Protobranchia Explained

Protobranchia should not be confused with Prosobranchia.

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.^[1]

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.^[2]

Subclass: Protobranchia

• Superfamily: Nuculanoidea
  • Family: Bathyspinulidae
  • Family: Lametilidae accepted as Phaseolidae
  • Family: Malletiidae
  • Family: Neilonellidae
  • Family: Nuculanidae
  • Family: Siliculidae
  • Family: Tindariidae
  • Family: Yoldiidae

• Superfamily: Nuculoidea
  • Family: Nuculidae
  • Family: Sareptidae

• Superfamily: Manzanelloidea
  • Family: Manzanellidae
  • Family: Nucinellidae
• Superfamily: Solemyoidea
  • Family: Solemyidae

• Family: † Butovicellidae
  • Genus: † Butovicella
• Family: † Praecardiidae
  • Genus: † Slava
  • Genus: † Cardiola
• Family: † Antipleuridae
  • Genus: † Dualina
  • Genus: † Hercynella

Notes and References

1. Book: Barnes, Robert D. . 1982 . Invertebrate Zoology . Holt-Saunders International . Philadelphia, PA. 340. 0-03-056747-5.
2. 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