Spined Citrus Bug

Large bug often found in our lemon tree. It actually affects the lemon. Update 8/3/2017: I just moved all the nymph photos that I had posted under Shiny Pattern Shield Bug, or Commius elegans. I am highly confident that my identification is now correct. It is based on http://www.bowerbird.org.au/observations/19253. Also, the nymph was found in close proximity to the adult on two consecutive days while Commius elegans is not documented for the area yet. There are many, very similar nymph representations on ALA and on the web with some of them probably misidentified. However, it looks as if some species look very similar. (Here some of them: Dindymus versicolor, Scutiphora pedicellata, Commius elegans, Tectocoria diophthalmus, Coletichus sp., Glaucias amyoti)