Chromodoris krohni
(Verany, 1846)

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae

DISTRIBUTION

Fairly common from northern Spain to North Africa and the Mediterranean Sea.

PHOTO

Bay of Algeciras (Strait of Gibraltar, Southern Spain). UPPER RIGHT: Size: 22 mm., Depth: 23m., Date: October, 1999. LOWER LEFT: Size: 13 mm., Depth: 19 m., Date: January, 1999. LOWER RIGHT: Size: 22 mm., Depth: 23m., Date: October, 1999. PHOTOS: Alma Sánchez

Chromodoris krohni (Vérany, 1846) is fairly common from northern Spain to North Africa and the Mediterranean Sea. It is clearly distinguishable from other chromodorid species from the eastern Atlantic by the presence of three yellow lines on a pale blue background. The lines run from the gill area to the rhinophores, the two most external joining right behind the gill. In the adult specimens there are also small yellow dots next to the lines (Upper & Lower Right photos). In the juvenile specimens the lines are pale yellow or even white (Lower Left). Other eastern Atlantic species with yellow of white lines have a dark blue dorsal color and they belong to the genus Hypselodoris (H. tricolor, H. villafranca, H. bilineata, H. cantabrica, H. malacitana, H. picta, H. fontandraui and H. orsini. They are easily distinguishable from C. krohni by the narrower mantle margin and absence of mantle glands in large areas of the mantle edge. A probably related species to C. krohni is Chromodoris purpurea (Risso in Guérin, 1831), which is very similar but lacks yellow lines. Because of the pale blue background color this species was not included in the monograph by Ortea et al. (1996) dealing with the dark blue Atlantic chromodorids.
Angel Valdes

Reference:
• Ortea, J., Valdés, Á. & García-Gómez, J.C. (1996) Revisión de las especies atlánticas de la familia Chromodorididae (Mollusca: Nudibranchia) de grupo cromático azul. [Review of the Atlantic species of the family Chromodorididae (Mollusca: Nudibranchia) of the blue chromatic group.] Avicennia. Revista de Ecologia y Oceanologia y Biodiversidad Tropical. Supplement 1. 165pp.
• Schmekel, L. & Portmann, A. (1982) Opisthobranchia des Mittelmeeres. Springer-Verlag: Berlin. 410pp.

Authorship details
Valdes, A., 2001 (January 21) Chromodoris krohni (Verany, 1846). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/chrokroh

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