Freshwater prawns

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Freshwater prawns
Yamatonuma shrimp (Caridina multidentata)

Yamatonuma shrimp ( Caridina multidentata )

Systematics
Class : Higher crabs (Malacostraca)
Order : Decapods (decapoda)
Subordination : Pleocyemata
Partial order : Caridea
Superfamily : Atyoidea
Family : Freshwater prawns
Scientific name of the  superfamily
Atyoidea
de Haan , 1849
Scientific name of the  family
Atyidae
de Haan , 1849

The freshwater shrimp (Atyidae) are a family of decapods (Decapoda) with a shrimp-like habit. It comprises 469 species (as of 2011, since then a number of species have been newly described), almost all of which live in freshwater. The family also includes a number of genera that are adapted to brackish water, these live for example in pools of splash water in the intertidal zone or in caves that are separated from the sea but under the influence of sea water (so-called anchialine ). However, there are no actual marine species (living in the sea). With 433 freshwater species, the family is the most species-rich family of freshwater shrimp; However, the family Palaemonidae also come here , especially with the species-rich genus Macrobrachium , with around 300 species, four small, species-poor families and five representatives of the predominantly marine Alpheidae , so that not every shrimp living in freshwater belongs to this family. The German name “freshwater shrimp” should therefore be used with caution.

features

These are small to medium-sized crabs, large species, e.g. from the genus Atya, reach a body length of 12 centimeters. Most species are only about one to two centimeters long and often transparent or translucent. Your carapace almost always has a long and toothed, immobile rostrum in front, in some genera it is rudimentary or degenerate. The mandible never has a palpus. The stalked complex eyes can also be absent in species that live in underground waters. The first antennae always carry two flagella, without secondary flagella. Of the six pairs of striding legs (peraeopods) of the trunk section, the first two carry scissors ( chela ), the rear have claws that are often incised in a comb. Although the leg length usually increases towards the back, the last three pairs of legs are never noticeably elongated. Their carpus is regularly significantly shorter than the propodus. The shape of the claws of the first two peraeopods is characteristic of the family. These are relatively small and roughly the same size as one another. At the tip of both links they have a tuft of bristles that, when at rest, is reminiscent of a paintbrush . When the scissors are opened, the bristles are spread apart and form a fan-shaped structure with which the animals sweep up food from the surface or filter it out of the water . A similar brush is also found in Xiphocaris , the only genus of the Xiphocarididae family. The exopodite (the outer branch of the split leg) of the peraeopod is partially or completely reduced in many genera, often only the first two or three pairs of legs have an exopodite. In addition, the first three pairs of legs usually have a striped epipodite.

The life cycle of the Atyidae includes one of two types for most species: Many species have large, yolk-rich eggs from which bottom-living young animals hatch. This group includes most of the freshwater species. A second group has very small eggs from which planktonic living Zoea hatch larvae. In these, the larvae often develop in brackish water , even if the adult crabs live in fresh water, a special life cycle known as amphidromy .

Biology and ecology

Species of the Atyidae family occur in a large number of different bodies of water. Many species live in still waters such as lakes, others are adapted to running waters , including a number of species in fast-flowing mountain streams, even from waterfalls a specialized species is specified. Many species are groundwater animals in the karst or adapted to cave waters (stygobiont or troglobiont), for example the European genera Troglocaris and Gallocaris , the Indonesian Marosina or the Australian Stygiocaris and Pycnisia . Others have populations in both cave and surface waters (troglophilic species).

Most freshwater prawns eat detritus which they catch from the open water with the fans on their claws or pick it up from the ground and from aquatic plants. The biologist Geoffrey Fryer has studied the food intake of a number of sympatric Caribbean species in detail. Species such as Atya innocous move standing or, more often, slowly striding forward all four claws in front of them over the substrate. When the scissors come into contact with the ground, they are opened, opening the bristle compartment. It is then pulled over the stone surface and folded back in at the end of the path of the fan. The fan consists of coarser, tooth-shaped bristles that scrape the periphyton from the surface or stir up fine plant detritus (especially crushed fallen leaves), and fine filter bristles behind it that catch the material. The fan-closed scissors are brought to the mouth where the mouthparts and maxillipedes pick up the material. In addition, the animals are able to passively filter by holding the bristle fan in the water flow and collecting floating material.

distribution

The family is spread around the world. It is noticeable that isolated, oceanic islands of volcanic origin (i.e. without an old connection to the mainland) like Hawaii have their own freshwater species. In some cases, such as in the case of Caribbean species, it could be made probable that species are moved between different islands by the amphidromic zoea larvae (in these species the larvae descend in flowing waters into the estuary and live in brackish or seawater, the young crabs climb back in Freshwater habitats on) can be exchanged. It is most species-rich in the tropics, but some species penetrate into cool, temperate latitudes. Their center of diversity is in tropical East Asia. The ancient lakes of Sulawesi , the Philippines and southern China are particularly rich in species . Other centers are the island of Madagascar and Lake Tanganyika in Africa (with the genera Limnocaridina and Caridella ). Europe is poorly populated, most of the European species are cave-dwelling (trogobionte) species, such as the genus Troglocaris , in the karst areas of the Balkans.

In Germany the species Atyaephyra desmarestii occurs. Coming from the Mediterranean countries , it first made its home in the Rhine basin in the 19th century and then spread to eastern Germany and Austria. The three centimeters long, living in stagnant, weedy waters animal is because of its clarity and transparency are difficult to see.

Systematics and evolution

The family is generally considered to be of great geological age. It comes at least from the Cretaceous (from which the oldest fossil species are available), but possibly already from the ancient times. Even the oldest fossil finds come from freshwater sediments. According to genetic and morphological data, its sister group is the small family Xiphocarididae , which was previously included in the Atyidae. Otherwise your position within the Caridea sub-order is not secured. The phylogeny of the Atyidae was investigated by a phylogenomic study in 2012 . Accordingly, the family falls into three clades . None of them correspond to any of the subfamilies suggested for the family by the Dutch biologist Lipke Bijdeley Holthuis . The subfamilies had been questioned before, they were no longer used in the 2011 species catalog. The family is therefore currently no longer divided into subfamilies. When examined, the North American genus Syncaris, which lives in California waters, was found to be the most basal line. A second clade includes the earlier subfamily Paratyinae together with some genera from other subfamilies, the third the genera of the earlier subfamilies Atyinae and most of the Caridellinae, these could not be distinguished from each other. The species-richest genus Caridina turned out to be polyphyletic, i.e. H. it is an artificially delimited grouping. Accordingly, there are no longer any genera that are common worldwide. The origin of the family is believed to be in East Asia, the Atlantic area was colonized in three independent waves, with the fauna east and west of the Atlantic corresponding.

The following genera occur in Europe:

  • Atyaephyra
  • Dugastella a species ( Dugastella valentina ) with an isolated, island-like occurrence in Valencia, Spain (a second species in Morocco)
  • Gallocaris monotypic genus, the only species Gallocaris inermis , in caves and karst waters of southern France
  • Troglocaris in cave and karst waters of the Balkans. Species number unclear due to numerous crypto-species.
  • Typhlatya two species in the southwestern Mediterranean region (Spain and France)

other selected genera:

Atyids in the aquarium hobby

In recent years the keeping of shrimp in freshwater aquariums has increased significantly. This is partly due to the Japanese aquarist and photographer Takashi Amano , who with his books popularized the keeping of shrimps from the genus Caridina . In particular, he cultivated the Yamatonuma shrimp ( Caridina multidentata ) to combat algae, which is why it is often sold as "Amano" or "Algae shrimp". Other Atyidae, which are available in specialist shops, belong to the genus of the fan shrimp ( Atyopsis ). The glass shrimp ( Macrobrachium ) do not belong to the Atyidae . Although they also live in fresh water, they belong to the family of rock and partner shrimp (Palaemonidae).

Numerous types and shapes are now available. The dwarf shrimp in particular are enjoying increasing popularity. Here is an excerpt of known species: Crystal Red Shrimp , Black Tiger Shrimp , Blue tiger shrimp, caridina multidentata , Red Fire Shrimp , Weißperlengarnele (White Pearl), Blue Pearl, Green Shrimp .

Danger

According to a current global assessment of the endangerment of all freshwater shrimp species, more than a third of the species (37 percent) of the Atyidae family are threatened with extinction. The number of threatened species could be even higher because insufficient data is available on many species (data deficient). The most important sources of danger are water pollution and threats from introduced invasive species, many are also threatened by interventions in hydrology, for example through dam construction and mining. Seven species are threatened by excessive foraging in wild stocks for the aquarium trade. At least four species are most likely already extinct, three from China and one from the Caribbean.

literature

  • Hans-Eckhard Gruner: Class Crustacea. In: HE Gruner, M. Moritz, W. Dunger (editor): Textbook of special zoology (founded by Alfred Kaestner). Volume I: Invertebrates, Part 4 Arthropoda (without Insecta). 4th edition 1993. Gustav Fischer Verlag, Jena. ISBN 3-334-60404-7 . (Page 984)
  • LB Holthuis: The recent genera of the Caridean and Stenopodidean shrimps (Class Crustacea, Order Decapoda, Supersection Natantia) with keys for their determination. Zoologische Verhandelingen Leiden 26, 1955. 157 pages

Individual evidence

  1. ^ A b S. De Grave & CHJM Fransen (2011): Carideorum Catalogus: The Recent Species of the Dendrobranchiate, Stenopodidean, Procarididean and Caridean Shrimps (Crustacea: Decapoda). Zoological Mededelingen Leiden 85 (9): 195-589.
  2. ↑ a b c Sammy De Grave, Kevin G. Smith, Nils A. Adeler, Dave J. Allen, Fernando Alvarez, Arthur Anker, Yixiong Cai, Savrina F. Carrizo, Werner Klotz, Fernando L. Mantelatto, Timothy J. Page, Jhy-Yun Shy, José Luis Villalobos, Daisy Wowor (2015): Dead Shrimp Blues: A Global Assessment of Extinction Risk in Freshwater Shrimps (Crustacea: Decapoda: Caridea). PLoS ONE 10 (3): e0120198. doi : 10.1371 / journal.pone.0120198
  3. ↑ a b Kristina von Rintelen, Timothy J. Page, Yixiong Cai, Kevin Roe, Björn Stelbrink, Bernard R. Kuhajda, Thomas M. Iliffe, Jane Hughes, Thomas von Rintelen (2011): Drawn to the dark side: A molecular phylogeny of freshwater shrimps (Crustacea: Decapoda: Caridea: Atyidae) reveals frequent cave invasions and challenges current taxonomic hypotheses. Molecular Phylogenetics and Evolution 63: 82-96. doi : 10.1016 / j.ympev.2011.12.015
  4. ^ Raymond T. Bauer (2013): Amphidromy in shrimps: a life cycle between rivers and the sea. Latin American Journal of Aquatic Research 41 (4): 633-650. doi : 10.3856 / vol41-issue4-fulltext-2
  5. ↑ G. Fryer (1977): Studies on the Functional Morphology and Ecology of the Atyid Prawns of Dominica. Philosophical Transactions of the Royal Society of London. Series B, BiologicalSciences 277, No. 952: 57-129. JSTOR 2417643
  6. ↑ Timothy J. Page, Benjamin D. Cook, Thomas von Rintelen, Kristina von Rintelen, Jane M. Hughes (2008): Evolutionary relationships of atyid shrimps imply both ancient Caribbean radiations and common marine dispersals. Journal of the North American Benthological Society 27 (1): 68-83. doi : 10.1899 / 07-044R.1
  7. ^ S. De Grave, Y. Cai, A. Anker (2008): Global diversity of shrimps (Crustacea: Decapoda: Caridea) in freshwater. Hydrobiologia 595: 287-293. doi : 10.1007 / s10750-007-9024-2
  8. ↑ Heather D. Bracken, Sammy de Grave, Darryl L. Felder (2009): Phylogeny of the Infraorder Caridea Based on Mitochondrial and Nuclear Genes (Crustacea: Decapoda). In: Joel W. Martin, Keith A. Crandall, Darryl L. Felder (editors): Decapod Crustacean Phylogenetics. CRC Press, 2009: 281-305. ISBN 978-1-4200-9258-5 . doi : 10.1201 / 9781420092592-c14
  9. ↑ Boris Sket & Valerija Skakšek (2008): European cave shrimp species (Decapoda: Caridea: Atyidae), redefined after a phylogenetic study; redefinition of some taxa, a new genus and four new Troglocaris species. Zoological Journal of the Linnean Society 155: 786-818.
  10. ↑ Alejandro Botello, Thomas M. Iliffe, Fernando Alvarez, Carlos Juan, Joan Pons, Damià Jaume (2013): Historical biogeography and phylogeny of Typhlatya cave shrimp (Decapoda: Atyidae) based on mitochondrial and nuclear data. Journal of Biogeography 40: 594-607. doi : 10.1111 / jbi.12020
  11. ^ Damià Jaume & Franck Bréhier (2005): A new species of Typhlatya (Crustacea: Decapoda: Atyidae) from anchialine caves on the French Mediterranean coast. Zoological Journal of the Linnean Society 144: 387-414.

Web links

Commons : Freshwater Shrimp (Atyidae)  - Collection of pictures, videos and audio files
Wikibooks: Keeping Freshwater Shrimp  - A Wikibook for keeping freshwater shrimp in an aquarium