Protobranchia is a subclass of

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biv ...

molluscs. It contains the extant

orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

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. Subclass: Protobranchia

Order: Nuculanida

*Superfamily: Nuculanoidea **Family: Bathyspinulidae **Family:

Lametilidae Lametilidae is a family of bivalves. The family is related to the nut clams ( Nuculidae). Taxonomy * '' Lametila'' ** '' Lametila abyssorum'' * ''Phaseolus ''Phaseolus'' (bean, wild bean) is a genus of herbaceous to woody annual and perennia ...

accepted as

Phaseolidae Phaseolidae is a family of bivalves belonging to the order Nuculanida. Genera: * '' Lametila'' Allen & Sanders, 1973 * ''Phaseolus ''Phaseolus'' (bean, wild bean) is a genus of herbaceous to woody annual and perennial vines in the family Faba ...

**Family: Malletiidae **Family: Neilonellidae **Family: Nuculanidae **Family: Siliculidae **Family: Tindariidae **Family:

Yoldiidae Yoldiidae is a taxonomic family of small to medium-sized saltwater clams, marine bivalve molluscs in the order Nuculanida. Genera and species Genera and species within the family Yoldiidae include: * '' Megayoldia'' ** '' Megayoldia martyria' ...

Order: Nuculida

*Superfamily: Nuculoidea **Family: Nuculidae **Family: Sareptidae

Order: Solemyida

*Superfamily: Manzanelloidea **Family: Manzanellidae **Family: Nucinellidae *Superfamily: Solemyoidea **Family:

Solemyidae Solemyidae is a family of saltwater clams, marine protobranch bivalve mollusks in the order Solemyida. Biology Solemyids are remarkable in that their digestive tract is either extremely small or non-existent, and their feeding appendages are to ...

Order: †
Praecardiida Praecardiida is an extinct order of fossil saltwater clams, marine bivalve mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,00 ...

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

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