This beetle is always dark. Close inspection will reveal that it comes in at least two varieties, one entirely black.
The second variety has subtle red lines on the elytra. Another (rare) has brown elytra. This beetle is common and widespread along the east coast including Tasmania. It always has very fine and virtually imperceptible striae puncturations. It has strong foveae on the pronotum (dimples in its cheeks).
These are crepuscular and found most easily under bark of candlebark/manna gum types which offer large spaces for them to hide.
This beetle is Paropsisterna morio. It was found under bark of manna gum. It is entirely black sometimes with brown or lighter lines in the interstices (spaces between the striae). The elytra are highly nitid (glossy) and striae almost entirely lacking grooves. This beetle is variable in size but often large and elongate and very convex. I have seen one with a red neck (back of head) and assume it to be morio. I have not seen these except under bark. They are nocturnal and feed on large leaved eucalyptus such as manna gum. These glossy, black, nocturnal beetles feature foveau (large dints) on the pronotum, one on each side and this species also has a large crease in the elytral base directly behind these foveau. Paropsisterna morio is widespread from Tasmania to Queensland.