Small beak mussel
| Small beak mussel | ||||||||||||
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Small beak mussel ( Nuculana minuta ) |
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| Nuculana minuta | ||||||||||||
| ( OV Müller , 1776) |
The small beak mussel ( Nuculana minuta ) is a mussel species from the family of the Nuculanidae (order Nuculanida ) in the subclass Protobranchia .
features
The evenly folded, moderately inflated housing is elongated-egg-shaped and ends in a beak-like shape ( called rostrum ). The rostrum is just trimmed at the back. The vertebra sits well in front of the middle, i.e. H. the rear housing part is about twice as long as the front part of the housing. The housing is up to about 20 mm long. The anterior dorsal margin is rounded and slopes down towards the well-rounded anterior end. The posterior dorsal margin is slightly concave, the posterior ventral margin is also slightly concave. A well-marked back emanates from the vertebra. The edge is smooth. Nuculana minuta has short, overgrown siphons and therefore a slightly indented surface line.
The edge of the lock is only slightly curved or flatly angled, the angle or arch is located under the vertebra and the ligament. The front part of the lock plate is slightly convex; narrow near the vertebra and widening towards the anterior end. The rear part is long and slightly concave. In the front part of the taxodontic lock there are 15 to 18 small teeth angled towards the center of the lock, in the rear part of the lock there are 18 to 20 small teeth which are also angled towards the center of the lock. The area is short and only indistinctly marked. The lunula is long and lanceolate. The internally located ligament is opisthodic, rounded triangular in a resilifer .
The surface of the housing in the adult animal has up to about 30 coarse, concentric ribs, which are usually even more prominent towards the edge. They are crossed by very fine, radial lines. The periostracum is greenish to gray-yellow, occasionally with orange or brown bands; it flakes easily. The surface is matt or only slightly shiny. Occasionally the housing surfaces are covered with manganese deposits or even just speckled. The whitish skin is thin and brittle.
Similar Art
The large beaked clam ( Nuculana pernula ) is on average somewhat larger and also somewhat slimmer than Nuculana minuta .
Geographical distribution and habitat
The species occurs in the North Atlantic and the North Pacific . In the eastern North Atlantic, it also penetrates the North Sea and the Mediterranean Sea . The Mediterranean also marks the southern limit of distribution. In the North Pacific, the distribution area also extends from the Arctic to Japan and California in the south.
The small beak mussel lives there on silt, sand and gravel soils from about 9 to 2000 meters water depth.
Taxonomy
The taxon was introduced into scientific literature in 1776 by Otto Friedrich Müller as Arca minuta . The taxon was previously placed in the genus Leda Schumacher, 1817, a more recent synonym by Nuculana Link, 1807. Some authors divide the species into the following subspecies:
- Nuculana minuta minuta ( OV Müller, 1776), the nominate subspecies
- Nuculana minuta angusticauda Scarlato, 1981
- Nuculana minuta grandis Mörch, 1857
- Nuculana minuta magna Petrov, 1982
The World Register of Marine Species unites all subspecies under the nominate subspecies, i.e. H. does not recognize subspecies.
supporting documents
literature
- 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. 9)
- Rainer Willmann: Mussels and snails of the North and Baltic Seas. 310 p., Neumann-Neudamm, Melsungen 1989, ISBN 3-7888-0555-2 (p. 84)
- 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. 39)
On-line
Individual evidence
- ↑ Otto Friedrich Müller: Zoologiae Danicae prodromus, seu animalium Daniae et Norvegiae indigenarum characteres, nomina, et synonyma imprimis popularium. S. I-XXXII, 1-274, Havnia / Copenhagen, Hallager, 1776 Online at www.biodiversitylibrary.org (p. 247)
- ↑ World Register of Marine Species: Nuculana minuta ( OV Müller, 1776)