Protobranchia
| Protobranchia | ||||||||
|---|---|---|---|---|---|---|---|---|
Acila cobboldiae |
||||||||
| Systematics | ||||||||
|
||||||||
| Scientific name | ||||||||
| Protobranchia | ||||||||
| Pelseneer , 1889 |
The Protobranchia or Protobranchiata ( Urkiemer ) are a large group of Bivalvia ( mussels ), which in the newer classifications is listed as superclass , subclass or infraclass . It is a relatively small group of mussels. She is a sister group to Autolamellibranchiata ( Eigenblattkiemer ), which includes the vast majority of Muscheltaxa.
characterization
The cases of the Protobranchia are relatively small and mostly single-sided. The shells are aragonitic with a layer of mother-of-pearl and sometimes a layer of homogeneous microstructures, which are then overlaid by the organic periostracum. The lock is originally taxodont, and in a few derived forms it is also toothless. A special form of larvae, a peculiarity in the stomach (without a solid crystal stem) and the palp proboscids on the labial palps (palpitations) are considered to be derived and thus apomorphic . The ligament is external or internal. Most representatives of the protobranchia are isomyar, i. H. the two sphincters are approximately the same size, few shapes have unequal sphincters. The gills are protobranch, which is probably the original state of the gills in the mussels.
Systematics
The Protobranchia are the sister group of the Autolamellibranchiata in cladistics. The Protobranchia appear as an infra-class, sub-class or as a taxon without rank in the classifications. They are best classified as part, infra, or subclass. The Protobranchia contain two or three orders, whereby the order Nuculanida was established only recently and has not yet found general recognition. The relationship between the three orders has not yet been secured, so that no further subdivision is necessary.
Protobranchia Pelseneer , 1889
- Order Nuculida Dall , 1889
- Superfamily † Fordilloidea Pojeta, 1975
- Superfamily Pristiglomoidea Sanders & Allen, 1973
- Superfamily Nuculoidea Gray , 1824
- Superfamily † Ctenodontoidea Wöhrmann , 1893
- Order Solemyida Dall , 1889
- Superfamily Solemyoidea Gray , 1840
- Superfamily Manzanelloidea Chronic, 1952
- (Order Nuculanida Carter, Campbell & Campbell, 2000) (the groups classified here can also be placed in a superfamily Nuculanoidea within the order Nuculida)
- Superfamily Nuculanoidea Adams & Adams , 1854
literature
- Michael Amler, Rudolf Fischer & Nicole Rogalla: Mussels . Haeckel library, volume 5. Enke Verlag, Stuttgart 2000 ISBN 3-13-118391-8 .
- Rüdiger Bieler & Paula M. Mikkelsen: Bivalvia - a look at the branches . Zoological Journal of the Linnean Society, 148: 223-235, London 2006.
