Ashley Field report on Harpago in Queensland, Australia:
- "In general Harpago chiragra (Linnaeus, 1758) and Harpago rugosus (Sowerby II, 1842) do not occur in the same area here in Queensland but both have been recorded from Helix Reef which is far offshore from Townsville, so they could potentially occur together. I have also never come across a specimens that could not be readily identified as H. chiragra or H. rugosus. In general Harpago chiragra occurs on the Great Barrier Reef and Harpago rugosus on the Coral Sea Reefs but there are some isolated reefs which could have both together. They differ a bit in their behaviour and habitat as well. Harpago chiragra usually occurs on the seaward margin in shallow water on the hard platform of reefs in the Great Barrier Reef, conversely Harpago rugosus appears to be a lagoon dwelling shell and is from somewhat deeper habitats. Harpago chiragra is conchologically sexually dimorphic whereas H. rugosus is much less dimorphic and males and females can be hard to distinguish. Together they are very interesting species as they both have quite a different capsize behaviour to other spider shells."