In the classical accounts, the salamander was great lizard whose bite was exceedingly poisonous. People believed that it lived in volcanoes or could be found in the hottest part of the fire. Salamander was thought to poison fruit trees, according to medieval bestiaries. In an Anglo-Saxon bestiary, the salamander is said to stop mouths of lions as an illustration of how the faithful will be freed from the fires of judgement.
John and Caitlin Matthews, The Element Encyclopaedia of Magical Creatures, 2013, Salamander, p 402