Meiocardia

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Meiocardia
Meiocardia vulgaris (holotype, from Reeve 1845 (article Isocardia): Plate 1, Fig.2a, b [1])

Meiocardia vulgaris (holotype, from Reeve 1845 (article Isocardia): Plate 1, Fig.2a, b)

Systematics
Euheterodonta
Superordinate : Imparidentia
Order : Venerida
Superfamily : Glossoidea
Family : Tongue clams (Glossidae)
Genre : Meiocardia
Scientific name
Meiocardia
H. Adams & A. Adams , 1857

Meiocardia is a clam genus of the family of tongue shells (Glossidae). There are currently (2016) only six recent species. The oldest species come from the Danium ( Palaeogene ).

features

The equally flared, strongly inflated cases reach a size of up to six centimeters. They are approximately rounded-triangular in outline and are unequal. The strongly curled vertebrae are slightly offset towards the front end. The lunula is sunk, one area is missing.

In the heterodontic lock, there are two horizontal, lamellar and stacked cardinal teeth of different shapes and lengths in each flap, which are separated from one another by a pit. There is also a posterior lateral tooth after the posterior end in both valves. The ligament is located externally behind the vertebrae and sits in a deep pit. The lunula is sunk. The nymphs are long and protruding.

The aragonite shell is very thick-walled and stable. The inner edge of the case is smooth. The outer shell layer is homogeneous or consists of cross lamellas, the inner layer is complex-cross lamellar. The two sphincters are approximately the same size. The surface line is entire and not indented. There are no siphons . The foot is hatchet and has a byssus . Large cases are up to six inches tall. The surface is ornamented with coarse concentric pits and ridges or ribs. A sharp keel with knots extends from the umbo to the lower edge of the housing, for example to the transition from the rear edge to the ventral edge.

Geographical distribution and habitat

The species of the genus occur or have occurred worldwide. Today's species are mostly limited to the shallower water, from the low water line to a few tens of meters water depth.

Meiocardia faxeensis (Lundgren, 1867), Faxe Formation, Middle Danium

Taxonomy

Meiocardia was established in 1858 by the brothers Henry Adams and Arthur Adams as a subgenus of the genus Bucardia . Bucardia Schumacher, 1817 is a younger synonym of Glossus Poli, 1795. Henry and Arthur Adams did not identify a type species, but named four species in their description as belonging to their new subgenus: Isocardia lamarckii Reeve, 1845, Chama moltkiana Gmelin, 1791, Isocardia tetragona Adams & Reeve, 1850 and Isocardia vulgaris Reeve, 1845. Ferdinand Stoliczka later (1870) designated Chama moltkiana Gmelin, 1791, as a type species. MolluscaBase treats Meiocardia as a valid taxon within the tongue clam family (Glossidae). A number of fossil species are also included in the genus Meiocardia . Essentially the Worldwide Mollusc Species Database is followed here, with some additions from the more recent literature.

The species † Meiocardia agassizi Dall 1886 from the Miocene, which Peter Jung placed under the genus Meiocardia , is now part of the genus Glossocardia (family Trapezidae ). Also † Meiocardia carolinae Harris, 1919 (Eocene) and probably also † Meiocardia suzukii Squires & Advocate, 1986 (Eocene) belong to the genus Glossocardia .

The species Meiocardia globosa , newly established by A. Matsukuma and T. Habe in 1995, is a more recent synonym of Meiocardia cumingi (A. Adams, 1864). Bernard et al. (1993) accept Meiocardia lamarckii Adams & Reeve, 1850 as a valid taxon. The MolluscaBase, however, places Meiocardia lamarckii in the synonymy of Meiocardia moltkiana . Also Meiocardia delicata Kosuge & Kage, 1994 from MolluscaBase in the synonymy of Meiocardia moltkiana asked.

supporting documents

literature

  • Markus Huber: Compendium of bivalves. A full-color guide to 3,300 of the world's marine bivalves. A status on Bivalvia after 250 years of research. 901 p., 1 CD-ROM, Hackenheim, ConchBooks, 2010 (p. 705/6)
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 pages, Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 185)
  • Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Part N, Bivalvia 2. XXXVIII S., S.N491-951, New York, 1969 (S.N657).

Individual evidence

  1. ^ A b Lovell Augustus Reeve: Conchologia iconica, or, Illustrations of the shells of molluscous animals. vol. 2, containing monographs of the genera Corbula, Arca, Triton, Glauconome, Myodora, Ranella, Mitra, Cardium, Isocardia. London, Lovell Reeve, 1845 Online at www.biodiversitylibrary.org (Plate 1 (Isocardia), Fig.2a, b)
  2. ↑ a b Bernhard Lundgren: Palaeontologiska Iakttagelser öfver Faxekalken på Limhamn. Lunds universitets årsskrift, 1867 (VII): 1–30, Lund 1867 Online at Google Books (p. 30)
  3. ↑ 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. 461)
  4. ^ Ferdinand Stoliczka: The Pelecypoda, with a review of all known genera of this class, fossil and recent. In: Paleontologia Indica, Memoirs of the Geological Survey of India. 3, pp. I – XXII, 1–537, plates 1–50, Calcutta 1870–1871 (p. 1–222, plates 1–12: 1870, pp. I – XXII, 223–537, plate 23 –50: 1871) Online at www.biodiversitylibrary.org (pp. 106, 108)
  5. ↑ World wide Mollusc Species Database: Family Glossidae
  6. ↑ Bruce L. Clark, JW Durham: Eocene Faunas from the Department of Bolivar, Colombia. Geological Society of America Memoir 16: 1-126, 1946
  7. ^ Arthur Adams: Mollusca from the Seas of China and Japan. Annals and Magazine of Natural History, including Zoology, Botany, and Geology, 3. series, 13: 307-310, London 1858 Online at Google Books (p. 309)
  8. ↑ BW Lauridsen, M. Bjerager, F. Surlyk: The middle Danian faxes formation - new lithostratigraphic unit and a rare window into the taphonomic Danian of Denmark. Bulletin of the Geological Society of Denmark, 60: 47-60 2012 ISSN  0011-6297 PDF
  9. ↑ David Nicol: Meiocardia floridana, an overlooked Eocene pelecypod. The Nautilus, 82 (4): pp. 155-166, 1969 online at www.biodiversitylibrary.org
  10. ^ Günther Wienrich: The fauna of the marine Miocene from Kevelaer (Lower Rhine). 2. The fauna of the marine Miocene of Kevelaer (Lower Rhine). Bivalvia, Scaphopoda, Cephalopoda, Bryozoa, Annelida, Brachiopoda. Pp. 190–384, Leiden, 1999 ISBN 90-5782-021-8 (p. 252)
  11. ^ Johann Friedrich Gmelin: Caroli a Linné, systema naturae. Tom. I. Pars VI. Pp. 3021–3910, Lipsia / Leipzig, Beer, 1791 Online at www.biodiversitylibrary.org (p. 3235)
  12. ↑ p. 5 and plate 1, fig. 12, 13, 14, 15
  13. ^ FR Bernard, Ying-Ya Cai, Brian Morton: A Catalog of the Living Marine Bivalve Molluscs of China. Hong Kong University Press, Hong Kong 1993 Snippet from Google Books (p. 67).
  14. ↑ Peter Jung: Fossil mollusks from Carriacou, West Indies. Bulletins of American Paleontology 61 (269): 1-262, 1971.
  15. ↑ a b MolluscaBase: Meiocardia H. Adams & A. Adams, 1857
  16. ^ Richard L. Squires, David M. Advocate: New early Eocene mollusks from the Orocopia Mountains, southern California. Journal of Paleontology, 60 (4): 851-864, 1986 [: http://www.jstor.org/stable/1305074 JSTOR]
  17. ↑ A. Matsukuma, T. Habe: Systematic revision of living species of Meiocardia, Glossidae and Glossocardia, Trapezidae (Bivalvia). Mémoires du Muséum national d'histoire naturelle, 167: 75-106, 1995 ISSN  1243-4442
  18. ↑ a b MolluscaBase: Meiocardia moltkiana (Gmelin, 1791)

Web links

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