Synsphyronus spatiosus is a species of pseudoscorpion in the Garypidae family.

It was described in 2022 by Australian arachnologist Mark Harvey.

The specific epithet spatiosus (Latin: 'spacious' or 'large') refers to both the large size of the species and of the type locality.

[1] The species occurs in Western Australia on granite outcrops in the Murchison bioregion.

The type locality is Walga Rock, on Austin Downs station, where the pseudoscorpions were found beneath exfoliating granite slabs.