- Kingdom: Animalia
- Phylum: Annelida
- Class: Polychaeta
- Subclass: Errantia
- Order: Phyllodocida
- Family: Polynoidae
- Scientific name: Harmothoe extenuata
- Norwegian: -
In contrast to the similar L. squamatus and L. clava, H. extenuata has 15 pair of scales. on the back, rather than 12. Approximately ten of the last body segments are not covered by scales. The body length is usually 3-4 cm, but 7 cm has been recorded. It may easily be confused with other members of this family.
It can be found under rocks and crevices on any diveable depth.
Registered in the North Pacific and North Atlantic Ocean, as well as the in South Africa.