Arcida

Arcida
Temporal range: Lower Ordovician–Recent
Anadara from the Pliocene of Cyprus.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Subclass: Pteriomorphia
Order: Arcida
Families

11, See text.

Synonyms

Arcoida

The Arcida is an extant order of bivalve molluscs.[1] This order dates back to the lower Ordovician period. They are distinguished from related groups, such as the mussels, by having a straight hinge to the shells, and the adductor muscles being of equal size.[2] The duplivincular ligament, taxodont dentition, and a shell microstructure consisting of the outer crossed lamellar and inner complex crossed lamellar layers are defining characters of this order.[3]

Seven families are currently recognised within the order, including the well-known ark clams or ark shells in the family Arcidae.

  1. ^ Cite error: The named reference WoRMS_207 was invoked but never defined (see the help page).
  2. ^ Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 430. ISBN 978-0-03-056747-6.
  3. ^ Matsumoto, M. (2003). "Phylogenetic analysis of the subclass Pteriomorphia (Bivalvia) from mtDNA COI sequences". Molecular Phylogenetics and Evolution. 27 (3): 429–440. doi:10.1016/S1055-7903(03)00013-7. PMID 12742748.