and Ecology . tape 65 , no. 3 , 1982, ISSN 0022-0981 , pp. 263-273 .
^ Carole C. Baldwin: FAO SPECIES IDENTIFICATION GUIDE FOR FISHERY PURPOSES. THE LIVING MARINE RESOURCES OF THE WESTERN CENTRAL PACIFIC . In: Copeia . tape 2003 , no. 1 , 2003, ISSN 0045-8511 , p. 212-214 .
↑ ^a ^b Onder Duysak: CEPHALOPOD DISTRIBUTION IN ISKENDERUN BAY (EASTERN MEDITERRANEAN-TURKEY) . In: Journal of Fisheries Sciences.com . 2008, ISSN 1307-234X .
↑ Artemis Nicolaidou, James A Nott: Metals in sediment, seagrass and gastropods near a nickel smelter in Greece: Possible interactions . In: Marine Pollution Bulletin . tape 36 , no. 5 , May 1998, pp. 360-365 .
↑ VA Catsiki, C. Vakalopoulou, M. Moraitou-Apostolopoulou, G. Verriopoulos: Monodonta turbinata (Born); toxicity and bio accumulation of Cu and Cu + Cr mixtures . In: Toxicological & Environmental Chemistry . tape 37 , no. 3-4 , 1993, ISSN 0277-2248 , pp. 173-184 .

[1] Kirsten M. Donald, Joanne Preston, Suzanne T. Williams, David G. Reid, David Winter: Phylogenetic relationships elucidate colonization patterns in the intertidal grazers Osilinus Philippi, 1847 and Phorcus Risso, 1826 (Gastropoda: Trochidae) in the northeastern Atlantic Ocean and Mediterranean Sea . In: Molecular Phylogenetics and Evolution . tape 62 , no. 1 , 2012, p. 35-45 .

[:0-2] Rupert Riedl: Fauna and flora of the Mediterranean. A systematic marine guide for biologists and nature lovers. In: International review of the entire hydrobiology and hydrography . tape 70 , no. 3 , 1985, ISSN 0020-9309 , pp. 442–442 (3rd edition - with 3610 illustrations, 836 pp. Hamburg and Berlin: Verlag Paul Parey 1983. ISBN 3-490-23418-9 .).

[:1-3] Robert Menzies, Yael Cohen, Batia Lavie, Eviatar Nevo: Niche adaptation in two marine gastropods, Monodonta turbiformisandM. turbinata . In: Bolletino di zoologia . tape 59 , no. 3 , 1992, ISSN 0373-4137 , pp. 297-302 .

[:2-4] ↑ ^a ^b ^c ^d ^e ^f ^g ^h I. O. Alyakrinskaya: Some adaptations of Monodonta turbinata (Born, 1780) (Gastropoda, Prosobranchia, Trochidae) to feeding and habitation in the littoral zone . In: Biology Bulletin . tape 37 , no. 1 , 2010, ISSN 1062-3590 , p. 63-68 .

[5] G. Schifano, P. Censi: Oxygen isotope composition and rate of growth of patella coerulea, monodonta turbinata and M. articulata shells from the western coast of sicily . In: Palaeogeography, Palaeoclimatology, Palaeoecology . tape 42 , no. 3-4 , 1983, ISSN 0031-0182 , pp. 305-311 .

[6] IO Alyakrinskaya: Adaptations of Certain Mediterranean Mollusks to Living in the Littoral Zone . In: Biology Bulletin . tape 31 , no. 4 , 2004, ISSN 1062-3590 , p. 406-415 .

[7] Guido Chelazzi, Stefano Focardi: A laboratory study on the short-term zonal oscillations of the trochid Monodonta turbinata (Born) (Mollusca: Gastropoda) . In: Journal of Experimental Marine Biology and Ecology . tape 65 , no. 3 , 1982, ISSN 0022-0981 , pp. 263-273 .

[8] Carole C. Baldwin: FAO SPECIES IDENTIFICATION GUIDE FOR FISHERY PURPOSES. THE LIVING MARINE RESOURCES OF THE WESTERN CENTRAL PACIFIC . In: Copeia . tape 2003 , no. 1 , 2003, ISSN 0045-8511 , p. 212-214 .

[:3-9] Onder Duysak: CEPHALOPOD DISTRIBUTION IN ISKENDERUN BAY (EASTERN MEDITERRANEAN-TURKEY) . In: Journal of Fisheries Sciences.com . 2008, ISSN 1307-234X .

[10] Artemis Nicolaidou, James A Nott: Metals in sediment, seagrass and gastropods near a nickel smelter in Greece: Possible interactions . In: Marine Pollution Bulletin . tape 36 , no. 5 , May 1998, pp. 360-365 .

[11] VA Catsiki, C. Vakalopoulou, M. Moraitou-Apostolopoulou, G. Verriopoulos: Monodonta turbinata (Born); toxicity and bio accumulation of Cu and Cu + Cr mixtures . In: Toxicological & Environmental Chemistry . tape 37 , no. 3-4 , 1993, ISSN 0277-2248 , pp. 173-184 .