Stone date
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Stone date ( Lithophaga lithophaga ) |
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| Scientific name | ||||||||||||
| Lithophaga lithophaga | ||||||||||||
| ( Linnaeus , 1758) |
The stone date ( Lithophaga lithophaga ), also sea date , sea date or date mussel , is a type of mussel from the family of mussels (Mytilidae) that digs into limestone or coral skeletons .
features
The housing is elongated with only slightly arched dorsal and ventral edges. They are up to about 95 mm long (exceptionally also up to 110 mm), with a height of about 32 mm; this gives a longitude-latitude index of about 2.9. The front end is well rounded, the rear end, which is also rounded, is slightly truncated. The housings are bulbous at the front and laterally flattened towards the rear. The vertebrae sit near the front end. The surface is largely smooth, only covered with strips of growth that can sometimes be quite coarse. The shell is comparatively thin; Outside yellowish to brownish in color, inside whitish-iridescent with a purple-pink tinge. The lock is toothless. The species is segregated. The eggs and sperm are released into the open water.
Geographical distribution. Habitat and way of life
The stone date occurs on the coasts of the eastern Atlantic from the Iberian Peninsula to Senegal, including the coastal areas of the Mediterranean. The population of Lithophaga living in the Red Sea is also assigned to the species Lithophaga lithophaga .
The animals drill into limestone with the help of a secretion secreted from their coat. The club-shaped cavities occur from the low water line to about 100 meters water depth. They feed on plankton, which they filter out of the water with the help of their gills. You never leave the self-drilled cavities any more.
development
The animals become sexually mature after about two years. The animals, which are around 2 to 3 cm long at this time, still produce a significantly smaller number of eggs than adult animals. The number of eggs that form in the gonads in one season is around 120,000 to 4.5 million. The eggs have a diameter of 82 to 135 µm (mean: 102 ± 12 µm). The sex products are released into the open water in the eastern Mediterranean from July, where fertilization takes place. Under laboratory conditions, the blastula stage formed after just five minutes . Fifteen minutes after fertilization, the gastrula was formed and the trochophoric larva was formed in about 15 hours. At the end of the trochophoric stage, the Prodissoconch I formed. This is D-shaped, with a straight dorsal edge and an almost semicircular ventral edge. It has a length of 105 µm and a height of 100 µm. From a length of 130 µm a first approach of the vortex appeared.
After 32 hours, the trochophora larvae transformed into Veliger larvae. After five to six days the vertebra (umbo) is formed and the formation of the Prodissoconch II begins, visible through the growth lines. The provinculum (preliminary stage of the lock) of the Veliger larva has 12 to 13 small teeth in the central area, six to seven teeth in the front area and seven, somewhat larger teeth in the rear area of the provinculum. The Pediveliger larva has 15 teeth in the central part of the provinculum, which now measures around 250 µm; at this size the first ligament appears. At the time of metamorphosis, the larval case (Prodissoconch I + II) measures 270 to 380 µm. The number of teeth in the central area of the Provinculum rises to 17 to 18 teeth. With a housing length of 490 µm, two large lateral teeth appeared in the rear area, and the number of teeth increases to 20 to 21 in the central part of the provinculum. The stone date can reach an age of over 50 years.
Taxonomy
The taxon was established by Carl von Linné in 1758 as Mytilus lithophagus . It is de facto the type species of the genus Lithophaga Röding, 1798, since the formal type species, Lithophaga mytuloides Röding, 1798 (by monotype) is a more recent synonym of Mytilus lithophagus Linné, 1758.
The stone date as a seafood
The stone date used to be collected and eaten intensively along the Mediterranean coasts. The stone date can only be collected by smashing the limestone into which mussels have drilled. In the recent past, this has led to intensive destruction of the rocky coastal habitats just below sea level. The subsequent heavy grazing by sea urchins prevents the habitats from being quickly populated again by the stone date.
protection
Due to the earlier strong collecting activity and the associated destruction of the rocky habitats just below the waterline, the stone date is now protected in the countries of the European Union.
Past sea level indicator
The caves are fossilized as gastrochaenolites . In the geosciences, they are used to determine previous sea level levels, as the boreholes are very concentrated in just a few meters below the waterline. However, the boreholes are not typical for a species, but rather generally for boring mussels of the genus Lithophaga and related genera.
supporting documents
literature
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 173)
- Guido Poppe and Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 p., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 49)
- 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. 228)
Individual evidence
- ↑ a b Sophia Galinou-Mitsoudi, Apostolos I. Sinis: Reproductive cycle and fecundity of the date mussel Lithophaga lithophaga (Bivalvia: Mytilidae). Journal of Molluscan Studies, 60: 371-385, 1994.
- ↑ Sophia Galinou-Mitsoudi, Apostolos I. Sinis: ontogenesis and settlement of the mussel Lithophaga lithophaga (L., 1758) (Bivalvia: Mytilidae). Israel Journal of Zoology, 43 (2): 167-183, 1997 doi : 10.1080 / 00212210.1997.10688901
- ^ 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 Göttingen Digitization Center (p. 705 as Mytilus lithophagus ).
- ↑ World Register of Marine Species: Lithophaga lithophaga (Linnaeus, 1758)
- ↑ G. Fanelli, S. Piraino, G. Belmonte, S. Geraci, F. Boero: Human predation along Apulian rocky coasts (SE Italy): desertification caused by Lithophaga lithophaga (Mollusca) fisheries: Marine Ecology Progress Series, 110: 1 -8, 1994 PDF
- ↑ Paolo Guidetti, Simonetta Fraschetti, Antonio Terlizzi, Ferdinando Boero: Effects of Desertification Caused by Lithophaga lithophaga (Mollusca) Fishery on Littoral Fish Assemblages along Rocky Coasts of Southeastern Italy. Conservation Biology, 18 (5): 1417-1423, 2004.
- ^ Convention on the Conservation of European Wildlife and Natural Habitats APPENDIX II
- ^ Fabrizio Antonioli, Marco Oliverio: Holocene Sea-Level Rise Recorded by a Radiocarbon-Dated Mussel in a Submerged Speleothem beneath the Mediterranean Sea. Quaternary Research, 45: 241-244, 1996 PDF
