UPPER PHOTOS: From Figure 16. Rostanga bassia, radular morphology, Flinders, Victoria, AM C149516A. A, Innermost left lateral teeth; E, outer right lateral teeth. A, scale bar = 30 µm; E = 100 µm.
LOWER PHOTOS: From Figure 17. AM C149516B. D, transition zone on right side; E, outermost lateral teeth. Scale bar = 30 µm in both cases. Photos: G. J. Avern. [Rudman, W.B. & Avern, G.J. (1989). The genus Rostanga Bergh, 1879 (Nudibranchia:
Dorididae) in the Indo-West Pacific. Zoological Journal of the Linnean Society 96: 281-338.]
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The innermost lateral teeth have a broad basal plate and a recurved triangular blade with a fringe of approximately 30 long bluntly rounded denticles along the whole of the inside edge (Figs A). The inner lateral teeth from Tooth 2 are similar in size to Tooth 1 but are simple non-denticulate hooks. The teeth slightly increase in size from Tooth 2 to approximately Tooth 14 where there is a transition zone with a quadrupling in length over four or five teeth. In this transition zone a relatively short outer denticle appears some distance down from the tip of the tooth (Figs D). In the outer lateral teeth, from approximately Tooth 20, three or four rod-like denticles, usually attached to a common base, are present in the fork between the outer denticle and the cusp. The rod-like denticles grade in length, the shortest, slightly longer than the outer denticle, is adjacent to it, and the longest is adjacent to the cusp. In this species the cusp remains considerably longer than the rod-like denticles (Figs 16E, 17E). The jaw plates are large with many long tightly packed chitinous rodlets. They are not as clearly arranged in rows as in R. arbutus and R. calumus.
The radular formulae of two specimens from Victoria are:
52.0.52 x 53 (+ 1) - 23 mm alive (AM C149516)
51.0.51 x 51 (+ 2) - 22 mm alive (AM C149516)
Rudman, W.B., 2002 (February 5) Rostanga bassia - Radula. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/rostbassrad