Club polyp

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Club polyp
Cordylophora caspia, portion of a female colony (from Allman, 1872) .png

Club polyp ( Cordylophora caspia )

Systematics
Subclass : Leptolinae
Order : Anthomedusae
Subordination : Filifera
Family : Oceaniidae
Genre : Cordylophora
Type : Club polyp
Scientific name
Cordylophora caspia
( Pallas , 1771)

The club polyp ( Cordylophora caspia , syn .: C. lacustris Allman) is also called monkey hair and is a colony-forming brackish-water polyp that was distributed worldwide as a neozoon from the Caspian Sea . The polyp lives predatory and mostly colonizes hard substrate.

features

Cordylophora caspia forms colonies consisting of polyps that sit on hard substrates at the bottom of the water. Colonies consist of root-like creeping tubes called stolons, which are enclosed by a brown, stable shell called perisarc. From these rise yellowish-colored, upright, tuft-like branched polyps, which can usually reach a height of about three, a maximum of about 10 centimeters. Each stick branches into about 40 polyp stalks (hydranthophores), the branching pattern can be uniform, depending on the environmental conditions, or an elongated main axis with short side branches is created. The white to pale pink colored single polyps sit at the end of the polyp stalks, they are not covered by the perisarc. Single polyps (hydrant, because of their similarity to hydra ) are club- or spindle-shaped in outline, they can contract in the event of disturbances. They reach about 1 to 2 millimeters in length. In the end, they have a structure called a hypostome that supports the mouth opening. In Cordylophora, the tentacles are neither ring-shaped around the mouth opening nor concentrated in ribbon-like zones (as in pachycordyls ), but rather scattered around the body of the polyp. Each polyp carries 14 to 16 (maximum up to 27) tentacles that reach about 1.4 millimeters in length. The sexual individuals called gonophores arise on the lateral shoots of the polyp stalk, which like the single polyps (hydrant) are zooids , i.e. individuals within the common colony. The gonophores are elliptical in shape and enclosed by the perisarc. The mature sex cells (gametes) are released through a central opening. Cordylophora is separate from the sexes, so there are male and female individuals.

Mature, mated gametes form a planular larva that swims around until it has found a suitable habitat. Here she settles down and founds a new colony. Alternatively, colonies can also reproduce vegetatively asexually. A medusa stage is absent in the species.

Ecology and way of life

Specimen in the Museum of Natural History, Berlin

Cordylophora caspia is a type of brackish water , but can also live in pure fresh water , in which case waters with relatively high ion contents are preferred. There is evidence that the ecotypes living in freshwater and brackish water are genetically different and may develop cryptic species . The species is not fussy about water temperature and occurs from subtropical and temperate to boreal waters.

As a hard substrate colonist, Cordylophora can grow up on the hulls of ships ( called fouling ) and is thus easily carried off into new waters and habitats.

Problems

The species was and is distributed almost worldwide, mainly through shipping and canal construction. In Europe it has been widespread since the middle of the 20th century in almost all estuaries of the rivers that flow into the sea, in large rivers also far inland. The species immigrated into the coastal waters of the Baltic Sea, probably via the newly built canals (first evidence: 1870). It was first registered in the estuary of the Elbe, which flows into the North Sea, in 1858. The species continues to spread. So in 2001 the Balaton in Hungary was reached. In North America (Massachusetts) the first record was in 1860, today the species is particularly problematic in the Great Lakes area .

The occurrence of monkey hair, because of its long "fibers", represents a considerable problem in the provision of cooling water for heat exchangers and condensers , since the pipes of such apparatuses clog very quickly without an upstream filter . From a procedural point of view, pollution by monkey hair belongs to macrofouling .

Phylogeny and Taxonomy

The species was first described as Tubularia caspia in 1771 by the naturalist Peter Simon Pallas . The Cordylophora lacustris described by Allman in 1844 , the type species of the genus Cordylophora , is considered synonymous with it. Due to the high morphological plasticity, the wide spread into new habitats and certain differences between fresh and brackish water forms, the differentiation of the species is difficult. At times up to eight species were distinguished within the genus, but many reviewers consider Cordylophora caspia to be the only species.

The species is assigned to the family Oceaniidae (sometimes written Oceanidae), the name Cordylophoridae is, according to popular opinion, synonymous with it, about which there are differing views (there are also different views regarding the validity of these names). They belong to a morphologically well delimitable group of hydrozoa called Filifera . The delimitation of families according to morphological characteristics is difficult. According to genetic data, Cordylophora is closely related to the Pachycordyle genus, which also lives in freshwater . The families are probably not monophyletic units.

Individual evidence

  1. ↑ Peter Schuchert (2004): Revision of the European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Families Oceanidae and Pachycordylidae. Revue Suisse de Zoologie 111 (2): 315-369.
  2. ↑ P. Schuchert (2019): World Hydrozoa Database. Cordylophora caspia (Pallas, 1771). Accessed through WoRMS World Register of Marine Species , accessed July 2, 2019
  3. ↑ Nadine C. Folino-Rorem, John A. Darling, Cori A. D'Ausilio (2009): Genetic analysis reveals multiple cryptic invasive species of the hydrozoan genus Cordylophora. Biological Invasions 11: 1869-1882. doi: 10.1007 / s10530-008-9365-4
  4. ^ Dagmar Lackschewitz, Karsten Reise, Christian Buschbaum, Rolf Karez: Neobiota in German coastal waters. Introduced and cryptogenic animal and plant species on the German North and Baltic Sea coasts. published by the State Office for Agriculture, Environment and Rural Areas of Schleswig-Holstein in 2014. ISBN 978-3-937937-73-1
  5. ↑ IB Muskó, Melinda Bence, Csilla Balogh (2008): Occurrence of a new Ponto-Caspian invasive species, Cordylophora caspia (Pallas, 1771) (Hydrozoa: Clavidae) in Lake Balaton (Hungary). Acta zoologica Academiae Scientiarum Hungaricae 54 (2): 169-179.
  6. ↑ Thomas Jankowski, Allen G. Collins, Richard Campbell (2008): Global diversity of inland water cnidarians. Hydrobiologia 595: 35-40. doi: 10.1007 / S10750-007-9001-9
  7. ↑ María A. Mendoza ‐ Becerril, Adrian José Jaimes ‐ Becerra, Allen G. Collins, Antonio C. Marques (2018): Phylogeny and morphological evolution of the so ‐ called bougainvilliids (Hydrozoa, Hydroidolina). Zoologica Scripta 47 (5): 608-622. doi: 10.1111 / zsc.12291

literature

  • EA Arndt: The ecological niche of Cordylophora caspia (Pallas, 1771) . Limnologica 15 (2), 1984, pp. 469-477.
  • H. Franz, HJ Jatzek: The club polyp Corylophora caspi (Pallas 1771) in the river system of the Rhine. Mainzer Naturwissenschaftliches Archiv 23 (1985), pp. 109–118.
  • NC Folino: The freshwater expansion and classification of the colonial hydroid Cordylophora (Phylum Cnidaria, Class Hydrozoa). Marine bioinvasions . Proceedings of the First National Conference, Massachusetts Institute of Technology, USA (1999). Pp. 139-144.

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