Pinctada

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Pinctada
Pinctada margaritifera

Pinctada margaritifera

Systematics
Class : Mussels (Bivalvia)
Subclass : Autolamellibranchiata
Subclass : Pteriomorphia
Order : Pteriida
Family : Wing clams (Pteriidae)
Genre : Pinctada
Scientific name
Pinctada
Röding , 1798
On the lower right an open pearl oyster
Pinctada margaritifera

Pinctada , also known as pearl oysters, is a genus of the family of pteriidae (Pteriidae) used to order the Pteriida belongs. Some species of the genus Pinctada playa rolein the production of pearls .

features

The medium-sized to very large, slightly unevenly-hinged cases of the Pinctada species are slightly oblique-rounded to rounded-square and reach a maximum size of up to 33.5 centimeters ( Pinctada anomioides ), but are usually smaller (by seven centimeters). The cases are usually a little higher than they are long. The left flap is usually a little more arched than the right flap. The vertebra, which is curved forwards, sits almost in the middle, only slightly shifted from the center to the front end. The right flap has a byssus incision under the front ear . The edge of the lock is straight and drawn out more or less forwards and backwards; these extensions are also called ears . In the Pinctada species, the front ear is often larger than the rear ear . The lock is toothless in adulthood. The ligament lies externally or internally in a broad ligament pit.

The shell is thin to comparatively thick, so the case can be quite heavy. The shell is made up of two mineral layers, an inner aragonitic layer consisting of lamellar structures (see use), and an outer calcitic layer consisting of prismatic structures and the organic periostracum , which is very thin and decrepit. The ornamentation of the case consists of concentric, flaky lamellas, occasionally radial elements are also present.

Juvenile animals still have two sphincter muscles, of which the anterior sphincter muscle has completely disappeared in the adult animals ( monomyar ).

Similar genera

The shells of the genus Pteria are clearly slate and more egg-shaped, they usually also have a less thick shell. The back ear is also much larger or much longer, elongated like a beak. In the Pinctada species, the vertebra sits almost in the middle, in the Pteria species it is strongly shifted to the front edge.

Geographical distribution and habitat

The Pinctada species are found primarily in tropical and subtropical seas. Pinctada radiata penetrates on the eastern side of the Atlantic to the Mediterranean Sea, in the western Atlantic to Florida. In the Pacific Ocean, Pinctada fucata occurs as far as southern Japan. All Pinctada species live in shallow water to a depth of about 50 meters. The housings are attached to the hard substrate with byssus .

Taxonomy

The taxon was first described by Peter Friedrich Röding in 1798 . Type species is Mytilus margaritiferus Linnaeus, 1758 by later determination. The genus currently comprises 17 recent species, 6 of which are important for pearl farming. The Paleobiology Database only lists one fossil species.

use

Essentially six species of the genus Pinctada are used for pearl cultivation. They are:

  • Pinctada maxima (Jameson, 1901): The pearl mussel species Pinctada maxima is an extremely large mussel. It can grow to be 20 to 30 cm tall and weigh over 5 kg. It occurs in the eastern Indian Ocean to the tropical western Pacific . The pearls of this mussel, which is well suited for breeding, can grow up to 20 mm.
  • Pinctada margaritifera (Linnaeus, 1758): This mussel is native to the east coast of Africa , the Red Sea , the Persian Gulf , Indian Ocean, and the western and central Pacific region. The species consists of several subspecies, including the black-lipped pearl mussel ( Pinctada margaritifera cumingi ) from the Polynesian region. The most precious and famous pearls of antiquity (such as the legendary pearl earrings of Queen Cleopatra) are likely to come from this type of shell.
  • Pinctada radiata (Leach, 1814) is native to the Persian Gulf, Red Sea, Indian Ocean and, since the construction of the Suez Canal, in places also in the Mediterranean . Most of the pearls of antiquity were probably due to this type of shell. This species is only bred to a limited extent. However, their natural pearls still enjoy a high priority today.
  • Pinctada imbricata (Röding, 1798) The species Pinctada imbricata is the pearl mussel that produced the first pearls from the New World (America). The world discoverer Columbus found pearls of this type of shell among Indians on the coast of Venezuela . It is also known as the Atlantic pearl mussel because it is native to the western Atlantic ( Bermuda , Florida, and northern South America ). The natural stocks of this type of mussel are in many places exterminated or very endangered due to overfishing, especially since they are not cultivated.
  • Pinctada fucata (Gould, 1857) could be considered the most important pearl mussel species in the history of pearl farming. With this type of pearl mussel, the Japanese pearl breeder Mikimoto opened the world market for cultured pearls at the beginning of the 20th century. It is also known as the Akoya pearl mussel. The name Pinctada fucata is scientifically somewhat unstable. It is native to the marine waters of Japan , China , Taiwan , Vietnam, and Australia .
  • Pinctada mazatlanica (Hanley, 1855) is sometimes referred to as the La Paz pearl oyster. Probably the most famous teardrop-shaped (semi-baroque) pearl of all time, La Peregrina , is likely to come from this type of pearl oyster . The distribution area of ​​this East Pacific pearl mussel extends from the west coast of Mexico ( Baja California ) to Peru . It can reach a size of over 20 cm. Natural pearls can be over 10 mm in size. In addition to white pearls, this type of pearl shell also produces dark-colored pearls.

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. 230)
  • Markus Huber: Compendium of Bivalves. 901 S., Hackenheim, ConchBooks, 2010 ISBN 978-3-939767-28-2
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 262)
  • Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 1. XXXVIII, 489 pp., New York, 1969 (pp. N302).
  • Fritz Nordsieck : The European seashells: From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the like. Black Sea. 256 p., Stuttgart, G. Fischer 1969 (p. 41).

Individual evidence

  1. ^ Markus Huber: Compendium of bivalves. 901 S., Hackenheim, ConchBooks, 2010, ISBN 978-3-939767-28-2 .
  2. ^ Peter Friedrich Röding: Museum Boltenianum sive catalogus cimeliorum e tribus regnis naturæ quæ olim collegerat Joa. Fried Bolten, MD pd per XL. annos proto physicus Hamburgensis. Pars secunda continens conchylia sive testacea univalvia, bivalvia & multivalvia. Pp. 1–199, Hamburg, Trapp, 1798 Online at Göttinger Digitization Center (p. 166).
  3. ↑ World Register of Marine Species: Barbatia Gray, 1842 .
  4. ^ Paleobiology Database: Arca Linnaeus 1758

annotation

  1. ↑ The name pearl mussels is also used for closely related genera, as well as for the family Pteriidae and for pearl-producing mussels in general. This is why the pearl mussels that live in the sea are sometimes also referred to as sea pearl mussels, and the pearl mussels ( margaritifera ) that live in freshwater as river pearl mussels.