Medical Definition of ARTHRODESIS. : the surgical immobilization of a joint so that the bones grow solidly together: artificial ankylosis. the surgical immobilization of a joint so that the bones grow solidly together. ADVERTISEMENT.
Trapdoor spiders are not particularly harmful to man however, like Tarantulas, the tiny hairs on the legs of some species leave tiny red marks where the toothed hairs on the spiders' feet have clung to the skin. Mouse spiders are also a type of Trapdoor spider with huge chelicerae and may measure up to 35mm in body length.
Poison dart frogs. Poison dart frogs are so named because their poisonous secretions have been used by Amerindian tribes to poison blow darts for hunting. Only three species are dangerous to humans. One of those-the golden poison frog-is considered the most toxic vertebrate on Earth.oison dart frogs are so named because their poisonous secretions have been used by Amerindian tribes to poison blow darts for hunting. Only three species are dangerous to humans. One of those-the golden poison frog-is considered the most toxic vertebrate on Earth.