Berthella ornata
(Cheeseman, 1878)

Order: NOTASPIDEA
Superfamily: PLEUROBRANCHOIDEA
Family: Pleurobranchidae

DISTRIBUTION

Endemic to New Zealand. Found throughout the three main islands and also the Chatham Ids, from the intertidal to the shallow sublittoral.

PHOTO

Locality: Under rocks, 10 cm, Whangaparaoa, Auckland, NZ, Pacific, 12 March 2009, Rock pool. Length: About 1 inch. Photographer: Graham Bould.

The mantle is a smooth translucent cream to light brown with large irregularly shaped dark brown patches scattered all over. The foot and oral veil are translucent clear. The rhinophores usually have some dark brown regions or patches, but the tips are always white.  Like all species of the genus, it has a small, flattened, lightly calcified, internal shell, hidden in the mantle tissue. When disturbed the animal can exude a milky white secretion either from a single spot or from the whole mantle. It is reported to grow to at least 70 mm in length. Willan (1984) report finding spicules from the sponge Plakina monolopha in faeces of  B. ornata.

  • Cheeseman, T. F. (1879) Descriptions of three new species of Opisthobranchiate Mollusca, from New Zealand. Proceedings of the Zoological Society of London, 1878: 275-277, Pl. 15
  • Willan, R. C. (1983) New Zealand side-gilled sea slugs (Opisthobranchia: Notaspidea: Pleurobranchidae). Malacologia, 23, 221-270.
  • Willan, R. C. (1984) A review of diets in the Notaspidea (Mollusca: Opisthobranchia). Journal of the Malacological Society of Australia, 6, 125-142.
Authorship details
Rudman, W.B., 2009 (March 16) Berthella ornata (Cheeseman, 1878). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/bertorna

Related messages


More on Berthella ornata

August 17, 2009
From: Graham Bould

Concerning message #22334:

Three photos of Berthella ornata attached. In the photo with 2 slugs a very small white commensal crab can be seen on the back of the larger slug. This was seen to emerge from under the mantle of the smaller slug.

Locality: Rocks, Low tide level, New Zealand, Pacific, 22 July 2009, Under stone in rock pool. Length: 80 mm. Photographer: Graham Bould.

Best wishes
Graham Bould

graham@grahambould.net

Bould, G., 2009 (Aug 17) More on Berthella ornata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22587

Dear Graham,

Thanks for some more photos of this New Zealand endemic species. In the close-up we can see traces of the 'bumps' which cover the surface of many pleurobranchs. In the case of many 'smooth' looking species such as this species, the 'bumps' are very reduced in size.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Aug 17). Comment on More on Berthella ornata by Graham Bould. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22587

Berthella ornata from near Auckland, NZ

March 17, 2009
From: Graham Bould

I found this slug under a rock north of Auckland yesterday. The top is smooth without any protuberances. It's about an inch long. Are you able to help in IDing it?

Locality: Under rocks, 10 cm, Whangaparaoa, Auckland, NZ, Pacific, 12 March 2009, Rock pool. Length: About 1 inch. Photographer: Graham Bould.

Thanks
Graham Bould

graham@grahambould.net

Bould, G., 2009 (Mar 17) Berthella ornata from near Auckland, NZ. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22334

Dear Graham,

Although there are no anatomical clues in your photo to what sort of slug it is, its colour makes me sure that it is the uncommon pleurobranch, Berthella ornata, which is known only from New Zealand waters. It is nice to be able to add it to the Forum.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Mar 17). Comment on Berthella ornata from near Auckland, NZ by Graham Bould. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22334