Synsphyronus tenuis is a species of pseudoscorpion in the Garypidae family. It is endemic to Australia. It was described in 2022 by Australian arachnologist Mark Harvey. The specific epithet tenuis (Latin: 'thin') refers to the species’ extremely slender appendages.[1]
Body lengths of males are 3.44–3.74 mm; those of females 3.66–4.29 mm. Colouration is generally yellowish-brown.
The species occurs in south-west Western Australia in the Geraldton Sandplains bioregion. The type locality is Kalbarri National Park, where the pseudoscorpions were found beneath sandstone rocks.[1]
The pseudoscorpions are terrestrial predators.[1]