[2] The family Parathelphusidae is now demoted to the rank of subfamily, as the Parathelphusinae, within the Gecarcinucidae.

This is thought to have occurred due to India drifting close enough to Southeast Asia to allow for biotic exchange between both regions.

As the Gecarcinucidae are a freshwater group that could not disperse via marine habitats, this indicates that temporary land bridges may have formed in the Eocene between India and Southeast Asia, allowing for the dispersal of freshwater organisms to India while it was still isolated.

Following the India-Asia collision, the Gecarcinucidae dispersed back into mainland Asia, and from there to Australasia.

[5] The Gecarcinucidae are thought to be the sister group to the Potamoidea (the superfamily comprising the Potamidae and Potamonautidae).