Copenhagen cockle
| Copenhagen cockle | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Parvicardium hauniense | ||||||||||||
| ( Høpner Petersen & Russell , 1971) |
The Copenhagen cockle ( Parvicardium hauniense ) is a shell - type from the family of cockles (Cardiidae) in order Cardiida . It is endemic to the western Baltic Sea .
features
The equally flared, moderately expanded housing is up to about 6 mm long. The vertebrae, which are curled forward, sit in front of the midline, which makes the housing slightly uneven. It is rounded to slightly rounded-egg-shaped in outline and slightly skewed due to the slight extension of the rear end. The posterior dorsal margin is straight and merges with the slightly curved posterior margin at an obtuse angle. The anterior dorsal margin is slightly concave and slopes very steeply towards the anterior end. The front end is slightly more rounded than the rear end. The ventral edge is very flat and rounded, in the middle almost straight. The ligament is long and flat and rests on a nymph behind the vertebra. The resilium bulges and the periostracum rests directly on the resilium. The lock has two small main teeth in the right flap and paired front and rear posterior teeth. In the left valve there are two main teeth and an anterior and posterior posterior tooth.
The shell is thin, fragile and translucent. The ornamentation consists of 22 to 27 radial ribs that disappear on the posterior and anterior dorsal margin. The ribs are flat and about as wide as the spaces between them. In juvenile cases, the ribs in the posterior dorsal parts are occasionally covered with blunt thorns. The inner edge of the case is notched. The color varies from reddish brown to olive. Often the ribs are darker than the spaces between them or they are covered with spots. The ribs cross with fine growth strips parallel to the edge. The periostracum is very thin.
Similar species
The triangular cockle ( Parvicardium exiguum ) is clearly (rounded) triangular. The transition from the rear edge to the ventral edge is more angled. However, both species are slightly skewed, in contrast to the lagoon cockle ( Cerastoderma glaucum ), which is almost equilateral.
Geographical distribution, habitat and way of life
The distribution area is limited to the Baltic Sea and the southern Kattegat . It stretches from Zealand to the Åland Islands. The depth distribution ranges from 0.5 meters to 37 meters of water (0 to 40 m).
The Copenhagen cockle is a typical brackish water species that only occurs in waters with a salt content of 6 to 12 ‰. In the underwater vegetation, the animals climb on the stems, branches and leaves of brown algae ( Fucus ), seaweeds ( Zostera ) and candelabrum algae ( Chara ). You don't dig in the sediment.
The Copenhagen cockle is very temperature tolerant. The shallow bays can be covered with ice for a long time in winter. In summer, the temperature in the shallow waters can rise to 30 °.
Taxonomy
The species was described in 1971 by Godtfred Høpner Petersen and Peter Russell in two papers, also comparing it with the lagoon cockle ( Cerastoderma glaucum ) and the triangular cockle ( Parvicardium exiguum ). The taxon is accepted as a valid taxon by MolluscaBase. Godtfred Høpner Petersen and Peter Russell established the genus Cerastobyssum in 1973 , with Cardium hauniense as the type species. Van Aartsen and Goud followed this taxonomic campaign, as did Markus Huber. The MolluscaBase, however, rates Cerastobyssum as a younger synonym of Parvicardium Monterosato, 1884. Cardium hauniense is also the type species of Balticardium Lambiotte, 1979, another subjective synonym of Parvicardium Monterosato, 1884.
literature
- Godtfred Høpner Petersen, Peter JC Russell: Cardium hauniense nov. sp. A new brackish water bivalve from the Baltic. Ophelia, 9: 11-13, 1971 doi : 10.1080 / 00785326.1971.10430086 .
- Godtfred Høpner Petersen, Peter JC Russel: Cardium hauniense compared with C. exiguum and C. glaucum. Proceedings of the Malacological Society of London, 39: 409-420, London 1971 doi : 10.1093 / oxfordjournals.mollus.a065123
Individual evidence
- ↑ Marine Bivalve Shells of the British Isles: Parvicardium hauniense (Petersen & Russell, 1971) (website of the National Museum Wales, Department of Natural Sciences, Cardiff)
- ↑ a b Godtfred Høpner Petersen, Peter JC Russell: The nomenclature and classification of some European shallow-water Cardium species. Malacologia, 14: 233-234, 1973. Online at www.biodiversitylibrary.org
- ↑ MolluscaBase: Parvicardium hauniense (Petersen & Russell, 1971)
- ↑ JJ van Aartsen, J. Goud: European marine Mollusca: notes on less well-known species. XV. Notes on Lusitanian species of Parvicardium Monterosato, 1884, and Afrocardium richardi (Audouin, 1826) (Bivalvia, Heterodonta, Cardiidae). Basteria, 64: 171-186, 2000 PDF
- ^ Markus Huber: Compendium of Bivalves. A full-color guide to 3,300 of the world's marine bivalves. A status on Bivalvia after 250 years of research. 901 p., 1 CD-ROM, Hackenheim, ConchBooks, 2010, p. 302.
- ↑ MolluscaBase: Cerastobyssum Høpner Petersen & Russell, 1973
- ↑ M. Lambiotte: Note sur les petites espèces européennes récentes de la famille des Cardiidae rapportées aux genres Parvicardium TA Monterosato, 1884 et Papillicardium F. Sacco, 1899, et description d'un genre nouveau, Balticardium gen. Nov. Informations de la Société Belge de Malacologie 7 (2): 39-47, 1979.
- ↑ MolluscaBase: Balticardium Lambiotte, 1979