Chlamys (genus)

Chlamys swifti

Chlamys is a genus of scallops ( Pectinidae ) in the order of Pectinoida within the class of mussels ( Bivalvia ). You live or lived exclusively in the sea. The oldest representative of the genus are known from the Triassic. Many species are intensively fished and are of high commercial importance.

Features

The housings are usually higher than long. Both valves are convex; usually the left door is a bit more curved. The front ear is greater than the posterior ear. Below the anterior ear of the right valve there is a large Byssusloch. The outside is covered with numerous, spiny ribs or beads, wherein the beads are again occupied by finer radial ribs. These radial elements can be crossed by concentric Anwachsrippen and beads. The inner edge has fine radial ribs. The Cruren, small projections on the castle are poorly developed or absent. The shells are conspicuously colored, colorful in many ways. The coloring can orange, yellow, pink, purple, be brown or white.

Striking feature of the soft body are arranged in rows of eyes that are recognizable as black pigment spots in the mantle fold in the living animal. The animals use their eyes to detect approaching predators, but probably also for orientation during swimming behavior.

Chlamys species are separate - gender, the ratio males to females is 1:1 or close to it.

Development

The development has been studied in various ways, for example in Chlamys hastata. From the approximately 70 microns wide, the fertilized egg hatches a free-swimming larval stage, the trochophore. This begins from two dorsal shell fields after about 45 hours of development secrete shell material. After 50 hours, the conversion to the equally free-swimming, planktonic veliger larva is complete. This has its name after the velum, an oval, lobed, occupied ciliated organ that is used both for locomotion as to acquire food. After about 34 days, the foot has been developed, the larvae crawl now often around on the substrate surface, as well as also both muscles cilia can be used. The larval development is completed in about 40 days, the shell length is then about 240 microns. In a rapid metamorphosis evolve from small gill systems, the functional gills, mouth and feet wander in the imaginal situation.

For commercial harvest of sufficient size ( about 6 inches ) is reached after 5 to 6 years. The animals can, however, achieve a life aged 28 to 30 years, maximum 35 years, you are then about 8 inches tall.

Ecology

Chlamys species living on the seabed on hard substrates, often on sandy ground with individual stones on which they anchor themselves with byssus threads. You can solve in the case of unfavorable conditions of the anchorage. How many Pectinidae they are buoyant, but not swim as often and as active as other species of the family (usually with smooth shells). When swimming, breathing water is squeezed on both sides of the castle, so that DasTier swims with the lock to the rear .. The animals come from the surf zone to a maximum of approximately 2,000 meters water depth, but usually only up to about 120 to 200 meters depth before.

Taxonomy

The old broad genus Chlamys was divided into numerous sub-genera, which are now mostly regarded as an independent species. The former genus has been confirmed by molecular studies as paraphyletic.

The genus in the modern sense only includes the former subgenus Chlamys s.str. with the following living ( extant ) species:

• Chlamys albida ( Arnold, 1906)
• Chlamys behringiana ( Middendorff, 1849)
• Chlamys chosenica Kuroda, 1932
• Chlamys hastata (G. B. Sowerby II, 1843)
• Chlamys islandica (O. F. Müller, 1776). Type species of the genus
• Chlamys rubida ( Hinds, 1845)

The types Zygochlamys subantarctica Hedley, 1916, and Zygochlamys delicatula Hutton, 1873 ( syn. Chlamys campbellicus, Chlamys instar ) are still run by some authors in the genus Chlamys. The names of species Chlamys russata ( Reeve, 1853) (probably a synonym of Pinna exquisita Dall, Bartsch & Rehder, 1938) and Chlamys reticulata ( Reeve, 1853) in their assignment unclear ( nomen dubium, species inquirenda ).

The numerous other species that had been earlier times in genus are attributed to other genera currently.

Dissemination

The genus Chlamys in here illustrated, the modern sense is restricted to the North Pacific and North Atlantic, it is widespread in boreal and Arctic waters. The genus is widespread and zirkumploar, but the individual species have significantly smaller distribution areas. They are often regional, but in many shallow-water stocks due to overfishing have become much less common today.