Onchidoris bilamellata
| Onchidoris bilamellata | |
|---|---|
 |
|
| A live individual of Onchidoris bilamellata, head end towards the right | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): |
clade Heterobranchia clade Euthyneura |
| Superfamily: | Onchidoridoidea |
| Family: | Onchidorididae |
| Genus: | Onchidoris |
| Species: | O. bilamellata |
| Binomial name | |
|
Onchidoris bilamellata (Linnaeus, 1767) |
|
| Synonyms | |
|
|
clade Euthyneura
clade Nudipleura
clade Nudibranchia
clade Euctenidiacea
clade Doridacea
Onchidoris bilamellata, common name the rough-mantled doris, is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Onchidorididae.
This nudibranch has a wide distribution, mostly in colder intertidal waters to a depth of about 20 m. It has been found in the North Atlantic and the North Sea from Britain and France to the Norwegian Sea, Iceland and Greenland; along the North American coast as far south as Connecticut. It has also been recorded in the North Pacific in the Bering Sea, and from Alaska south to northern California.
These sea slugs sometimes occur in abundant numbers during breeding time, swarming with over 1,000 individuals per square metre, as has been observed on numerous occasions. These swarms are all oriented in the same direction, determined by the flow of the tide. They follow each other at the same speed, forming columns, in different close-knitted rows.
This is a small species, no longer than 4 cm. They mostly show an abundant rusty brown pigment. But some individuals display a mixed pattern of colours, from a lighter brown colour to dark brown. Even fewer individuals are white, with brown color only in the rhinophores and the gills. A rare few are completely white, and yet they are not albinos, as their eyes are pigmented.
...
Wikipedia