Theodoxus fluviatilis
| Theodoxus fluviatilis | |
|---|---|
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| 1854 engraving of Theodoxus fluviatilis | |
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| Four shells of Theodoxus fluviatilis | |
| Conservation status | |
| NE[4] | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Neritimorpha clade Cycloneritimorpha |
| Superfamily: | Neritoidea |
| Family: | Neritidae |
| Subfamily: | Neritininae |
| Tribe: | Theodoxini |
| Genus: | Theodoxus |
| Subgenus: | Theodoxus[5] |
| Species: | T. fluviatilis |
| Binomial name | |
| Theodoxus fluviatilis (Linnaeus, 1758)[6] | |
| Synonyms[7][8][9][10] | |
| |
Theodoxus fluviatilis, common name the river nerite, is a species of small freshwater and brackish water snail with a gill and an operculum, an aquatic gastropod mollusk in the family Neritidae, the nerites.
Theodoxus fluviatilis is the type species of the genus Theodoxus.[10] Anistratenko (2005)[10] designated the lectotype for Theodoxus fluviatilis.[10]
Subspecies
Several subspecies are (inconsistently) recognized by various authors:
- Theodoxus fluviatilis fluviatilis (Linnaeus, 1789)[12][13][5] - it has been described from freshwater[14]
- Theodoxus fluviatilis fluviatilis f. fontinalis Brard, 1815[12] or as a synonym of Theodoxus fluviatilis[5]
- Theodoxus fluviatilis littoralis (Linnaeus, 1789)[12] - it has been described from brackish water,[14] or as a synonym of Theodoxus fluviatilis[5]
- Theodoxus fluviatilis sardous (Menke, 1830)[5]
- Theodoxus fluviatilis subthermalis Issel, 1865[5] - or Theodoxus subthermalis (Bourguignat in Issel, 1865)[7]
- Theodoxus fluviatilis thermalis (Dupuy, 1851)[5]
Theodoxus fluviatilis thermalis Syntype MHNT - Theodoxus fluviatilis transversetaeniatus A. J. Wagner, 1928[5]
- Theodoxus fluviatilis dalmaticus Sow. - in Lake Ohrid[15]
- Theodoxus fluviatilis euxinus (Clessin, 1885) has been considered as a subspecies[13] - see Theodoxus euxinus (Clessin, 1886)[5]
Bunje (2005)[9] does not consider Theodoxus velox Anistratenko, 1999[16] to be a distinct species from Theodoxus fluviatilis.[9]
Distribution
The distribution of this species is European.[17] Its distribution is scattered in Europe and in Western Asia[10] except the Alps and regions immediately north of the Alps.[8] It does not live in Norway.[8][14] Theodoxus fluviatilis has the most widespread distribution of all species in the genus Theodoxus.[9]
Western Europe:
- Ireland[18]
- Orkney,[14] Great Britain[18]
- Netherlands[19]
- France[18]
- Switzerland - critically endangered[8]
- Iberia[14]
Central Europe:
- Austria - non-indigenous, Danube near Tulln, Lower Austria, since 2001[20]
- Czech Republic - extinct in Bohemia.[21][22] The only findings were in the Elbe river near Litoměřice in 1917.[22] The most recent findings of empty shells were in 1943.[22]
- Germany[14] - high endangered (Stark gefährdet)[23]
- Poland[14]
- Slovakia - non-indigenous[24][22]
Northern Europe:
- Denmark[14]
- Sweden - up to 58° N[8]
- Åland Islands - known alive there since 1994[14][25] (belongs to Finland)
Eastern Europe:
- Estonia[14]
- Lithuania[14]
- Latvia[14]
- Belarus[26]
- western Russia[14]
- Gulf of Odessa - since 1997[27]
- Ukraine - non-indigenous, first record in 1955[28]
Southern Europe:
- Croatia[29]
- Lake Ohrid, Macedonia - subspecies Theodoxus fluviatilis dalmaticus[15]
- Albania[30] (cf. lake Ohrid is between Albania/Macedonia)
- mainland Greece and Crete[1][9]
Asia:
Bunje (2005)[9] hypothetized that the ancestral range of Theodoxus fluviatilis was the Ponto-Pannonian region (southern Ukraine, Romania and Hungary).[9] Firstly it colonized northern Italy, Greece and Turkey; in the second phase it colonized Spain, France and Germany.[9] Finally in the Holocene it colonized the British Isles, Sweden and the Baltic Sea.[9]
Shells of Theodoxus fluviatilis have also been found in the following sites:
- Upper Paleolithic archaeological site in the cave Caldeirão, Pedreira (Tomar), Tomar Municipality, Portugal.[31]
- about 6000 years B.P. in Litorina age on Åland Islands[25]
Description
Theodoxus fluviatilis was originally described (under the name Nerita fluviatilis) by Carl Linnaeus in 1758. Linnaeus's original text (the type description) was very short, and reads as follows:[6]
| “ |
Nerita fluviatilis, n. 632: testa rugosa, labiis edentilis. Habitat in Europa cataractis. |
” |
The shell is depressed, strongly calcified and with three whorls.[18][32] It is basically whitish or yellowish with dark reddish or violetish reticulate pattern, very variably arranged (adapted to environmental factors), sometimes partly in bands, occasionally evenly dark.[8] It is very variable in colors and in color patterns (it has great polymorphism in colors).[10] In the Mediterranean region there are slightly different forms.[8] The shell may be corroded.[14] Operculum is light reddish with red margin,[8] with broad rib and without apophysis.[8]
The width of the shell is 5-9 mm,[8] up to 11 mm[22] or up to 13 mm.[8] The height of the shell is 4-6.5 mm,[8] or up to 7 mm.[22]
The maximum width of the shell of freshwater population is 13.1 mm.[14] The maximum height of the shell of freshwater population is 9.3 mm.[14] The maximum weight of the shell is 343 mg.[14]
The maximum width of the shell of brackish water population is 9.3 mm.[14] The maximum height of the shell of brackish water population is 5.8 mm.[14] The maximum weight of the shell is 124 mg.[14]
The animal is light yellow with head black.[8] Tentacles are greyish and long.[8] Eyes are big and black, foot is whitish.[8]
 Drawing of the reproductive system of a male by Lehmann (1873)[3] shows testis (on the left), prostate, vas deferens and penis (on the right). |
 Drawing of the reproductive system as firstly described (correctly) by Gustave Gilson (1896)[2] of a female shows: 1 - ovarium 2 - oviduct 3 - uterus 4 - diverticulum 5 - connection between bursa copulatrix and uterus 6 - receptaculum seminis 7 - bursa copulatrix 8 - vagina. |
Ecology
This small snail inhabits the central and lower parts of rivers (up to 13 m deep),[8] also in brackish water[8] in tidal rivers of the estuary.[18] Sometimes it lives in lakes on unvegetated bottom.[18] It rarely lives in springs (rheocrenes), in ground water and in caves.[18] For example there was pH 7.8-8.9 in lakes in Åland Islands with Theodoxus fluviatilis.[25]
The ability of Theodoxus fluviatilis to live in freshwater and also in brackish water is a representation of phenotypic plasticity of this species.[9] It can live up to 60 m depth in coastal waters.[14] Brackish water populations can live in salinity up to 15 ‰ in the Baltic Sea[12][23] or up to 18 ‰ in the Baltic Sea and in the Black Sea.[9] Populations from brackish water tolerates higher salinity than populations from freshwater.[14] Brackish water populations have much higher accumulation of ninhydrin-positive substances in the foot.[33]
This species requires a stony substrate.[8] It lives on pebbles, sometimes on boulders and rarely on dead wood.[18] It tolerates mild organic pollution, low oxygen content (down to below 2 mg/liter) but does not tolerate long periods of droughts or ice.[8] It lives in mesotrophic waters, sometimes in oligotrophic.[18] Theodoxus fluviatilis has large phenotypic plasticity and it was found to be living on stones and on the dead wood in freshwater environment; while it lives on stones and on Fucus vesiculosus, Potamogeton spp. and Zostera marina in brackish water in the Baltic Sea.[14] It can also occur on aggregates of Mytilus.[14]Theodoxus fluviatilis together with the isopod Saduria entomon has been found to be a dominant part of the fauna biomass in the central and northern Baltic Sea.[34] Brackish water populations can reach densities up to 200-1000 snails per m².[14] Theodoxus fluviatilis dalmaticus in Lake Ohrid can reach population densities up to 6412 snails per m².[15]
It feeds on algae cover[8] and diatoms on stones.[14]
Sexes are separate (dioecious) and cross-fertilization occurs.[18] There is unique structure of the flagellum of spermatozoon: the flagellum is divided into two parts.[35] Eggs are laid in an egg mass[18] from mid-April to October.[8] There are less than 10 eggs.[18] Only one egg develops and other eggs serve as nutrition for the embryo.[36]
0.5-1 mm sized juveniles hatch after 30 days (in 25°C) or after 65 days (in 20°C).[12][8] Sexual maturity is in less than 1 year.[18] The life span is 2-3 years.[8]
Parasites of Theodoxus fluviatilis include:
- The trematode Plagioporus skrjabini - Theodoxus fluviatilis serves as the first intermediate host[37]
This species is threatened mainly by river engineering, and water pollution in densely populated regions.[8]
References
This article incorporates public domain text from references[6][8]
- ↑ 1.0 1.1 "Picture summary of Theodoxus-fluviatilis_04.jpg". AnimalBase, last modified 20 June 2008, accessed 13 April 2011.
- ↑ Gilson G. (1896) "The female organs of Neritina fluviatilis". Proceedings of the Malacological Society of London 2: 81-83.
- ↑ Lehmann R. (1873). Die lebenden Schnecken und Muscheln der Umgegend Stettins und in Pommern mit besonderer Berücksichtigung ihres anatomischen Baues. R. Friedländer & Sohn, Berlin. page 261. Plate 19, figure 94.
- ↑ 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Cited 14 June 2007.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 "Theodoxus (Theodoxus) fluviatilis". Fauna Europaea, last update 27 January 2011, accessed 12 April 2011.
- ↑ 6.0 6.1 6.2 Linnaeus C. (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. 10th edition. Vermes. Testacea: 700-781. Holmiae. (Salvius). page 777.
- ↑ 7.0 7.1 Kantor Yu I., Vinarski M. V., Schileyko A. A. & Sysoev A. V. (published online on March 2, 2010). "Catalogue of the continental mollusks of Russia and adjacent territories". Version 2.3.1.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 8.11 8.12 8.13 8.14 8.15 8.16 8.17 8.18 8.19 8.20 8.21 8.22 8.23 8.24 "Species summary for Theodoxus fluviatilis". AnimalBase, last modified 21 September 2009, accessed 11 April 2011.
- ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 Bunje, P. M. E. (2005). "Pan-European phylogeography of the aquatic snail Theodoxus fluviatilis (Gastropoda: Neritidae)". Molecular Ecology 14 (14): 4323–4340. doi:10.1111/j.1365-294X.2005.02703.x. PMID 16313596. PDF.
- ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 Anistratenko V. V. (2005). "Lectotypes for Tricolia pullus, Gibbula divaricata and Theodoxus fluviatilis (Mollusca, Gastropoda) revisited". Vestnik zoologii 39(6): 3-10. PDF .
- ↑ "Species in genus Theodoxus" (n=20). AnimalBase, accessed 11 April 2011.
- ↑ 12.0 12.1 12.2 12.3 12.4 Glöer P. (2002). Die Süßwassergastropoden Nord- und Mitteleuropas. Die Tierwelt Deutschlands, ConchBooks, Hackenheim, 326 pp., ISBN 3-925919-60-0.
- ↑ 13.0 13.1 13.2 Yildirim M. Z., Koca S. B. & Kebapçi U. (2006). "Supplement to the Prosobranchia (Mollusca: Gastropoda) Fauna of Fresh and Brackish Waters of Turkey". Turkish Journal of Zoology 30: 197-204. PDF
- ↑ 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 14.10 14.11 14.12 14.13 14.14 14.15 14.16 14.17 14.18 14.19 14.20 14.21 14.22 14.23 14.24 14.25 Zettler M. L., Frankowski J., Bochert R. & Röhner M. (2004). "Morphological and ecological features of Theodoxus fluviatilis(Linnaeus, 1758) from Baltic brackish water and German freshwater populations". Journal of Conchology 38(3): 305-316.PDF.
- ↑ 15.0 15.1 15.2 Smiljkov, S.; Budzakoska-Gjoreska, B.; Sapkarev, J.; Trajanovski, S. (2007). "Dominant species of the gastropod fauna from the littoral region in Lake Ohrid of R. Macedonia". Prilozi / Makedonska akademija na naukite i umetnostite, Oddelenie za bioloski i medicinski nauki = Contributions / Macedonian Academy of Sciences and Arts, Section of Biological and Medical Sciences 28 (1): 137–144. PMID 17921924.. PDF.
- ↑ Anistratenko O. Y., Starobogatov Y. I. & Anistratenko V. V. (1999). "Mollusks of the genus Theodoxus (Gastropoda, Pectinibranchia, Neritidae) from the Black and the Azov seas basin". Vestnik Zoologii 33: 11-19.
- ↑ (Slovak) Lisický M. J. (1991). Mollusca Slovenska [The Slovak molluscs]. VEDA vydavateľstvo Slovenskej akadémie vied, Bratislava, 344 pp.
- ↑ 18.0 18.1 18.2 18.3 18.4 18.5 18.6 18.7 18.8 18.9 18.10 18.11 18.12 Falkner G., Obrdlík P., Castella E. & Speight M. C. D. (2001). Shelled Gastropoda of Western Europe. München: Friedrich-Held-Gesellschaft, 267 pp.
- ↑ Theodoxus fluviatilis, accessed 25 September 2008
- ↑ (German) Schultz H. & Schultz O. (2001). "Erstnachweis der Gemeinen Kahnschnecke, Theodoxus fluviatilis (LINNAEUS, 1758) in Österreich (Gastropoda: Neritidae)". Annalen des Naturhistorischen Museums in Wien 103B: 231-241. PDF.
- ↑ Red List of the molluscs (Mollusca) of the Czech Republic
- ↑ 22.0 22.1 22.2 22.3 22.4 22.5 (Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca Suppl. 1: 1-37. PDF.
- ↑ 23.0 23.1 Glöer P. & Meier-Brook C. (2003). Süsswassermollusken. DJN, pp. 134, pages 29, 108, ISBN 3-923376-02-2.
- ↑ Čejka T. & Horsák M. (2002). "First records of Theodoxus fluviatilis and Sphaerium solidum (Mollusca) from Slovakia". Biologia, Bratislava 57(5): 561-562.
- ↑ 25.0 25.1 25.2 Carlsson R. (2000). "The distribution of te gastropods Theodoxus fluviatilis (L.) and Potamoyrgus antipodarum (Gray) in lakes on the Åland Islands, southwestern Finland". Boreal Environment Research 5: 187-195. PDF.
- ↑ Nagorskaya L., Moroz M., Laeno T., Veznovetz V., Pillot H. M., Dijkstra K. D. B. & Reemer M. (2002). "Macrofauna in floodplain pools and dead branches of the Pripyat river, Belarus". The Institute of Zoology NAS Belarus, 158 pp., page 56. PDF.
- ↑ (Russian) Butenko O. (Бутенко О. И.) (2001). "Моллюски рода Theodoxus (Gastropada, Neritidae) в Одесском заливе Черного моря. [Mollusks of Theodoxus genus (Gastropoda, Neritidae) in the Odessa Bay (the Black Sea)]". Ekologiya Morya 58: 27-28. PDF.
- ↑ Alexandrov B., Boltachev A., Kharchenko T., Lyashenko A., Son M., Tsarenko P. & Zhukinsky V. (2007). "Trends of aquatic alien species invasions in Ukraine". Aquatic Invasions 2(3): 215-242. PDF.
- ↑ Beran L. (2009). "The first record of Anisus vorticulus (Troschel, 1834) (Gastropoda: Planorbidae) in Croatia?". Malacologica Bohemoslovaca 8: 70. PDF.
- ↑ Fehér Z. & Eröss Z. P. (2009). "Checklist of the Albanian mollusc fauna". Schriften zur Malakozoologie 25 22-38. PDF.
- ↑ (Portuguese) Callapez P. (2003). "Moluscos marinhos e fluviais do Paleolítico superior da Gruta do Caldeirão (Tomar, Portugal): evidências de ordem sistemática, paleobiológica e paleobiogeográfica". Revista Portuguesa de Arqueologia 6(1): 5-15. PDF.
- ↑ Theodoxus fluviatilis. Marine Species Identification Portal, accessed 11 April 2011.
- ↑ Symanowski, F.; Hildebrandt, J. P. (2009). "Differences in osmotolerance in freshwater and brackish water populations of Theodoxus fluviatilis (Gastropoda: Neritidae) are associated with differential protein expression". Journal of Comparative Physiology B 180 (3): 337–346. doi:10.1007/s00360-009-0435-4. PMID 20012055.
- ↑ Kautsky H. (1989). "Quantitative distribution of plant and animal communities of the phytobenthic zone in the Baltic Sea". Askö Laboratory, Stockholm. .
- ↑ Giusti, F.; Selmi, M. G. (1982). "The morphological peculiarities of the typical spermatozoa of Theodoxus fluviatilis (L.) (Neritoidea) and their implications for motility". Journal of ultrastructure research 78 (2): 166–177. PMID 7086934.
- ↑ (Czech) Beran L. (1998). Vodní měkkýši ČR. Vlašim, 113 pp., ISBN 80-902469-4-X. page 45.
- ↑ (Russian) Chernogorenko, M. I.; Komarovova, T. I.; Kurandina, D. P. (1978). "Life cycle of the trematode, Plagioporus skrjabini Kowal, 1951 (Allocreadiata, Opecoelidae)". Parazitologiia (in Russian) 12 (6): 479–486. PMID 733319..
External links
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Wikimedia Commons has media related to Theodoxus fluviatilis. |
- Theodoxus fluviatilis at National Center for Biotechnology Information (NCBI)
- Bondesen P. (1940). "Preliminary investigations into the development of Neritina fluviatilis L. in brackish and fresh waters". Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening 104: 283-318.
- Boycott A. E. (1936). "Neritina fluviatilis in Orkney". Journal of Conchology 20: 199-200.
- Kangas, P.; Skoog, G. (1978). "Salinity tolerance of Theodoxus fluviatilis (Mollusca, Gastropoda) from freshwater and from different salinity regimes in the Baltic Sea". Estuarine and Coastal Marine Science 6 (4): 409. doi:10.1016/0302-3524(78)90131-7..
- Lumbye, J. R. (1958). "The oxygen consumption of Theodoxus fluviatilis (L.) and Potamopyrgus jenkinsi (Smith) in brakish and fresh water". Hydrobiologia 10: 245–262. doi:10.1007/BF00142190..
- Skoog G. (1971). "Variations in the distribution of Theodoxus fluviatilis on stony locations in the northern Baltic proper". Thalassia Jugoslavica 7: 363-372.
- (German) Weichtier des Jahres 2004. Mollusc of the year 2004 (in Germany).
- Örstan A. (2007). "New year, new snail: Theodoxus fluviatilis". Snail's tales. - with photos of eggs and view inside the shell with resorbed columella.
- Theodoxus fluviatilis Species account and photograph at Mollusc Ireland.
- 1862 drawing of Theodoxus fluviatilis