Author: (Odhner, 1917)

Order: Nudibranchia  Family: Dendrodorididae

Maximum Size: 60 mm

Sightings: Sunshine Coast; Bali, Indonesia; Anilao, Philippines; Milne Bay, PNG

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Dendrodoris guttata (Odhner, 1917)

The dendrodorids are porostome nudibranchs lacking a radula, being suctorial feeders upon sponges, liquefying the sponge tissue before sucking it up.

Dendrodoris guttata is a plump, oval-shaped nudibranch with a smooth, high-rounded profile in the manner of many members of its genus. The foot is broad but still overhung by the mantle skirt that is thin and undulating. The background colour was originally described as a bright brick colour, but across the species population there is a wide variation from orange through to a quite pale brown. Large “roundish” spots cover the dorsum in an even distribution. The spots are of a darker shade to the general background colour each with a perimeter ring of an even darker shade. The background colour forms a light halo around each of the spots. The mantle margin carries evenly spaced spots, sometimes reaching the edge, that are of a darker colour than those on the rest of the dorsum. In some specimens these are of a purple hue. Rhinophores are lamellate, of a dark red or orange (rarely purple) often with white on the posterior face of the tip and black on the anterior face of the tip. The distal end of the anterior face tapers posteriorly. The tripinnate gill can spread widely across the posterior of the notum or contract completely into a pocket beneath the mantle surface. The gill rachides are red to dark brown to yellow in colour with the feathery pinnae usually a translucent white.

The pale yellow spawn is laid as a spiral ribbon of several whorls, on edge, upon the substrate with a wavy free edge. The large size of the individual eggs in the ribbon has led to conjecture that this species might have lecithotrophic development (Rudman, 2000).

Distribution ranges from Japan right down through the Indo-Pacific to the west and east coasts of Australia. The species type location is off the Western Australia coast at Cape Jaubert, south west of Broome. It is not commonly found, its presence fluctuating greatly from year to year.

An unusual colour form, with purple mantle margin spots and rhinophore tips has been recorded by Tracey Howley from the Mooloolah River, Sunshine Coast, Queensland at La Balsa Park and a series of images of that find are available to view in the gallery above.

Originally described as Doridopsis guttata.

David A. Mullins – October 2024

References:
– Odhner, N. H. (19l7). Results of Dr. E. Mjobergs Swedish scientific expeditions to Australia 1910-13, Pl. 17, Mollusca. Kungl. Svenska vetenskaps Akademiens Handlingar, 52(16): 1-115, Pls. 13.

Gosliner, T. & Behrens, D. (1997?). Week 77, Dendrodoris guttata at Mike Miller’s SlugSite: http://slugsite.us/bow/nudiwk77.html

– Rudman, W. B., (2000, June 12). Dendrodoris guttata (Odhner, 1917). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/dendgutt and associated messages.

– Gosliner, T. M., Valde ́s, A ́. & Behrens, D. W. (2018). Nudibranch & Sea Slug Identification – Indo-Pacific, 2nd Edition. New World Publications, Jacksonville, Florida, USA.