Synonyms & Common name
Elysia bayeri Er. Marcus, 1965; Elysia ratna Er. Marcus, 1965; Thuridilla ratna Er. Marcus, 1965; Thuridilla gracilis Risbec, 1928. Thuridilla bayeri often known as sap sucking slug or painted slug.
 
Anatomically there are differences between the size of pharyngeal pouch (figure 1) and radula teeth of T. bayeri and T. ratna (figure 2). The size of egg capsules may reflect the different development patterns. T. bayeri and T. ratna egg size is similar, but capsules of T.bayeri is smaller, and probably has planktotropic development. T. ratna egg is larger, therefore, the development of this species could possibly be lecithotrophic (Jensen 1992).
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| Figure 1: Camera lucida drawings, modified from Jensen (1992), of the pharynx of Thuridilla ratna (1) and Thuridilla bayeri (2). Dorsal view (a), ventral view (b), and ventral view (c). Abbreviations: longtidutial ascus-muscle (am), buccal ganglion (bg), pharyngeal pouch (pp), dorsal septate muscle (sam). |
Figure 2: Scanning Electron Microscope (SEM) photos of radular teeth of Thuridilla bayeri (A), and Thuridilla ratna (B) modified from Jensen 1992. Size: T.bayeri = 50-65μm, T. ratna = 40-55μm
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