Purported sister-group relationship of Phreatoicopsis
and Synamphisopus is supported by molecular data.
Recent morphological analysises and molecular data indicate
an ancestral relationship of South African genus
Mesamphisopus to (Phreatoicopsis +
Synamphisopus).
In Phreatoicopsis no distinct patterns of population
structure could be discerned among the Otway and Grampian
populations; some haplotypes were found at both localities,
and some haplotypes were unique.
Synamphisopus preliminary data indicate that sequence
divergence, i.e. genetic diversity, may be greater among
Synamphisopus populations than in Phreatoicopsis
populations.
