They are mollusks protected by two lateral shells or "valves" that can close them using adductor muscles, with an elastic hinge called "hinge".
The shells are made of calcium carbonate.
They are invertebrates, aquatic, filter feeders and gill respirators.
Some marine species are well known and used for human consumption, such as mussels and cockles.
They do not have tentacles, radula, or eyes, although some species have sensitive organs.
The pallial cavity is large and contains the gills.
The foot is developed and is used to dig in sand, mud and even rocks.
Some species can make pearls spontaneously or induced.
They are always aquatic and there are about 10,000 species.
Scallops can move by quickly opening and closing the two valves.
The pendentives, scallops or scallops have light-sensitive organs or brightly colored "eyes" along their mantle.
Some oysters may contain pearls. When a grain of sand enters the shell and irritates the mantle, it surrounds it and later secretes thin layers of nacre that insulate it, finally forming the pearl.
Most bivalves are sand or mud burrowers, and some species are highly specialized drillers, even in rocks.
The dimensions vary from 2 mm of some freshwater species to the giant Tridacnas, more than 1 m and weighing more than 200 kg.
There are a large number of highly appreciated edible species, such as clams, mussels, cockles, razor clams, oysters, scallops, etc.
Typical bivalve species
- Malleus or Hammer (18 cm).
- Nacra pinna (35 cm).
- Zebra ark (7 cm).
- Pearl oyster (up to 18 cm).
- Scabra file (10 cm).
- echinas, scallops (up to 20 cm).
- Spondylus (12-20 cm).
- Mussel (7 cm).
- Tridacna "Holy water font" (up to 1.20 m).
- Cockles (5-10 cm).
- Tellinas (5-7 cm).
- Plakes (5-18 cm).
- Clams, clams (5-7 cm).
- Corculum (7 cm).
- Coquinas (1.5 cm).
- Tarazza auger (up to 60 cm).
- Mya arenaria (10 cm).
In Aragon the most typical mollusks of this class are the so-called naiads or freshwater clams.
The name naiads is used in honor of the mythical nymphs, protective beings of rivers and streams, who guarded the water currents, their way of life filtering and purifying the waters, and therefore causing a benefit to those who later uses them, makes them worthy of this name.
Image of a live specimen of Margaritifera auricularia from the Tauste Channel.
© Photo: Ramón M. Álvarez Halcón Archive (2001).
Many mollusks are excavators, but their job is very simple, and consists of inserting the animal into the mud or stones at the bottom, to hide from its enemies.
The body of all mollusks that have this habit is more or less elongated, so that they can reach the water for food purposes while the shell remains buried.
Species of bivalve mollusks found in the Imperial Canal of Aragon as it passes through Zaragoza:
- Margaritifera auricularia (there are records from the beginning of the 20th century, but it is no longer found in Zaragoza capital).
- Unio elongatulus
- Potomida littoralis
- Anodonta cygnea
- Pisidium casertanum
- Pisidium personatum
- Pisidium henslowanum
According to Ramón M. Álbarez-Halcón.
Other information about Molluscs
- Introduction
- Monoplacophores
- Poliplacophores
- Scaphopods
- Gastropods
- Bivalves or lamelibranchs
- Cephalopods
Other information about fauna in Aragón:
A small list of species in Aragon would be the following:
| Vertebrates | Invertebrates |
|---|---|
MammalsBirdsReptilesAmphibiansFishes |
MetazoansProtozoa |
|
images about the fauna in Aragon. photographs on invertebrates. beneficial animals for agriculture. | |
Also Aragon enjoys a diverse and varied Nature where passing by plants, animals, Geology, or landscapes we can arrive at a fantastic bestiary that lives in its monuments.
The information will not be complete without a stroll by its three provinces, with shutdown in some of its spectacular landscapes like Ordesa, the Moncayo, Monegros or by opposition the Ebro.
Also you can dedicarte to the intangible ones: from the legend compilation that also does to universal Aragon.