Pholadomyoida
| Pholadomyoida | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Pholadomyoida | ||||||||||||
| Newell , 1965 |
The Pholadomyoida are an order of the mussels (Bivalvia), which belongs to the superordinate order Anomalodesmata within the subclass Autolamellibranchiata . The oldest representatives of this group are known from the Ordovician .
Characteristics
The original groups of the order are characterized by housings with mostly identical keys; housing with more or less pronounced inequality often occurs in the younger groups. Smaller groups even have "shell-atypical" tubular housings. The shell is aragonitic with pearlescent prismatic microstructures. The lock is largely reduced; there is rarely a cardinal and a lateral tooth. The ligament is located externally, semi-internally or internally on a lithodesma or chondrophor . There are even forms that have completely reduced the ligament. Most forms have approximately the same size sphincter muscles ("isomyar"), few groups have anisomyar sphincters.
Way of life
The representatives of the order Pholadomyoida have developed a wide range of different habitats in the sea, ranging from the tidal areas to the deep sea. There are shallow to deeply digging forms in the soft sediment, forms drilling into the hard substrate or forms attached to the hard substrate.
Systematics
The order contains the following recent superfamilies:
- Superfamily Pholadomyoidea King, 1844
- Superfamily Pandoroidea Rafinesque, 1815
- Superfamily Clavagelloidea d´Orbigny, 1844
as well as the two extinct superfamilies:
- Superfamily † Ceratomyoidea Arkell, 1934
- Superfamily † Sinodoroidea Pojeta & Zhang, 1984
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.