How to recognize a Ctenocalanus female:

Using a binocular :

The prosome shape is almost perfectly ovoid.

Only 3 thoracic segments are visible (prosome 4-segmented).

A1 slightly longer than boby.

The rostrum is short.

P5 very small.

Urosome 4-segmented with a regular cylindrical shape.

Furca short.

Using a microscope :

The rostrum consists of 2 slender filaments

Outer spines on third exopod of P3 and P4 with cristate inner margin

P5 asymmetrical, consisting of 2-4 segments on the left side only

How to differenciate C. vanus from other Ctenocalanus

Using a microscope :

The genital segment and the genital pore in lateral view have specific shapes (see figures).

Ecological Notes :

Common epi- and bathypelagic species