The species was described in 1838 by John Edward Gray, based on a specimen held at the British Museum of Natural History, the author assigning it to the genus Tiliqua.

Their body is moderately stocky in form, with smooth scales, functional and strong limbs that each have five digits.

[5] The coloration of A. trilineatus resembles the species Pseudemoia entrecasteauxii, the southern grass-skink, which occurs in a similar distribution range.

[6] It is found in damp and cool habitat, such as wetlands, and often basking in a sunny position in the early part of the day.

[5] The distribution range extends from Israelite Bay to Gingin in the southwest of Australia, and at the off-shore island of Rottnest.