species: Thuridilla gracilis in Lizard Island area: all known taxa (Lizard Island Field Guide)
Thuridilla gracilis

©Barbara Banks: Thuridilla gracilis at Lizard Island

©Barbara Banks: Thuridilla gracilis at Yonge Reef near Lizard Island.

©Lyle Vail: Thuridilla gracilis at Pidgin Point, Lizard Island.
Kingdom Animalia
Phylum Mollusca
Class Gastropoda
Order Sacoglossa
Family Plakobranchidae
Genus Thuridilla
Species Thuridilla gracilis



Distinguishing features

Variable colouration involving a dark base colour, often green or black, with narrow longitudinal lines that may be white, reddish or blueish, that sometimes widen to make a string-of-beads pattern.


  • Up to 2.5 cm (Humann and Deloach, 2010)



©Atlas of Living Australia: Australian distribution

Web resources


References that assist with identification

  • Humann, P. and N. Deloach (2010). Reef Creature Identification: Tropical Pacific New World Publications Inc., Jacksonville, Florida, USA.

Other references

  • Christa., G., K. Händeler, P. Kück, M. Vleugels, J. Franken, D. Karmeinski and H. Wägele (2015). Phylogenetic evidence for multiple independent origins of functional kleptoplasty in Sacoglossa (Heterobranchia, Gastropoda), Organisms, Diversity and Evolution, 15: 23-26. LIRS catalog number 1870.
  • Christa, G., K. Haendeler, T.F. Schaberle, G.M. Konig and H. Wagele (2014). Identification of sequestered chloroplasts in photosynthetic and non-photosynthetic sacoglossan sea slugs (Mollusca, Gastropoda), Frontiers in Zoology, 11. LIRS catalog number 1785.
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