Marine drilling shells

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Marine drilling shells
Shipworm

Shipworm

Systematics
Subclass : Heterodonta
Euheterodonta
Superordinate : Imparidentia
Order : Myida
Superfamily : Pholadoidea
Family : Marine drilling shells
Scientific name
Teredinidae
Rafinesque-Schmaltz , 1815

The ship drilling mussels (Teredinidae), also called wood drilling mussels , shipworms or tap mussels , are a family of mussels and belong to the order of the Myida . Most species of the family drill in the wood and feed on shredded wood chips, but also to varying degrees on plankton filtered from the water . At least one species feeds primarily on chemoautotrophic (thiotrophic) bacteria. So far, nine species have been detected in Europe or European waters. Kuphus polythalamia from Southeast Asia is the longest recent clam. The worm-shaped soft body is up to 1.90 m long; however with a diameter of only about 6 cm.

features

The equally-hinged, mostly hemispherical, wide-gap housings are greatly reduced and only cover or enclose the front ends of the worm-like soft bodies. They usually drill holes in wood, which function as a living tube and are not left for life. The holes are lined with calcium carbonate . The thickness of this lining varies according to the thickness and type of wood; the structures can also be divided and have septa at the lower end. The two flaps no longer serve to protect the soft body, but have been modified to form the drilling organ. Accessory shell plates such as those found in the drilling mussels (Pholadidae) are missing, however.

The cases are only a few millimeters to 5 centimeters long. They are divided in outline by three radial furrows, in a small, mostly triangular front part, a large, highly oblique and distended middle part and a somewhat smaller, semicircular rear part (auriculum). The triangular front part starts at the top of the middle part, set off by a kink. The front part is provided with ribs that run transversely to the longitudinal axis and run parallel to the edge, also slightly curved, which are studded with spiky or thorn-like extensions. They are used to rasp off wood chips at the end of the drill hole. The vertebra sits in the dorsal area of ​​the front part of the housing. The middle part is usually only slightly ornamented with growth strips parallel to the edge, as is the rear part of the case. From the vertebrae often a narrow longitudinal pit or some radial elements run almost perpendicular to the longitudinal axis of the housing over the middle part of the housing to the ventral edge. The ligament lies internally in a small resilifer . Lock teeth are missing. There are three sphincters, a small anterior, a large posterior, and a small anterior sphincter. The foot is short and no longer has a byssus gland.

The rear part of the body turns into two long, retractable siphons, which, with exceptions, are usually not grown together. In the distal part, the siphons are half surrounded on the outside by an additional limestone plate called a pallet. The pallets consist of a stem and a semi-tubular or semi-conical leaf with the stem pointing down. The pallets are more specific than the two flaps; Insulated flaps can therefore usually not be reliably assigned to a type, and so most types are based on the different pallets, and occasionally also on the combination of pallets and flaps. The pallets are paddle-shaped, fork-shaped or also torch-shaped. The stems are short and rather thick, or very long and thin. In some types there are several nested pallets. If the siphons are withdrawn, the two semi-tubular leaves join together to form a cone and the opening of the living tube is closed.

The shell is usually thin and, like the pallets, is made of aragonite . The shell consists of an outer layer of crossed lamellas and an inner layer of complex crossed lamellas. The pallets consist mainly of calcium carbonate, but the front edge and possibly also forward-facing processes consist of the organic periostracum . It is easily rubbed off or decomposed after the animal dies. The front end of the pallets can be given a different shape without breaking.

Geographical distribution, habitat and way of life

The family is spread around the world. The marine drilling mussels mainly drill into wood and digest the wood particles, probably with the help of cellulase-producing bacteria. However, they are also suspension filter feeders. Some species have very small gills, which suggest that wood makes up most of the food here. At least one species feeds on chemoautrophic (thiotrophic) bacteria that live in or on the gills.

Recently, ship bills were also discovered on Svalbard , in −1.8 ° C cold water. It has not yet been clarified whether it is an already known species that has adapted to the cold water or a new species.

development

A broad spectrum of reproductive strategies can be observed within the marine bivalve molluscs, which is not limited to the classic strategies - few, large eggs or very many eggs. Some species produce millions of eggs that are fertilized in open water. The larvae have a long phase than planktonic Veliger larvae in which they can be transported far. Other species hatch their eggs in the mantle cavity and release the young as Veliger larvae or even as Pediveliger, which change to life on the ground or attach themselves to wood after just a few hours.

The Pediveliger larva, which has found a suitable substrate, first builds a wall of calcium carbonate around itself while it tries to remove the first wooden rasp from the base. Some species spawn only once a year, other species even several times.

Taxonomy

The family currently contains almost 80 recent species in three subfamilies and 14 genera. A number of species are also considered to be nomina dubia. The number of fossil species has not (yet) been recorded.

Fossil evidence

The oldest reliable representatives of the family are known from the Paleocene (on the other hand Kondo & Sano, 2009: Aptium ( Lower Cretaceous ).)

Traces of boring mussels in wood are not even seldom passed down in fossil form. Such trace fossils are grouped under the Teredolites . In addition to wood, a few pieces of amber have been found on deposits dating back to the Cretaceous period, which have been drilled into by a drill shell. Recently, fossil specimens of this Ichno genus from the Upper Jurassic ( Oxfordium ) have also been found in Cuba . The earliest evidence of Teredolites comes from the Lower Jurassic. Villegas de Gibert, Rojas-Consuegra and Beláustegui represent the Ichnogattung Teredolites but to the family of lithophagous molluscs (Pholadidae).

Food

A marine drilling shell ("turu"), cut out of mangrove wood, near Joanes, on the river island of Marajó , Brazil. The ship drilling shell in the photo is approx. 50 cm long.

Different types of marine clams are collected and eaten in northeastern Brazil. They are called Turu or Cupim-do-Mar . They occur mainly in the mangrove forests and are collected by men ("tiradores de turu") from the poorer sections of the population at low tide. Mostly it is the species Neoteredo reynei .

literature

  • Michael Amler, Rudolf Fischer & Nicole Rogalla: Mussels . Haeckel library, volume 5. Enke Verlag, Stuttgart 2000 ISBN 3-13-118391-8 .
  • Rüdiger Bieler & Paula M. Mikkelsen: Bivalvia - a look at the branches . Zoological Journal of the Linnean Society, 148: 223-235, London 2006.
  • Eugene V. Coan, Paul Valentich-Scott: Bivalve Seashells of Tropical West America marine Bivalve mollusks from Baja california to Northern Perú. Part 2. Santa Barbara Museum of Natural History, Santa Barbara 2012 ISBN 978-0-936494-43-2 (p. 971)
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 304/05)
  • 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. 156)
  • Guido Poppe. Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 136)
  • Ruth D. Turner: A Survey and Illustrated Catalog of the Teredinidae Harvard University, Cambridge. 1966 (without ISBN) online at www.biodiversitylibrary.org
  • Ruth D. Turner: Family Teredinidae. In: Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 2. S.N722-N742, New York, 1969.

Individual evidence

  1. Luísa MS Borges, Lucas M. Merckelbach, Íris Sampaio, Simon M. Cragg: Diversity, environmental requirements, and biogeography of bivalve wood-borers (Teredinidae) in European coastal waters. Frontiers in Zoology, 11, 13, 13 pp., 2014
  2. Eli Klintisch: Arctic shipworm discovery alarms archaeologists. Science, 351 (6276): 901 doi : 10.1126 / science.351.6276.901
  3. MolluscaBase: Teredinidae Rafinesque, 1815
  4. ^ Eugene V. Coan, Paul Valentich-Scott: Bivalve Seashells of Tropical West America marine Bivalve mollusks from Baja california to Northern Perú. Part 2. Santa Barbara Museum of Natural History, Santa Barbara 2012 ISBN 978-0-936494-43-2 (p. 912)
  5. Yasuo Kondo, Shin-ichi Sano: Origination of extant heteroconch families: Ecological and environmental patterns in post-Paleozoic bivalve diversification. Palaeontological Research, 13: 39-44, Tokyo 2009 doi : 10.2517 / 1342-8144-13.1.039
  6. E. Peñalver & X. Delclos: Spanish Amber. In: Biodiversity of fossils in amber from the major world deposits. Ed .: D. Penney, Manchester 2010
  7. ^ A. Ross, C. Mellish, P. York & B. Crighton: Burmese Amber. In: Biodiversity of fossils in amber from the major world deposits. Ed .: D. Penney, Manchester 2010
  8. ^ A b J. Villegas, JM de Gibert, R. Rojas-Consuegra, Z. Belaústegui: Jurassic Teredolites from Cuba: New trace fossil evidence of early wood-boring behavior in bivalves. Journal of South American Earth Sciences, 38: 123-128, Columbia (South Carolina, USA) 2012
  9. Bernd-Wolfgang Vahldiek, Günter Schweigert: Oldest evidence of wood-drilling mussels. New yearbook for geology and palaeontology treatises, 244: 261–271, 2007 PDF  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (Summary).@1@ 2Template: Toter Link / content2.schweizerbart.de  
  10. ^ Nigel JH Smith: Amazon Sweet Sea: Land, Life, and Water at the River's Mouth University of Texas, 2002, p. 203.