So how much variation is there in size in the E. australiasiae? These range from maybe 30 mm up to over 50 mm. I would have thought they would be closer in size than that unless some are male and some female. They also vary in their degree of 'hairiness' around the head.
There is a lot of variation in colour and pattern in these. The general shape and size is within that band you state.. Have a look on the Atlas of Lliving Australia for this species and you will see the variation.