As with other members
of Family Polynoidae,
the dorsal side of this species is covered with a
series of platelike elytra. Harmothoe
imbricata has 15 pairs of elytra
which cover nearly all the segments (several elytra have fallen off the
individual above). The elytra
have a light fringe of papillae
around the edge (photo).
There is only one
basic kind of notoseta
and one kind of neuroseta
on any given segment. Most of the neurosetae
fork at the tip (are bifid).
thicker than the neurosetae.
One pair of eyes is visible dorsally (unless covered by elytra),
but the anterior pair of eyes cannot be seen except from the side (photo).
The lateral prostomial
antennae are inserted ventrally to the medial antenna (photo).
Color highly variable, though brown is common.
Common name(s): Fifteen-scaled worm, Free-living scaleworm
3 cm long. A few of the anterior elytra
have fallen off this
revealing the segments underneath. This individual was living
within the tube of another polychaete
in Fidalgo marina.
Cowles, July 2009)
How to Distinguish
Several other species of Harmothoe
have anterior eyes that are visible dorsally. Other Polynoids
have other numbers of elytra.
Range: A very widely distributed
species. Found throughout the northern hemisphere. Point
Alaska to s California on our coast.
Low intertidal to
Lives in a wide variety
of habitats: Freeliving intertidally under rocks and in
subtidally in kelp holdfasts or mussel beds. May live
with echinoderms or other polychaetes.
This scaleworm is very common in some parts of its range, such as
and SE Alaska. It is an active swimmer and can live in a wide
of salinities. The species is a predator which lies in wait,
pounces on its prey, using its large, jawed proboscis to subdue
Amphipods are common prey. It also eats some algae.
The pink eggs are released from the nephridiopores.
In some areas, females of this species brood their eggs under the elytra;
in other places they do not seem to do so. Brooding in our
takes place in summer. Larvae may have a long pelagic period
Polychaetes this species may live commensally with
robusta, and Diopatra
and Hanby, 2005
and O'Clair, 1998
General Notes and
abundances, unusual behaviors:
This oblique view of the head shows the posterior eyes, which are
dorsally, plus the anterior pair of eyes which are covered over by a
of the prostomium.
The two lateral prostomial
antennae are seen to be inserted ventral to the median
removed for this view.
with fine papillae,
especially along the posterior edges (to the right in this photo).
Authors and Editors of Page:
Dave Cowles (2009): Created original page
CSS coding for page developed by Jonathan Cowles (2007)