Goniobranchus tinctorius (Rüppell & Leuckart, 1830)

Description

Reaches about 50 mm in length. Ground colour milky white, the dorsum marked with a network of fine blood-red veins together with rows of similarly coloured dots concentrated on the central convexity. The mantle margin bears a sulphur-yellow border, and the upper surface of the foot shows irregular red blotches. About nineteen pyramidal pinnate gills, fully retractable beneath the mantle.

Distribution

Type locality is El-Tor on the southern Sinai Peninsula, Red Sea. Restricted to the Red Sea and the Sea of Oman.

Etymology

The specific epithet tinctorius is the Latin "of dyers" (from tingere, "to dye"). The original authors noted that this species stained the preserving alcohol brown-black even after ten successive changes of the medium, a striking dye-secreting property reflected in the name.

Remarks

The name was long applied broadly across the Indo-West Pacific, including to the Japanese species known as サラサウミウシ. Recent molecular work has restricted Goniobranchus tinctorius sensu stricto to the Red Sea and adjacent Sea of Oman, while the red-reticulate Pacific populations are now recognised as a separate species complex.

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References

• Doris tinctoria, Rüppell E. & Leuckart F.S. (1828-1830). Atlas zu der Reise im nördlichen Afrika von Eduard Rüppell. Erste Abtheilung. Zoologie, Neue wirbellose Thiere des Rothen Meers. Frankfurt am Main: H.L. Brönner. iv + 47 pp., 12 pls.
• Goniobranchus tinctorius, 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 tinctorius (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