How to recognize an Isias female:

Using a binocular :

Prosome oval.

4 visible thoracic segments.

Urosome almost symmetrical with 3 segments.

P5 quite symmetrical, biramous, with size similar to other legs.

Furca quite long (about 1/3 of urosome lenght).

Using a microscope :

P5 exopodite 3-segmented, P5 endopodite 1-segmented

The second segment of the P5 exopodite have a strong inner marginal spine.

How to differenciate I. clavipes from other Isias

Using a binocular :

Corners of the last thoracic segment rounded.

A1 not much longer than the prosome.

Genital segment with 2 strong spines on the ventral side.

Using a microscope :

P5 basipodite with a strong spine perpendicular to P5 plane.

 

Ecological Notes :

Neritic species. There is no other Isias species reported in mediterranean waters.