what is the most deadly spider
Phoneutria are poisonous to humans, and they are considered to be the deadliest of all the world’s spiders. Their venom is toxic to the nervous system, causing symptoms such as salivation, irregular heartbeat, and prolonged, painful erections (priapism) in men.
The Guinness Book of World Records instead recognizes the Brazilian wandering spider (Phoneutria) as the most venomous spider — just 0.006 mg of the venom can kill a mouse, according to the records. (A 2002 study notes that the LD50 of a female Phoneutria nigriventer with an egg sac is 0.63 mg/kg).