Noble pen shell
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Noble pen shell ( Pinna nobilis ) |
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| Linnaeus , 1758 |
The noble pen shell , or Large pen shell ( Pinna nobilis ) is a shell - type from the family of pen shells (Pinnidae). With a shell that is up to 1.2 meters in length, it is one of the largest mussel species in the world; however, it is usually much smaller (60 to 90 cm).
features
The same-folding large to very large housing of the noble pen shell is fan-shaped or paddle-shaped with a pointed front end and a truncated or flat-semicircular rear end. It becomes 60 to 90 cm long (exceptionally up to 120 cm). The small vertebrae sit at the very front end. The ventral and dorsal edges are straight. The housing gapes at the rear end, but the gap can almost be closed by the sphincter, as the shell is slightly flexible. The case is quite flat in relation to the width (about three times as wide as it is thick). In the middle of the housing, a ridge extends from the front to the rear end, the cross-section of the housing is then often rhombic. The lock is toothless. The ligament is very long, lies in a groove (sub-internal) and extends over almost the entire dorsal margin. The byssus is strong.
The mineral skin is thin, often transparent and somewhat flexible. It consists of the inner aragonitic mother-of-pearl layer and an outer calcitic prism layer . The inside of the shell often has a slightly reddish sheen. The ornamentation on the outside consists of about 20 ribs extending from the front end, on which scales or short hollow spines sit. In large specimens, the ribs can also be missing or gradually lose themselves. In juvenile animals and on the juvenile part of adult animals, strong streaking can also be observed on the front part of the housing. The organic periostracum is horn-colored, orange-brown, red-brown or flesh-colored. Due to the constant corrosion of the front end stuck in the sediment, the outermost front end can be lost. The resulting gap is sealed with transverse walls (septa), and the anterior sphincter muscle moves slightly towards the posterior margin.
The anterior sphincter is quite small and the posterior sphincter is quite large. In relation to the width of the case, it is slightly anterior to the case, and in relation to the length of the case and living position, it is still in the lower half of the case.
Geographical distribution, habitat and way of life
The range of the noble pen shell extends over the entire Mediterranean. It mostly lives in sandy seagrass meadows near the coast ( Zostera and Posidonia communities) in three to ten meters water depth. But it can also occur at greater depths (up to about 60 m). The animals stick upright with their tips in the sediment. The housing protrudes from the sediment by about one to two thirds. It anchors itself with byssus threads on stones, shell fragments or the rhizomes of the seaweed in the sandy seabed. The threads, which are up to 20 cm long, arise from the protein-containing secretion of a gland on the animal's foot (byssus gland), which solidify into solid threads on contact with the salty water; they are extremely fine and tear-resistant (see Byssus ). The noble pen shell filters plankton from the water. It needs clean water, good lighting and a steady, light current. The noble pen shell has become rare not only through the collection, but also through the pollution of the coastal areas of the Mediterranean Sea.
Reproduction
The life cycle of the noble pen shell has not yet been adequately researched. The animals are protandric hermaphrodites , but usually males or females, true hermaphrodites are rare. Female animals only form from an enclosure size of 44.5 cm and above. The animals can change their sex within a few days; larger females can also become males again. In experiments in the laboratory, after a temperature shock, the females released an average of over 725,000 eggs into the free water, where they were artificially fertilized. The eggs are about 50 µm in diameter. Swimming larvae were not observed until one day after fertilization, which could indicate that the eggs are fertilized under natural conditions in the mantle of the females and that the larvae are retained between the gills until they are able to swim. In some specimens, spawning again could be observed within a few days. After two days the larva had reached the planktotrophic Veliger stage; the D-shaped prodissoconch had been formed. The larvae could be kept alive for up to 25 days. However, a presumably bacterial infection had already destroyed the vela and the larvae could no longer eat. In nature, the larvae return to soil life after about five to ten days and transform into young mussels. The young mussels then grow very quickly with up to a little over ten centimeters per year and reach sexual maturity and a shell size of a little over 40 cm at around four years of age. After that, growth slows down by about three centimeters per year. They can live to be more than 25 years old.
Taxonomy
The taxon was proposed by Carl von Linné in 1758 . MolluscaBase lists numerous synonyms : Pinna aculeatosquamosa Martens, 1866, Pinna cornuformis Nardo, 1847, Pinna ensiformis Monterosato, 1884, Pinna gigas Röding, 1798, Pinna incurvata Born, 1778, Pinna nigella Gregorio, 1885, Pinna nobilis var. Aequilatera , 1867, Weinkauff, 1867 Pinna nobilis var. Dilatata Pallary, 1906, Pinna nobilis var. Gangisa de Gregorio, 1885, Pinna nobilis var. Intermilla de Gregorio, 1885, Pinna nobilis var. Latella de Gregorio, 1885, Pinna nobilis var. Magus de Gregorio, 1885, Pinna nobilis var. nana Pallary, 1919, Pinna nobilis var. pisciformis de Gregorio, 1885, Pinna nobilis var. polii Bucquoy, Dautzenberg & Dollfus, 1890, Pinna nobilis var. rarisquama Bucquoy, Dautzenberg & Dollfus, 1890, Pinna Obeliscus Martens, 1866 Pinna squammosa Requien, 1848 and Pinna squamosa Gmelin, 1791.
Seafood and other uses
The noble pen shell is an edible shell. It used to be caught with special fishing irons and consumed as seafood. In Greece the sphincters (of several mussels) were put on wooden skewers and grilled or the whole mussel (without shell) was dusted with flour and fried in olive oil. Today it is protected and can no longer be caught.
Shell silk has been made from the shimmering golden byssus threads of the shell since ancient times , and was coveted as an extremely valuable fabric well into the Middle Ages and early modern times. A mussel provides only about one to two grams of raw byssus, approx. 20,000 very fine threads up to 25 cm long. For one kilogram of pure mussel silk it was necessary to harvest up to 4,000 animals. The shell silk is shiny and can only be dyed with difficulty. The craft of shell silk spinning was probably brought to Sardinia by the Phoenicians . At the medieval royal courts, the shell products with their shiny gold silk threads were valued. In modern times it reached its peak in the 18th and 19th centuries.
“I immediately put on my linen clothes. Conseil often made his observations about the nature of this material. I now instructed him that it was made of the shiny, silk-like fibers, with which a species of mussels is very often attached to the rocks on the shores of the Mediterranean Sea. "
symbiosis
The noble pen shell often houses small decapods of the species Pontonia pinnophylax or Nepinnotheres pinnotheres in the shell space than symbionts . They used to be called mussel guards .
protection
Overfishing and water pollution have made the mussels, which used to be common, have become rare. It is therefore protected throughout the European Union .
Trivia
In 1970, the Algerian Post issued a stamp showing the noble pen shell in its living position. In 1997, the Croatian Post issued a stamp series on the local fauna as well.
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. 229)
- Rosina Fechter, Gerhard Falkner: Mollusks. 287 p., Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10), ISBN 3-570-03414-3 (p. 80)
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 251/2)
- 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. 42)
- Guido Poppe and Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 55)
On-line
- Encyclopedia of Life
- La Grande Nacre de Méditerranée: Pinna nobilis L. (1758) - site dedicated to the noble pen shell (French)
Individual evidence
- ↑ D. Zavodnik, M. Hrs-Brenko, M. Legac: Synopsis on the fan shell Pinna nobilis L. in the eastern Adriatic Sea. In: CF Boudouresque, M. Avon, V. Gravez, (Eds.): Les Espèces Marines à Protéger en Méditerraneé , pp. 169–178, GIS Posidonie publications, Marseille 1991.
- ↑ Béatrice de Gaulejac, M. Henry, N. Vicente: An ultra-structural study of gametogenesis of the marine bivalve Pinna nobilis (Linnaeus 1758) 1. Oogenesis. Journal of Molluscan Studies, 61: 375-392, 1995
- ↑ S. Trigos, N. Vicente, JR García-March, J. Torres, J. Tena: embryo Logical Development of Pinna nobilis in Controlled Conditions. Marine Productivity: Perturbations and Resilience of Socio-ecosystems, 2015: 369-371, 2015 ISBN 978-3-319-13877-0 doi : 10.1007 / 978-3-319-13878-7_42
- ↑ José Rafael García-March, Antonio Manuel García-Carrascosa, Álvaro Luís Peña: In Situ Measurement of Pinna nobilis Shells for Age and Growth Studies: A New Device. Marine Ecology, 23 (3): 207-217, 2002
- ^ 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, Holmiae / Stockholm, Salvius, 1758. Online at Göttinger Digitization Center (p. 707).
- ↑ MolluscaBase: Pinna nobilis Linnaeus, 1758
- ↑ Jules Verne: Twenty Thousand Leagues Under the Sea. First volume, chapter 16 .
- ↑ Miguel Cabanellas-Reboredo, Andreu Blanco, Salud Deudero, Silvia Tejada: Effects of the invasive macroalga Lophocladia lallemandii on the diet and trophism of Pinna nobilis (Mollusca: Bivalvia) and its guests Pontonia pinnophylax and Nepinnapoda pinnotheres (Crustacea). Scientia marina, 74 (1): pp. 101–110, 2010 PDF .
- ↑ FAUNA HRVATSKOG PODRUČJA - PLEMENITA PERISKA. Retrieved August 1, 2019 .
