Tyrinna nobilis
Bergh, 1898

Order: NUDIBRANCHIA
Suborder: DORIDINA
Family: Chromodorididae

DISTRIBUTION

Known from northern Chile to the sthn tip of Sth America and up the Atlantic coast as far as Valdes, Argentina. Reported here from Tristan da Cunha in the Sth Atlantic.

PHOTO

Locality: The animal photographed is from intertidal pools east of Harbour, Tristan da Cunha, Intertidal and shallow subtidal to 30m, British Overseas Territory, South Atlantic Ocean, 2004-2007. Extremely exposed rocky coasts, shallow subtidal. 37 03' 50.94"S, 12 18' 43.64"W (position derived from Google Earth; note decimal seconds). Photographer: Sue Scott.

The animal is translucent white with an opaque white line around the edge of the mantle and the foot. The simple gills are also edged in white as are each rhinophore stalk and club. There are three irregular lines of or orange red spots around the mantle edge, the outermost consisting of many small spots, the middle line containing slightly larger spots and the innermost a few much larger spots. Each spot overlies an opaque white mantle gland, and there are further mantle glands which are not coverd by orange pigmentation. The central region of the mantle, between the gills and the rhinophores lacks orange spots. It is reported to grow to approximately 50 mm in length.

The main difference between T. nobilis and T. evelinae would appear to be that in the latter the orange spots are scattered all over the mantle, and if there are larger spots they are usually concentrated around the mantle edge. Where T. nobilis is found in the cold waters of the southern part of Sth America, T. evelinae replaces it in the warmer north from Mexico to Peru on the Pacific coast, and from the Caribbean to sthn Brazil on the Atlantic coast. It has also been reported from west Africa.

Chromodoris juvenca Bergh, 1898, Tyrinna pusae Marcus, 1959 are considered to be junior synonyms of this species, and Schroedl & Millen (2001) although considering Doris delicata Abraham, 1877 to be the earliest name, have invoked a section of the new Code to disregard the name.

• Muniain, C., A. Valdés, et al. (1996). Redescription of Tyrinna nobilis Bergh,1898 (Opisthobranchia: Chromodorididae) from Patagonia, Argentina. Journal of Molluscan Studies 62: 265-273.
• Schroedl, M. and S. V. Millen (2001). Revision of the nudibranch gastropod genus Tyrinna Bergh, 1898 (Doridoidea: Chromodorididae). Journal of Natural History 35(8): 1143-1171.
• Valdés, A. and C. M. L. Afonso (2003). Synonymy of Cadlina burnayi Ortea, 1988, from the Cape Verde Islands (Opisthobranchia: Chromodorididae) with Tyrinna evelinae (Marcus, 1958). The Veliger 46(2): 176-179.

Authorship details
Rudman, W.B., 2009 (November 18) Tyrinna nobilis Bergh, 1898. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/tyrinobi

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