In future, P. formosensis might become a subspecies of P. hamptoni, or some snakes from the mainland might be classified as P.

[5] Further studies have shown that Pareas komaii is a valid species, instead of being a synonym of P. formosensis.

Female snakes produce a clutch of 2–9 eggs; the hatchlings measure about 15 cm (5.9 in) in total length.

[3] P. formosensis is readily distinguished from P. komaii and P. atayal by its red iris and totally smooth dorsal scales.

[5] The Formosa slug snake occurs throughout the mountain regions of Taiwan, except for the north-eastern tip of the island.