Author: (Rudman, 1990)

Order: Nudibranchia  Family: Chromodorididae

Maximum Size: 40 mm

Sightings: Sunshine Coast

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Ardeadoris electra (Rudman, 1990)

Another species having a broad white mantle with an undulating edge carrying a yellow/orange band to the margin.

Ardeadoris electra is a medium-sized dorid nudibranch reported up to 40 mm in length. The shape of the mantle is oval and overhangs the foot. The mantle edge has series of folds with a particularly large distinctive fold both sides midway along the length. The edge of the mantle lacks the thick “puffy” look of Ardeadoris averni and Ardeadoris rubroannulata. The tail of the foot is visible where it extends past the posterior edge of the mantle. The rhinophores can retract into protective pockets. The gills too can retract into a protective pocket. The gill is relatively sparse but still arranged in an arc around the anus, open posteriorly, with each end of the arc forming an inward spiral. Each gill is more inflated than those of Ardeadoris egretta. The gills move continuously with a regular rhythmical motion when expanded.

The mantle colour is a semi-translucent white to cream with a yellow-orange band on the margin both dorsally and ventrally. There is also a broad sub-marginal band of vivid opaque white that contain small underlying mantle glands, according to Rudman. The translucent white foot/tail carries a narrow band of opaque white on the margin but any other colour is absent. Each oral tentacle (usually not visible) carries a dorsal yellow patch on the tip. The rhinophore clubs are orange/brown and bear broad white lines up both the anterior and posterior faces. The colour of the clubs tapers off to translucent white stalks. The gills have translucent white sides (lamella) and orange-brown inner and outer faces.

Ardeadoris electra is a spongivore, but the type of sponge preyed upon has not been identified/recorded.

Distribution is broadly the western Pacific, from the Philippines, Malaysia, Indonesia, PNG, Solomon Islands, New Caledonia, the GBR to southern Queensland, Australia. Yonow, 2008 lists this species from the Red Sea.

Originally described as: Glossodoris electra.

Later, in a wide ranging molecular sequencing of the Chromodorididae family in 2012 (Johnson & Gosliner), it was shifted to Ardeadoris, (by hypothesis), a genus raised by Rudman in 1984. It joined Ardeadoris egretta (Rudman’s type species for the genus) and Ardeadoris scottjohnsoni, but going across with it were ten other species all from the Glossodoris genus (and one from Noumea). This group of ten were known by taxonomists to be similar in some respects but at the same time to be varying in certain aspects from the other Glossodoris making them difficult to place definitively. This was resolved by that molecular sequencing. There are a number of species in the Chromodorididae family, and across several genera, that have a substantially white mantle trimmed with a yellow/orange line to the mantle margin or sub-margin. Nearly all of the current thirteen Ardeadoris species fall into that general description.

Regarding the naming of this species, Rudman advises: “The name ‘electra’ is a reference to Chelidonura electra Rudman, 1970, a beautiful white aglajid opisthobranch with a bright yellow border, which has been found on both expeditions in which Glossodoris electra sp. nov. has been collected.”

David A. Mullins – February 2022

References:
– Rudman, W. B, (1990.) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: further species of Glossodoris, Thorunna and the Chromodoris aureomarginata colour group. Zoological Journal of the Linnean Society, 100(3): 263-326.

– Rudman, W. B., (November 8,1999). Glossodoris electra Rudman, 1990. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/gloselec

– Debelius, H. & Kuiter, R. H., (2007). Nudibranchs of the World. IKAN-Unterwasserarchiv, Frankfurt.

– Yonow, N. (2008). Sea Slugs of the Red Sea. Pensoft Publishers.

– Coleman, N., (2008). Nudibranchs Encyclopedia. Neville Coleman’s Underwater Geographic Pty Ltd, Springwood, Qld.

– Johnson, R. F. & Gosliner, T. M., (2012). Traditional taxonomic groupings mask evolutionary history: A molecular phylogeny and new classification of the chromodorid nudibranchs. PLoS One 7 (4): e33479.

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