Rough clam
| Rough clam | ||||||||||||
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Rough clam ( Venus verrucosa ) |
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| Scientific name | ||||||||||||
| Venus verrucosa | ||||||||||||
| ( Gmelin , 1791) |
The rough clam ( Venus verrucosa ) is a marine clam species from the clams family (Veneridae). It is the type species of the genus Venus Linnaeus, 1758., which is the eponymous group for the order of the Venerida . Also known in Italy and Croatia as sea truffle (tartufo di mare) or sea nut (noce).
features
The heavily billowing, equally-hinged housing of the rough clam is round in outline and measures up to about 7 cm in length. It is slightly unequal as the vertebrae sit slightly in front of the midline. The large vertebrae are curled forward at an angle. The almost straight to very slightly arched rear dorsal margin drops steeply towards the rear end. The anterior dorsal margin protrudes into the lunula.
The heart-shaped lunula is delimited by a distinct furrow. It is covered with radial ribs that merge into the concentric lamellae. The somewhat deepened, elongated area is clearly set off and covered with radial lines. The field of the area is slightly wider in the left flap than in the right flap. The ligament is sunk behind the vertebrae and takes up about a third of the length of the posterior dorsal margin. There are three cardinal teeth in each of the two valves. In the left valve, the central cardinal tooth is grooved and bilobed. There is also a small cusp (anterior tooth, also known as a lateral tooth or cardinal tooth) under and in front of the anterior cardinal tooth. In the right valve, the anterior and posterior cardinal teeth are grooved and bilobed. There is a very small pit under the anterior cardinal tooth. There are two sphincter muscles of roughly the same size; the posterior sphincter is only slightly larger than the anterior sphincter. The shell around the posterior sphincter is often tinted pink-brown, maroon, or light purple. The jacket bay is small and almost triangular.
The shell is thick-walled and firm. The ornamentation consists of approx. 50 strong, not entirely uniform, concentric lamellae that are bent up towards the vertebra and intersect with finer radial lines. The crossing points are smooth in the middle, but have strong knots on the front and rear edges. These nodes or "warts" are the scientific names of species verrucosa ( lat . Verrucosus out = warty). The German-language name “Raue” clams results from these appendages at the edges, which are missing in other species of clams. In the youth stage, the radial stripes are clearer and give the surface a net-like appearance. There are still fine strips of growth between the coarse lamellae. The inner edge of the ventral and front of the case are finely notched, while the inner rear edge is smooth. The periostracum is thin and glossy. The shell is yellow-brown to reddish-brown on the outside, the colors are most intense in the vertebral region and on the anterior dorsal margin. On the other hand, the inside of the bowl is shiny white.
The foot is large and tongue-shaped. The siphons are short, unevenly long and grown together.
Geographical distribution, habitat and way of life
The distribution area extends in the east Atlantic from the coasts of Norway to South Africa . It also occurs around the Cape Verde Islands , Canary Islands and Madeira, as well as in the Mediterranean .
The rough clam occurs primarily in coarse-grained sediments , but also in sandy-silty soils of the tidal range up to a depth of about 100 m. It feeds on phytoplankton , which it filters out of the water with the help of its gills. The thick shells of the rough clam are often drilled in the Mediterranean Sea by the Rocellaria dubia borer .
The rough clam is separate sexes. In southern Spain it has been observed that the spawning season lasted all year round. In other regions e.g. B. in the northern Adriatic (Trieste) it is limited to the period from December to September. In the lower Adriatic it takes place from June to October, in the Aegean from May to November. The length of the spawning season is likely to depend on the water temperature and the availability of phytoplankton. The animals can live up to 16 years in the Mediterranean.
Commercial importance
The rough clam is commercially fished in Brittany, Normandy and the Mediterranean. Several thousand tons are landed annually and sold at local fish markets. In France it is eaten raw or cooked.
Taxonomy
The species was described by Carl von Linné as early as 1758 . The taxon is the type species of the genus Venus Linnaeus, 1758.
supporting documents
literature
- S. Peter Dance, Rudo von Cosel (arrangement of the German edition): The great book of sea shells. 304 p., Verlag Eugen Ulmer, Stuttgart, 1977 ISBN 3-8001-7000-0 (p. 264)
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 325)
- Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 p., Gustav Fischer Verlag, Stuttgart 1969 (p. 127)
- Guido Poppe & Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 p., Verlag Christa Hemmen, Wiesbaden 1993 (2000, un. Reprint). ISBN 3925919104
On-line
- Marine Bivalve Shells of the British Isles: Venus verrucosa (Linnaeus, 1758) (site of the National Museum Wales, Department of Natural Sciences, Cardiff)
- Marine Species Identification Portal: Venus verrucosa (Linné, 1758)
Individual evidence
- ↑ a b minor Uschi in cucina: Tartufo di mare Venus verrucosa Linnaeus, 1758. In: www.agraria.org. Retrieved September 30, 2018 (Italian).
- ↑ C. Tirado, C. Salas, I. Marquez: Reproduction of Venus verrucosa L., 1758 (Bivalvia: Veneridae) in the littoral of Málaga (southern Spain). Fisheries Research, 63: 437-445, 2003 doi : 10.1016 / S0165-7836 (03) 00106-1
- ↑ a b Enrico Arneri, Gianfranco Giannetti, Bruno Antolini: Age determination and growth of Venus verrucosa L. (Bivalvia: Veneridae) in the southern Adriatic and the Aegean Sea. Fisheries Research, 38 (2): 193-198, 1998 doi : 10.1016 / S0165-7836 (98) 00146-5
- ^ Carl von Linné: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Pp. 1-824, Holmia / Stockholm, Salvius, 1758. Online at www.biodiversitylibrary.org (p. 685).
- ↑ MolluscaBase: Venus verrucosa Linnaeus, 1758
Web links
- Venus verrucosa Linnaeus, 1758 Conchological Society of Great Britain and Ireland, (accessed May 4, 2016).