Synsphyronus gigas is a species of pseudoscorpion in the Garypidae family. It is endemic to Australia. It was described in 1971 by Austrian arachnologist Max Beier.[1]
The body length of the male paratype is 4.5 mm; that of female specimens 5–6 mm. Colouration is dull reddish-brown, the male somewhat darker.
The species occurs in Western Australia in the Great Victoria Desert. The type locality is 18 km east of Milne Rock, where the pseudoscorpions were found beneath stones.[1]
The pseudoscorpions are terrestrial predators.[1]