Tetrodotoxin identified in polyclad flatworms of temperate Eastern Australia

Soft bodied marine invertebrates often possess bioactive secondary metabolites that they utilise in defensive or offensive contexts. These invertebrates utilise toxic secondary metabolites as chemical defenses and as venoms to enable them to become successful in their environments. The field of marine natural products often studies molecules isolated from invertebrates and one largely overlooked, yet prevalent group are flatworms of the order Polycladida. The potent neurotoxin tetrodotoxin is known to occur within this group in species of the suborder Acotylea, although its occurrence is only documented in polyclads from Asia and New Zealand. Herein, this thesis firstly reviews what is known about natural products isolated from polyclads from both Acotylea and Cotylea. Then, Australian polyclads from both Acotylea and Cotylea are tested for tetrodotoxin, to expand knowledge of this molecules distribution throughout the order. Finally, these results are discussed and future directions for study are given.