Linyphiidae has around 4,300 described species in 578 genera worldwid, the second largest family of spiders after the Salticidae. Most are tiny. New species are still being discovered throughout the world, and the family is poorly known. There are six subfamilies, of which Linyphiinae (the sheetweb spiders), Erigoninae (the dwarf spiders), and Micronetinae, contain the majority of described species. (Wikipedia.)
A small fast-running dark male spider body length 1.5-2mm possibly Erigone sp. but these spiders are notoriously had to identify. Dr Ron Atkinson...
The Linyphiids in Australia are very understudied. It will be difficult to determine what genera we are finding until some major revisions are done.