Goniobranchus alderi (Collingwood, 1881)

Description

A chromodorid reaching about 5 cm (the original description gives "2 inches"). The mantle is capacious, squarish in front and slightly emarginate, and completely covers the head. The body colour is an opaque yellowish white or cream, with a bright orange border running all around the edge of the mantle and the projecting portion of the foot. The dorsum is beautifully marbled with reddish brown, and an irregular row of carmine spots lies between the marbled area and the orange marginal band. The rhinophores are very small, set on short stalks, finely laminated and crimson alternating with white, with the commissure anterior. The gill plume consists of about ten simple four-sided angular leaflets, some bifurcating near the apex, arranged in an imperfect circle that curves outwards around the anal opening; the gills are reddish with crimson angles. The head bears two small white oral tentacles, and the foot is somewhat tubular posteriorly, extending about an inch beyond the mantle. The undersurface is a delicate translucent white.

Distribution

Type locality: Ke-lung Harbour (Keelung), northern Taiwan (Formosa). No further localities were given in the original description.

Etymology

The specific epithet alderi honours the British naturalist Joshua Alder (1792–1867), best known for the monograph of British nudibranchs that he co-authored with Albany Hancock.

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References

• Doris alderi n. sp., Collingwood C. (1881). II. On some New Species of Nudibranchiate Mollusca from the Eastern Seas. Transactions of the Linnean Society of London. 2nd Series: Zoology. 2(2): 123-140. https://doi.org/10.1111/j.1096-3642.1881.tb00300.x
• Goniobranchus alderi, 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.
• Goniobranchus alderi (red-reticulate complex), Soong G.Y., Wilson N.G. & Reimer J.D. (2020). A species complex within the red-reticulate Goniobranchus Pease, 1866 (Nudibranchia: Doridina: Chromodorididae). Marine Biodiversity. 50: 25. https://doi.org/10.1007/s12526-020-01048-w