The relict family Myerslopiidae is restricted to New Zealand and South America while the Melizoderidae consist of two genera restricted to South America. The great diversity of Neotropical taxa suggests that the group originated in that region.
The distribution of the Myerslopiidae and Melizoderidae families suggests that they originated in the Neotropics, a region encompassing much of Central and South America. This is inferred from their restricted ranges to New Zealand and South America.