Sunday, 6 March 2011


This large (4cm) scaleworm is probably a specimen of the species Harmothoe imbricata, although to identify thes creatures correctly it is necessary to use a hand lens and to examine the scales (elytra) in some detail.

Scaleworms are relatively common at Sandsend, Robin Hood's Bay and Kettleness etc. They cling to the underside of stones and can be easily missed. These photos were taken with the worms immersed in water, but when they're out of the water their colouration allows them to blend into the surface.

Harmothoe imbricata showing the two characteristic rows of fifteen scales (elytra), although the hindmost elytra on the right side is missing.
This second worm is probably another example of Harmothoe imbricata. At 2cm its much smaller and sports a completely different colour scheme. It has a rich chestnut coloured band down the centre and a white edge to each scale. Although it looks like poor camoflage, actually against corraline seaweeds and lichen, the pattern works well.
? Harmothoe imbricata wearing an alternative colour scheme

Breeding on our coast occurs during March and April. The females spawn twice during these months. Sperm are released onto the eggs which are held under the female's scales where early development takes place. Scaleworms can live for around four years.

Both were found at Sandsend on 25:02:11.

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