sentences:  Unlike poison dart frogs which merely secrete poison from their skin, this species is equipped with skull spines capable of injecting venom into other animals, or human hands, via headbutting, a tactic it shares with "Aparasphenodon brunoi".The skin secretions contain a number of low-molecular mass steroids and alkaloids.In the laboratory, these produce a powerful nociceptive (painful) effect and cause oedema in mice cells.