Alexander Semenov, Russland
Info
Onchidoris bilamellata (Linnaeus, 1761)
The species has a northern and arctic distribution area. It occurs on both sides of the North Atlantic and along the northern west coast of Alaska. In northern European waters it occurs from the Atlantic coast of France northwards to the British Isles, the Faroe Islands, Iceland, Greenland and the White Sea. It is also widespread on the Swedish west coast. Along the Norwegian coast it can be found along the entire coast from the Oslofjord north to Vardø.
Onchidoris bilamellata has a flat and oval body shape. The mantek is densely covered with numerous club-shaped tubercles of various sizes. They contain short lime needles. The species also has a hidden defense against predators, as it has glands in its mantle that can secrete sulfuric acid.
The rhinophores have up to 12 inclined lamellae that cover almost the entire rhinophore. The rhinophores can be partially retracted into separate pockets. The gill bush has up to 29 single-pinnate gills without branches. In the space between the anal papilla and the gill bush there are a few scattered tubercles.
The body color is dull white with a brown pattern on the mantle. The tubercles lack this brown pigmentation. The rhinophores are usually covered with brown pigmentation, while the gill bush is gray-brown to light brown. Some specimens can be almost completely white.
Onchidoris bilamellata lives exclusively on barnacles, both in the intertidal zone and in shallow water down towards the kelp forest. It feeds on several species of barnacles, such as the barnacle Semibalanus balanoides and the barnacle Balanus crenatus.
The species has an annual life cycle and reproduces in both spring and autumn. The white egg band is short and flattened and is laid on the ground in an arc or zigzag. The band stands at its edge and is often wider at the top than at the bottom, like a funnel. The egg mass can contain up to 125,000 eggs, 80–100 micrometers in diameter.
The genus name is complex, Doris is the name of a sea nymph in Greek mythology and Onkos comes from Greek and means tubercle. The name Onchidoris therefore refers to a Doris with vaginal tubercles.
The species name "bilamellata" comes from Latin and means "two plates" which probably refers to the shape of the gill bush.
Brown variants of Onchidoris bilamellata can resemble the brown individuals of Acanthodoris pilosa and cause confusion.
Synonyms:
Doris bilamellata Linnaeus, 1767
Doris fusca O. F. Müller, 1776
Lamellidoris bilamellata (Linnaeus, 1767)
Lamellidoris fusca (Muller, 1776)
Onchidoris fusca (Müller O. F., 1776)
Onchidoris leachii Blainville, 1816
The species has a northern and arctic distribution area. It occurs on both sides of the North Atlantic and along the northern west coast of Alaska. In northern European waters it occurs from the Atlantic coast of France northwards to the British Isles, the Faroe Islands, Iceland, Greenland and the White Sea. It is also widespread on the Swedish west coast. Along the Norwegian coast it can be found along the entire coast from the Oslofjord north to Vardø.
Onchidoris bilamellata has a flat and oval body shape. The mantek is densely covered with numerous club-shaped tubercles of various sizes. They contain short lime needles. The species also has a hidden defense against predators, as it has glands in its mantle that can secrete sulfuric acid.
The rhinophores have up to 12 inclined lamellae that cover almost the entire rhinophore. The rhinophores can be partially retracted into separate pockets. The gill bush has up to 29 single-pinnate gills without branches. In the space between the anal papilla and the gill bush there are a few scattered tubercles.
The body color is dull white with a brown pattern on the mantle. The tubercles lack this brown pigmentation. The rhinophores are usually covered with brown pigmentation, while the gill bush is gray-brown to light brown. Some specimens can be almost completely white.
Onchidoris bilamellata lives exclusively on barnacles, both in the intertidal zone and in shallow water down towards the kelp forest. It feeds on several species of barnacles, such as the barnacle Semibalanus balanoides and the barnacle Balanus crenatus.
The species has an annual life cycle and reproduces in both spring and autumn. The white egg band is short and flattened and is laid on the ground in an arc or zigzag. The band stands at its edge and is often wider at the top than at the bottom, like a funnel. The egg mass can contain up to 125,000 eggs, 80–100 micrometers in diameter.
The genus name is complex, Doris is the name of a sea nymph in Greek mythology and Onkos comes from Greek and means tubercle. The name Onchidoris therefore refers to a Doris with vaginal tubercles.
The species name "bilamellata" comes from Latin and means "two plates" which probably refers to the shape of the gill bush.
Brown variants of Onchidoris bilamellata can resemble the brown individuals of Acanthodoris pilosa and cause confusion.
Synonyms:
Doris bilamellata Linnaeus, 1767
Doris fusca O. F. Müller, 1776
Lamellidoris bilamellata (Linnaeus, 1767)
Lamellidoris fusca (Muller, 1776)
Onchidoris fusca (Müller O. F., 1776)
Onchidoris leachii Blainville, 1816
