Goniobranchus leopardus can reach a maximum size of 6cm length. The body is elongate with a foot which is distinct from the upper body by a large skirt-like mantle hiding the foot. The top of the mantle is brownish with dark spots circled with white. The margin of the mantle is white with at the external border a fine purple to electric blue line. The rhinophores are lamellate and contractile, the base is white topped with blue to purple but they can also be white with a longitudinal blue to purple line. The branched gill has a whitish external side, the internal surface is golden.
References
↑Rudman W.B. (1987) The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris epicuria, C. aureopurpurea, C. annulata, C. coi and Risbecia tryoni colour groups. Zoological Journal of the Linnean Society 90: 305–407. page(s): 358
↑Beesley, P.L., Ross, G.J.B. & Wells, A., 1998. Mollusca – The southern synthesis, vol.5, CSIRO, ISBN0-643-05756-0
↑Debelius, H. & Kuiter, R.H. (2007) Nudibranchs of the world. ConchBooks, Frankfurt, 360 pp. ISBN978-3-939767-06-0 page(s): 141
↑Gosliner, T.M., Behrens, D.W. & Valdés, Á. (2008) Indo-Pacific Nudibranchs and seaslugs. A field guide to the world's most diverse fauna. Sea Challengers Natural History Books, Washington, 426 pp. page(s): 217