Acesta (genus)

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Acesta
Acesta excavata

Acesta excavata

Systematics
Subclass : Pteriomorphia
Order : Limida
Superfamily : Limoidea
Family : File clams (Limidae)
Subfamily : Liminae
Genre : Acesta
Scientific name
Acesta
H. Adams & A. Adams , 1858

Acesta is a shell - genus from the family of limidae (Limidae). The oldest species of the genus are known from the Upper Jurassic .

features

The unequal-sided, but equilateral, moderately thick and large to very large cases are egg-shaped in outline, and higher than long (broad). In some species they can reach a size (height) of up to 25 centimeters. The vertebra is slightly off the center. The ears are very uneven. While the front ear is greatly reduced or missing completely, the rear ear is usually quite large and triangular, but often only indistinctly separated from the body of the case. The front edge is usually bevelled or slightly concave, the rear dorsal edge is moderately convex. At the anterior border between the anterior end and the vertebrae the two valves gape more or less clearly; here the byssus comes through. The lock is behind the vertebra, it's toothless. The ligament pit is deeply sunk and curved.

The shell is comparatively thin, but firm. It consists of two different mineral layers, consisting of an inner aragonitic layer and an outer calcitic layer. The ornamentation is not very pronounced and consists of fine radial lines and fine, often somewhat coarser strips of growth. The periostracum is very thin and often rubbed off in the vertebral area and middle part of the housing body.

There is only one sphincter (the back one). Often the impression of the foot retraction muscle can also be seen on the inside of the valve. The surface line is entire without indentation.

Geographical distribution and way of life

The genus Acesta is common worldwide. All species of acesta live in cold water habitats either in arctic waters or in deep water areas of otherwise subtropical and tropical oceans. The depth range in which the genus Acesta occurs therefore extends from about 30 meters water depth to presumably into the deep sea. They are epifaunistic filter feeders who attach themselves to hard substrates with byssus threads.

Taxonomy

The taxon was established by the brothers Henry and Arthur Adams in 1858 . Type species is Ostrea excavata Fabricius 1779. The World Register of Marine Species and the Paleobiology Database provide the following recent and fossil species to the genus Acesta Adams & Adams, 1858:

The World Register of Marine Species treats Plicacesta Vokes, 1963 and Callolima Bartsch, 1913 as synonyms of Acesta Adams & Adams, 1958.

supporting documents

literature

  • Matthias López Correa, André Freiwald, Jason Hall-Spencer, Marco Taviani: Distribution and habitats of Acesta excavata (Bivalvia: Limidae) with new data on its shell ultrastructure. In: André Freiwald, JM Roberts (Ed.): Cold-water Corals and Ecosystems , pp. 173-205, Springer Verlag, Berlin, Heidelberg 2005 PDF
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 12)
  • Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 1. XXXVIII, 489 pp., New York, 1969 (pp. N386 / N387).
  • 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. 59)

Individual evidence

  1. ^ Henry Adams & Arthur Adams: The genera of recent Mollusca; arranged according to their organization. In three volumes. Vol. II. Pp. 1–661, London, Van Voorst, 1858. Online at www.biodiversitylibrary.org (p. 545)
  2. ^ A b c World Register of Marine Species: Acesta H. Adams & A. Adams, 1858
  3. ^ Paleobiology Database: Acesta Adams and Adams 1858
  4. ↑ Jeffrey D. Stilwell, E. Donald McKenzie: First record of Acesta (Bivalvia: Limidae) from the Cretaceous of Australia. Alcheringa: An Australasian Journal of Palaeontology, 23 (4): 283-288, 1999 doi : 10.1080 / 03115519908527811
  5. ↑ a b c Ellen James Moore: Tertiary Marine Pelecypods of California and Baja California: Plicatulidae to Ostreidae. United States Geological Survey Professional Paper, 1228-C: Washington, 1987 PDF
  6. ↑ Mitsuo Nakano, Kazuo Okamoto: A new species Acesta (Plicacesta) watanabei from the Miocene in Southwest Japan. Transactions and Proceedings of the Palaeontological Society of Japan, new series, 127: 357-363, Tokyo 1982 PDF

Web links

Commons : Acesta  - collection of images, videos and audio files