I found seven specimens of this species of spider on Scribbly gums and each spider appeared to have caught a Sugar ant of the genus Campanotus. Given the similarity in colour between the spider and her prey, and the fact that I found so many on different trees I conclude that this spider might be a specialist. Bad news for Sugar ants. I wonder if eating too many sugar ants is bad for the spider's mandibles?
Turns out the species IS an ant specialist and high-speed footage shows the spider literally somersaults over its prey to catch it.