Acharax

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Acharax
Acharax gadirae

Acharax gadirae

Systematics
Class : Mussels (Bivalvia)
Subclass : Protobranchia
Order : Solemyida
Superfamily : Solemyoidea
Family : Shellfish (Solemyidae)
Genre : Acharax
Scientific name
Acharax
Dall , 1908

Acharax (. Greek α / a = not χάραξ and / charax, m = sting mandrel pole.) Is a shell - genus in the family of solemyidae (Solemyidae) from the order of the Solemyida . The oldest, certainlybelongingto the genus Acharax, come from the Albium (higher Lower Cretaceous). In 2011, John Bowman Bailey put some species from the Upper Carboniferous into the genus Acharax , which would move the earliest evidence of the genus considerably further back into geological history.

features

The housings of the Acharax species, which are of the same flaps, but are very unequal, are large to very large (up to 30 cm in length: † Acharax yokosukensis Kanie & Kuramochi, 1995). They are rounded at the back and front, oblong-egg-shaped, oblong-elliptical or with largely parallel ventral and dorsal edges. They are moderately bloated (thick) and have a gape at the front and rear ends. The vertebrae are shifted towards the rear end; these are small and collide.

There is no lunula , the area is quite large. The edge of the case is quite sharp and is formed by the periostracum , which is often torn or already torn off. The ligament is completely external and lies in front of and behind the vertebrae. There is no ligament support. The lock is toothless.

The mineral skin is whitish, moderately thick to thin, and consists of aragonite . The comparatively thick organic periostracum , firmly adhering to the mineral shell, protrudes well beyond the edge of the mineral shell. The surface has broad radial ribs separated by shallow recessed strips.

There are two sphincters, but the front one is significantly larger than the rear sphincter. The insertion of the posterior sphincter is slightly sunk into the shell.

Geographical distribution and way of life

The genus is distributed worldwide. The Acharax species are distinct deep-sea forms (deeper than 400 meters to around 5,000 meters) that occur on cold seas or in sediments that are influenced by rising hydrothermal waters. Acharax also occurred in the Mediterranean during the Miocene and Pliocene.

All species of the genus Acharax feed on chemoautotrophic, sulfide-oxidizing bacteria in the gill tissue. The development takes place via z. Sometimes very large, yolk-rich eggs and a special non-planktotrophic larva (Pericalymma larva).

Taxonomy

The taxon was established in 1908 by William Healey Dall . The type species is Solemya johnsoni Dall, 1891. The World Register of Marine Species currently assigns ten recent species to the genus. There are also some fossil species; the Paleobiology Database is very incomplete in this regard.

Carter 1990 divided the genus Acharax into two subgenera: Acharax (Acharax) and Acharax (Nacrosolemya) Carter, 1990.

supporting documents

literature

  • Markus Huber: Compendium of bivalves. 901 S., Hackenheim, ConchBooks, 2010 ISBN 978-3-939767-28-2
  • Gennady M. Kamenev: North Pacific species of the genus Solemya Lamarck, 1818 (Bivalvia: Solemyidae), with notes of Acharax johnsoni (Dall, 1891). Malacologia, 51 (2): 233-261, 2009 PDF
  • Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Bivalvia 1. XXXVIII, 489 pp., New York, 1969 (pp. N243).

Individual evidence

  1. ↑ a b c d e John Bowman Bailey: Paleobiology, Paleoecology, and Systematics of Solemyidae (Mollusca: Bivalvia: Protobranchia) from the Mazon Creek Deposit, Pennsylvanian of Illinois. Bulletins of American Paleontology, 382: 1-61, 2011 PDF ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.museumoftheearth.org
  2. ↑ a b c Kazutaka Amano, Hisao Ando: Giant fossil Acharax (Bivalvia: Solemyidae) from the Miocene of Japan. The Nautilus, 125 (4): 207-212, 2011 PDF
  3. ^ William Healey Dall: A revision of the Solenomyacidae. The Nautilus, 22 (1): 1–2, 1908 Online at www.biodiversitylibrary.org (p. 2)
  4. ^ World Register of Marine Species: Acharax Dall, 1908
  5. ^ Paleobiology Database: Acharax Dall 1908
  6. ↑ a b c Yasumitsu Kanie: Review of the family Solemyidae (Mollusca: Bivalvia) from Japan, and description of the new species. Science Report of the Yokosuka City Museum, 49: 49-60, 2002, ISSN  0513-2622 (only viewed abstract)
  7. ↑ a b c Steffen Kiel, Kazutaka Amano, Robert G. Jenkins: Bivalves from Cretaceous cold − seep deposits on Hokkaido, Japan. Acta Palaeontologica Polonica. 53 (3): 525-537, 2008 PDF
  8. ^ A b Marco Taviani, Lorenzo Angeletti, Alessandro Ceregato: Chemosynthetic Bivalves of the Family Solemyidae (Bivalvia, Protobranchia) in the Neogene of the Mediterranean Basin. Journal of Paleontology, 85 (6): 1067-1076, 2011. doi : 10.1666 / 10-119.1
  9. ↑ Ellen James Moore: Miocene Marine Mollusks from the Astoria Formation in Oregon. Geological Survey Professional Paper, 419: Washington 1976 Online at Google Books (p. 51)
  10. ↑ John G. Carter: Chapter 10. Evolutionary significance of shell microstructure in the Palaeotaxodonta, Pteriomorphia and Isofilibranchia (Bivalvia Mollusca) . In: John G. Carter (Ed.): Skeletal Biomineralization: Patterns, Processes and Evolutionary Trends. Pp. 135-296, Van Nostrand Reinhold, New York 1990.

Web links

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