Pinnidae

Various pen shells, from left to right: Pinna muricata, Atrina pectinata, Atrina vexillum, Pinna bicolor

The pen shells ( Pinnidae ) belonging to the class of mussels ( Bivalvia ), put their lives in hard ground between boulders, water plants or corals. This means they are sessile animals. With the byssus, a silky braid that secretes the shell from a special gland, they anchor themselves to the ground or gravel. The byssus is albuminous and liquid, but is in contact with the salt water tear-resistant threads. The mussel feeds by filtered plankton from the water.

Most species are not older than ten years, but there is one exception: the indigenous in the Mediterranean noble pen shell, Pinna nobilis is the longest-running and largest Steckmuschelart. It can be up to 20 years old and up to 90 cm tall. However, there have also been found copies with a shell length of about 130 cm.

Shell shape

The usually 10 to 30 cm shells have a paddle-like, tapered shape, which are narrow and elongated or broad and short depending on the type. They are usually thin and fragile and have at the rear edge damaged, as this may be protruding from the ground and therefore slightly injured. These signs of aging reduce the value of the shell in collector circles but not dramatically, since they are normal and rarely a pen shell perfectly preserved is retrieved from the water.

List of species

The pen shells are divided into three different genera: Pinna narrow bowl, the wider Atrina species and the irregularly shaped genus Streptopinna, but only one known type adduced, which means it is monotypic. There are about 30 different known species. Here are the most common types are listed below:

Pinna Linnaeus, 1758

  • Pinna atropurpurea Sowerby, 1825
  • Pinna attenuata Reeve, 1858
  • Pinna bicolor Gmelin, 1791
  • Pinna carnea Gmelin, 1791
  • Pinna incurva Gmelin, 1791
  • Pinna inflata Wood
  • Pinna muricata Linnaeus, 1758
  • Pinna nobilis Linnaeus, 1758 Shells of the noble pen shell, left the outside, the inside of the right
  • Pinna rudis Linnaeus, 1758
  • Pinna rugosa Sowerby, 1835

Katrina Gray, 1840

  • Katrina chautardi Nickelés, 1953
  • Atrina fragilis ( Pennant, 1777)
  • Katrina kinoshitai Have, 1953
  • Katrina maura ( Sowerby, 1835)
  • Atrina pectinata (Linnaeus, 1776)
  • Atrina pectinata zelandica (Gray, 1835) ( New Zealand form of Atrina pectinata. )
  • Katrina rigida ( Lightfoot, 1786)
  • Katrina seminuda ( Lamarck, 1819)
  • Katrina serrata (G. B. Sowerby I. 1825)
  • Katrina squamifera ( Sowerby, 1835)
  • Katrina tasmanica ( Tenison & Woods, 1876)
  • Katrina teramachii Have, 1953
  • Katrina tuberculous ( Sowerby, 1835)
  • Katrina vexillum (Born, 1778)

Streptopinna Martens, 1880

  • Streptopinna saccata (Linnaeus, 1758)

Reproduction

Pen shells reproduce like all other shells, ejection by the female egg and the male mussels mussels sperm. So it is in the water to fertilize the eggs. After the larval stage, with pen shells of veliger type, is caused by a metamorphosis, the young mussel that already attach to the substrate and " grow into" the ocean floor.

Dissemination

Pen shells come in all oceans before, from the Mediterranean to the Indo-Pacific and the Caribbean. Most Atrina species occur in the Indo-Pacific and the Caribbean before being Pinna some species, such as Pinna nobilis ( noble pen shell) or Pinna rudis ( Rough Penshells ) are found only in the Mediterranean. However, all kinds stuck with the pointed end in the sediment and are found only up to a water depth of approximately 100 m.

Use

Pen shells are not the most well-known mussel species among the laity (non- Conchyliensammler or non - zoologists ), and in Europe today rarely processed. It used to be made ​​from the fine, silky byssus threads which secretes the shell, posh clothing or even pictures here. However, this craft only mastered a woman in Sant'Antioco in Sardinia. The types Atrina pectinata and Atrina kinoshitai are now commonly offered in Japan in fish markets as food animals. In Europe, the local noble pen shell but was also used for food purposes, therefore, also referred to as " Penshells ". However, the mussel is still a popular collectible pieces, as they will rarely offered for sale mainly.

Species protection

Pen shells are found quite frequently in tropical seas, but is living in the Mediterranean noble pen shell ( Pinna nobilis) become rare due to overfishing and water pollution. That is why they put in throughout the European Union and Croatia under protection and may no longer be imported into Germany by the Federal Nature Conservation Act. Those who ignore this must reckon with a fine.

William Elford Leach
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