Protobranchia is a subclass of bivalve molluscs. It contains the extant orders Nuculanida, Nuculida, and Solemyida.
These are deep water clams of a small and primitive order with a taxodont hinge (composed of many similar, small teeth), generally with a central ligament pit, large labial palps which are used in deposit feeding and the gills used only for respiration, the anterior and posterior adductor muscles are nearly equal in size, a foot which is divided sagittally and longitudinally with papillate margins. The foot in Protobranchia clams is without a true byssus gland, although they frequently have a nonhomologous byssal gland in the heel. The byssal gland in these clams does not produce threads as in Pteriomorphia.
2010 Taxonomy
In 2010 a new proposed classification system for the Bivalvia was published in by Bieler, Carter & Coan revising the classification of the Bivalvia, including the subclass Protobranchia.3
Subclass: Protobranchia
Order: Nuculanida
Source:4
- Superfamily: Nuculanoidea
- Family: Bathyspinulidae
- Family: Lametilidae accepted as Phaseolidae
- Family: Malletiidae
- Family: Neilonellidae
- Family: Nuculanidae
- Family: Siliculidae
- Family: Tindariidae
- Family: Yoldiidae
Order: Nuculida
Source:5
- Superfamily: Nuculoidea
- Family: Nuculidae
- Family: Sareptidae
Order: Solemyida
Source:6
- Superfamily: Manzanelloidea
- Family: Manzanellidae
- Family: Nucinellidae
- Superfamily: Solemyoidea
- Family: Solemyidae
Order: † Praecardiida
- Family: † Butovicellidae
- Genus: † Butovicella
- Family: † Praecardiidae
- Genus: † Slava
- Genus: † Cardiola
- Family: † Antipleuridae
- Genus: † Dualina
- Genus: † Hercynella
References
Protobranchia Pelseneer, 1889. Retrieved through: World Register of Marine Species on 8 July 2010. http://www.marinespecies.org/aphia.php?p=taxdetails&id=106 ↩
Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 340. ISBN 0-03-056747-5. 0-03-056747-5 ↩
Bieler, R., Carter, J.G. & Coan, E.V. (2010) Classification of Bivalve families. Pp. 113-133, in: Bouchet, P. & Rocroi, J.P. (2010), Nomenclator of Bivalve Families. Malacologia 52(2): 1-184 ↩
Nuclanoida Carter, D.C. Campbell & M.R. Campbell, 2000. Retrieved through: World Register of Marine Species on 9 October 2010. http://www.marinespecies.org/aphia.php?p=taxdetails&id=203 ↩
Nuculida Dall, 1889. Retrieved through: World Register of Marine Species on 20 September 2010. http://www.marinespecies.org/aphia.php?p=taxdetails&id=382247 ↩
Solemyoida Dall, 1889. Retrieved through: World Register of Marine Species on 9 July 2010. http://www.marinespecies.org/aphia.php?p=taxdetails&id=22629 ↩