The Platypus is also poisonous. "The male has a spur on the inner side of each hind limb, which is connected by means of a hollow groove to a poison gland. This spur is used to inflict wounds on natural enemies and other males, and may possibly play some part in mating. The poison is capable of inflicting a very painful injury to humans."
http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/BHAN-53573T?open