Source citing this article: "The presynaptic neuromuscular blocking effect and phospholipase A2 activity of textilotoxin, a potent toxin isolated from the venom of the Australian brown snake, Pseudonaja textilis"
Toxicon, Volume 21, Issue 1, 1983, Pages 143-151
M.J. Su, A.R. Coulter, S.K. Sutherland, C.C. Chang. We don't have the paper, but we assume, that the reported LD50 value refers NOT to crude venom, but to textilotoxin instead. If anybody has the paper, please send it to us!