Dolomedes trux was first described by J. Lamb in 1911 from a female type specimen collected at Ithaca Creek, Brisbane.

[4] M. trux is found east of the Great Dividing Range in New South Wales and Queensland.

[2] M. trux hunts from beneath rocks and logs on the edges of slow-moving waterways, where they wait for prey to pass by with their front legs outstretched.

The long, sensitive trichobothriae on the front legs of this species allow them to detect vibrations in the water from small fish and frogs.

Upon detecting a suitable prey item in this manner, the spider dives into the water to subdue it, remaining in the substrate for up to 30 minutes.