Praunus flexuosus
| Praunus flexuosus | |
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| Species: | P. flexuosus
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| Binomial name | |
| Praunus flexuosus (O. F. Müller, 1776)
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Praunus flexuosus, known as the chameleon shrimp, is a species of opossum shrimp found in European waters. It reaches 26 mm (1.0 in) long, with a distinctly bent body, and closely resembles Praunus neglectus. It lives in shallow water and tolerates a wide range of salinities. It is found from northern France to the Baltic Sea, and was introduced to North America in the mid 20th century.
Description
[edit]Praunus flexuosus is a long, slender animal, with a pronounced bend in the abdomen.[1] It reaches sexual maturity at a length of around 18 millimetres (0.71 in), but can go on to attain a length of 26 mm (1.0 in).[1] Its colouration is highly variable, ranging from brown or red to green, which accounts for its common name of "chamaeleon shrimp".[2]
Praunus flexuosus is very similar to the related species P. neglectus. The two can be differentiated by the following characters:[1]
| Character | P. flexuosus | P. neglectus |
|---|---|---|
| Body length | 25–26 mm (1.0 in) | 20 mm (0.8 in) |
| Colour | black to colourless | usually grass green |
| Setae on antennal scale and uropods | colourless | violet or reddish purple |
| Antennal scale length | >3× peduncle | <3× peduncle |
| Antennal scale shape | 7–8× as long as broad | 5× as long as broad |
| Apex of antennal scale | shorter than spine terminating outer margin | longer than spine terminating outer margin |
| Tarsus of thoracic limbs 3–7 | 6 segmented | 5 segmented |
| Tarsus of thoracic limb 8 | 5 segmented | 4 segmented |
| Lateral margins of telson | 21–27 small spines | 18–20 larger spines |
| Cleft in telson | widely open, 1⁄6 of telson length | proximally narrow, 1⁄5 of telson length |
Taxonomy
[edit]Praunus flexuosus was the first mysidacean species ever to be formally described, when Otto Friedrich Müller described it under the name Cancer flexuosa in 1776.[3]
Distribution and ecology
[edit]Praunus flexuosus lives along the coast of the north Atlantic Ocean between 40° north and 71° north, and in the Baltic Sea.[1] There is only one doubtful record from further south than Roscoff.[1] It is "the only documented non-native marine zooplankton species established on the East Coast [of North America]".[4] It was first discovered in North America in 1960, on the north side of Cape Cod,[5] and has since colonised as far north as Nova Scotia.[6] This colonisation may have occurred after P. flexuosus was transported as a fouling animal on ships' hulls during the Second World War.[7] It was only discovered around the coast of Iceland in 1970, but has since proved to be common along Iceland's south-west coast.[7] This introduction may also have been facilitated by wartime convoys (see Battle of the Atlantic).[7]
P. flexuosus can tolerate salinities of 2‰–33‰.[8] It is often found on algae, and is most closely associated with the seaweed Fucus vesiculosus.[9] It lives in shallow water, and is often found around artificial constructions, such as docks.[10] It is an omnivore, feeding on debris and preying on small crustaceans, especially harpacticoid copepods,[11] but consumes a greater proportion of macrozooplankton than other common littoral mysids, such as Neomysis integer and Praunus inermis.[12] P. fleuosus is less gregarious than species such as N. integer.[9] When it detects a predator nearby, using a combination of visual and chemical cues, P. flexuosus hides among vegetation.[9]
Life cycle
[edit]Praunus flexuosus has two generations per year. A population overwinters, and produces a spring generation that appears in May or June, before dying off in the summer.[11] Some of the spring generation reach sexual maturity and reproduce in the autumn, producing the generation which will reproduce the following spring.[11] Females release eggs into a brood pouch or marsupium, where they are held until they hatch.[11]
References
[edit]- ^ a b c d e Mario de Kluijver; Sarita Ingalsuo (eds.). "Praunus flexuosus". Macrobenthos of the North Sea – Crustacea. Retrieved July 20, 2011.
- ^ Nellie Barbara Eales (1967). Littoral Fauna of the British Isles. Cambridge University Press. ISBN 978-0-521-04862-0.
- ^ Karl J. Wittmann (1999). "Global biodiversity in Mysidacea, with notes on the effects of human impact". In Frederick R. Schram & J. C. von Vaupel Klein (ed.). Crustaceans and the Biodiversity Crisis: Proceedings of the Fourth International Crustacean Congress, Amsterdam, the Netherlands, July 20–24, 1998. Crustacean Issues. Vol. 12. Brill. pp. 511–525. ISBN 978-90-04-11387-9.
- ^ Gregory Ruiz; Paul Fofonoff; Brian Steves; Alisha Dalhstrom (2011). "Marine crustacean invasions in North America: a synthesis of historical records and documented impacts". In Bella S. Galil; Paul F. Clark; James T. Carlton (eds.). In the Wrong Place – Alien Marine Crustaceans: Distribution, Biology and Impacts. Invading Nature. Vol. 6. Springer. pp. 215–250. ISBN 978-94-007-0590-6.
- ^ Roland L. Wigley (1963). "Occurrence of Praunus flexuosus (O. F. Müller) (Mysidacea) in New England waters". Crustaceana. 6 (2): 158. doi:10.1163/156854063X00534.
- ^ Kenneth L. Gosner (1999). "Mysid shrimps". A Field Guide to the Atlantic Seashore: From the Bay of Fundy to Cape Hatteras. Peterson Field Guide. Vol. 24. Houghton Mifflin Harcourt. pp. 229–230. ISBN 978-0-618-00209-2.
- ^ a b c Olafur S. Astthorsson (1987). "Records and life history of Praunus flexuosus (Crustacea: Mysidacea) in Icelandic waters". Journal of Plankton Research. 9 (5): 955–964. doi:10.1093/plankt/9.5.955.
- ^ D. S. McClusky & V. E. J. Heard (1971). "Some effects of salinity on the mysid Praunus flexuosus". Journal of the Marine Biological Association of the United Kingdom. 51 (3): 709–715. doi:10.1017/S0025315400015083.
- ^ a b c E. Lindén; M. Lehtiniemi & M. Viitasalo (2003). "Predator avoidance behaviour of Baltic littoral mysids Neomysis integer and Praunus flexuosus" (PDF). Marine Biology. 143: 845–850. doi:10.1007/s00227-003-1149-x.
- ^ P. J. Hayward; M. J. Isaac; P. Makings; J. Moyse; E. Naylor; G. Smaldon (1995). "Crustaceans". In P. J. Hayward & John Stanley Ryland (ed.). Handbook of the Marine Fauna of North-west Europe. Oxford University Press. pp. 289–461. ISBN 978-0-19-854055-7.
- ^ a b c d J. Mauchline (1971). "The biology of Praunus flexuosus and P. neglectus [Crustacea, Mysidacea]". Journal of the Marine Biological Association of the United Kingdom. 51 (3): 641–652. doi:10.1017/S0025315400015010.
- ^ Maiju Lehtiniemi & Hanna Nordström (2008). "Feeding differences among common littoral mysids, Neomysis integer, Praunus flexuosus and P. inermis". Hydrobiologia. 614 (1): 309–320. doi:10.1007/s10750-008-9515-9.