|
# of Described Species: First Appearance: Habitats: Marine (including intertidal), burrowers and epifaunal Shapes: Feeding Types: Filter-feeders |
|
| This important, entirely marine, group comprises many of the most familiar (and delicious) bivalves - the scallops (Pectinidae), oysters (Ostraeidae), pearl oysters (Pteriidae), mussels (Mytilidae) and arcs (Arcidae), as well about 18 other families. The hinge is taxodont (it has a few reduced teeth or is absent). A number of families have lost one of the adductor muscles (the monomyarian condition) and some have a nacreous shell interior. |
Many pterimorphs live as epifaunal animals being free-living, byssally
attached or cemented and have a reduced foot. The mussels seen on rocky shores in
great groups are an example of this type of lifestyle. Other pteriomorphs are shallow burrowers.
Scallops are interesting as some species have primitive "eyes" which allow them to sense light variation. They often combine this with the ability to quickly flee from predators using jets of water squirted from between their shells. |