Geukensia demissa
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Geukensia demissa |
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Geukensia demissa is a type of mussel from the mussel family(Mytilidae). It is originally located on the east coast of North America (from Nova Scotia to Florida ), but has now also been brought to the west coast of North America. It is the type species of the genus Geukensia Van den Poel, 1959.
features
The housing is elongated, with an angled dorsal edge and a concave curved ventral edge. The greatest height is in the rear third of the case. The housings are up to 10 cm long (exceptionally also up to 13 cm) and up to 4 cm high (length-width index about 2.4). The vertebrae are broadly rounded and sit behind the front end. The rear part of the case in particular is covered with strong, tightly spaced, radial ribs that give the edge of the case a finely indented appearance. Only one field at the front end and towards the ventral edge is without ribs. The periostracum is olive-brown, yellowish-brown, dark brown to black. The shell itself is gray-white and can only be seen in places where the periostracum has rubbed off. The inside is silver or bluish white and mostly iridescent .
The shell consists of a total of four layers, an inner layer of mother-of-pearl , a layer with conical aragonitic prisms , an outer layer with calcitic prisms and the organic periostracum.
Similar species
Geukensia demissa differs from its sister species Geukensia granosissima in that it has slightly fewer, more widely spaced, but smooth ribs. In geukensia granosissima the ribs are gekörnelt what the scientific species name granosissima suggesting. There are also significant molecular genetic differences.
Geographical distribution
Geukensia demissa occurs on the North American east coast from Nova Scotia in Canada to Florida in the southern United States . She was already at the beginning of the 20th century to the west coast of North America ( San Francisco Bay later, California) and some even after Baja California (State of Baja California abducted, Mexico). It has now also been found in the American state of Texas and in the Mexican states of Yucatán and Campeche as well as in Venezuela .
In the salt marshes of the American east coast, the species is a dominant fauna element of the Spartina alterniflora zone. It can occur there in very high numbers of individuals.
Way of life
The animals live half-buried in the mud of the tidal area with the front end first . They attach themselves to solid objects in the mud with byssus threads , but also to marsh and silt grass. The hatches are closed during low tide. They are separate sexes, the sex products are released into the open water in their original range from spring to early autumn (peak: midsummer). Even with a length of 12 mm, these mussels can become sexually mature. You will likely live to be over 20 years old.
Taxonomy
The taxon was established in 1817 by Lewis Weston Dillwyn as Mytilus demissus . It is the type species of the genus Geukensia Van den Poel, 1959. It also appears in more recent publications in the combination Ischadium demissum .
supporting documents
literature
- María Báez, Yajaira García de Severeyn, Héctor Severeyn: Reproductive cycle of Geukensia demissa (Bivalvia: Mytilidae) on a beach at Nazaret, El Moján, Zulia State, Venezuela. Ciencias Marinas, 31 (1A): 111-118, 2005
- Tron Soot-Ryen: A report on the family Mytilidae. Allan Hancock Pacific Expedition, 20 (1): 1-70, 1955 Online at UCS Digital Library .
- Tron Soot-Ryen: Some nomenclatural changes in the family Mytilidae. Proceedings of the Malacological Society of London, 35: 127-128, London 1963.
On-line
- Loren Coen, Keith Walter: Ribbed Mussel Geukensia demissa. 6 p., South Carolina Department of Natural Resources PDF
Individual evidence
- ^ A b Joan F. Blackwell, Louis F. Gainey, Michael J. Greenberg: Shell infrastructure in two subspecies of the ribbed mussel, Geukensia demissa (Dillwyn, 1817). The Biologica Bulletin, 152: 1-11, 1977 PDF
- ↑ SK Sarver, MC Landrum, DW Foltz: Genetics and taxonomy of ribbed mussels (Geukensia spp.). Marine Biology, 113: 385-390, 1992.
- ↑ a b M. E. Torchin, Ryan F. Hechinger, TC Huspeni, KK Whitney, KD Lafferty: The introduced ribbed mussel (Geukensia demissa) in Estero de Punta Banda, Mexico: interactions with the native cord grass, Spartina foliosa. Biological Invasions, 7: 607-614, 2005.
- ↑ María Báez, Yajaira García de Severeyn, Héctor Severeyn: Reproductive cycle of Geukensia demissa (Bivalvia: Mytilidae) on a beach at Nazaret, El Moján, Zulia State, Venezuela. Ciencias Marinas, 31 (1A): 111-118, 2005
- ^ Diane J. Brousseau: Age and Growth Rate Determinations for the Atlantic Ribbed Mussel, Geukensia demissa Dillwyn (Bivalvia: Mytilidae). Estuaries, 7 (3): 233-241, 1984.
- ↑ Lewis Weston Dillwyn: A descriptive catalog of recent shells, arranged according to the Linnæn method: with particular attention to the synonymy; in two volumes . Vol. 1, XII, 580 S., London, John and Arthur Arch, Cornhill, 1817 Online at www.biodiversitylibrary.org (p. 314)
- ↑ Van den Poel, L .: Faune malacologique du Hervien. Troisième note. Bulletin Institut Royal des Sciences Naturelles de Belgique, 35 (15): 1-26, 1959.
