Archaeosynthemis occidentalis is a species of dragonfly of the family Synthemistidae,[3][4] known as the western brown tigertail.

[5] It is a medium-sized dragonfly with reddish-brown and yellow markings.

[5] It is endemic to south-western Australia where it inhabits boggy creeks and swamps.

[6][7] Archaeosynthemis occidentalis appears similar to Archaeosynthemis orientalis found in eastern Australia.

[5]