Sylvain Le Bris, Frankreich
Info
Aplidium fuscum is a colonial, microphagous sea squirt that can be observed in the sea in numerous small round cushions or in a single large flat cushion colony and is mainly distributed in the Mediterranean Sea.
However, there are also two reports of findings in the Indian Ocean, one from the Kerguelen Archipelago, a group of islands in French Southern and Antarctic Territories, and one from the Nicobar Islands in the Bay of Bengal.
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This sea squirt occurs in various shades of color, ranging from the color of milk coffee (hazelnut) to chocolate.
The common tunic is embedded with fine sand, especially at the base.
Aplidium fuscum is sometimes marked with white dots or small white areas along the zoooid rows, as well as pigmented inclusions.
To rule out possible confusion, the sea squirt can take on a reddish color when removed from its location.
The surface of the cushions is crisscrossed by clearly visible cloacal channels, which are visible in active filtering colonies.
These channels open into one or a few outflow siphons (cloaca), which resemble small chimneys.
The zooids are arranged in parallel lines or circles around the outflow siphons; the mouth and cloacal siphons and the channels are only visible in expanded animals, while retracted colonies take on a smooth, resinous appearance.
Its characteristic hazelnut color makes it unlikely to confuse Aplidium fuscum with other colonial sea squirts that also occur in cushion form.
Sea squirts generate a water current (which enters through the small inflow openings) by moving the cilia of the pharynx to capture edible microparticles. This self-generated current also serves to exchange gases in the sea squirt.
Non-digestible particles, which unfortunately increasingly include man-made microplastics, leave the sea squirt through the outflow siphon.
Reproduction:
The gonads are located in the long postabdomen, the testes are aligned, and the ovary is located relatively deep.
There is only one embryo per zooid, which is incubated in the cloacal cavity. This “monobrut” probably also explains the local distribution of the species, although strong currents can also cause the embryos to drift somewhat.
After the larvae are released into the sea, they swim around freely for a very short time until they finally settle in a suitable location.
The zooids are elongated and relatively large, reaching an average length of 1.5 cm.
The abdomen is about the same size as the thorax, and the cylindrical stomach has six longitudinal ribs.
Synonym: Amaroucium fuscum Drasche, 1883 · unaccepted (original combination)
However, there are also two reports of findings in the Indian Ocean, one from the Kerguelen Archipelago, a group of islands in French Southern and Antarctic Territories, and one from the Nicobar Islands in the Bay of Bengal.
.
This sea squirt occurs in various shades of color, ranging from the color of milk coffee (hazelnut) to chocolate.
The common tunic is embedded with fine sand, especially at the base.
Aplidium fuscum is sometimes marked with white dots or small white areas along the zoooid rows, as well as pigmented inclusions.
To rule out possible confusion, the sea squirt can take on a reddish color when removed from its location.
The surface of the cushions is crisscrossed by clearly visible cloacal channels, which are visible in active filtering colonies.
These channels open into one or a few outflow siphons (cloaca), which resemble small chimneys.
The zooids are arranged in parallel lines or circles around the outflow siphons; the mouth and cloacal siphons and the channels are only visible in expanded animals, while retracted colonies take on a smooth, resinous appearance.
Its characteristic hazelnut color makes it unlikely to confuse Aplidium fuscum with other colonial sea squirts that also occur in cushion form.
Sea squirts generate a water current (which enters through the small inflow openings) by moving the cilia of the pharynx to capture edible microparticles. This self-generated current also serves to exchange gases in the sea squirt.
Non-digestible particles, which unfortunately increasingly include man-made microplastics, leave the sea squirt through the outflow siphon.
Reproduction:
The gonads are located in the long postabdomen, the testes are aligned, and the ovary is located relatively deep.
There is only one embryo per zooid, which is incubated in the cloacal cavity. This “monobrut” probably also explains the local distribution of the species, although strong currents can also cause the embryos to drift somewhat.
After the larvae are released into the sea, they swim around freely for a very short time until they finally settle in a suitable location.
The zooids are elongated and relatively large, reaching an average length of 1.5 cm.
The abdomen is about the same size as the thorax, and the cylindrical stomach has six longitudinal ribs.
Synonym: Amaroucium fuscum Drasche, 1883 · unaccepted (original combination)
