Mnesarchaeidae, Eyer, 1924

Grehan, John R. & Mielke, Carlos G. C., 2018, Evolutionary biogeography and tectonic history of the ghost moth families Hepialidae, Mnesarchaeidae, and Palaeosetidae in the Southwest Pacific (Lepidoptera: Exoporia), Zootaxa 4415 (2), pp. 243-275 : 250

(1) Mnesarchaeidae in the Southwest Pacific

This family is not simply a taxon nested within a larger exporian group to be viewed as a derivative of a mainland or continental ancestor. Mnesarchaeidae are a ‘globally basal’ group, as its sister group is made up by all other Exoporia which has a global distribution. This globally basal pattern is shared by 38 other animal and plant taxa located around the Tasman basin, of which 22 are endemic to New Zealand ( Heads 2017a). This global sister group relationship for the Mnesarchaeidae does not conform to the centre of origin/dispersal model in which the local clades are derived by dispersal from outside the region. The endemism of Mnesarchaeidae in New Zealand is consistent with the family originating locally by vicariance from a more or less globally distributed Exoporian ancestor resulting in descendants that were either localized ( Mnesarchaeidae ) or widespread (Hepialoidea).

A molecular divergence estimate of [at least] 90 Ma for the Exoporia was seen by Gibbs (2016) to meet the expectations of vicariance for the origin of Mnesarchaeidae in New Zealand, since it predates the geological separation of New Zealand from Gondwana ̴80 Ma. Under a vicariance model the localized distribution of the Mnesarchaeidae suggests that the initial phylogenetic break separating this group from all other Exoporia occurred near the margins of East Gondwana. Differentiation of a formerly continuous distribution range of ancestral Exoporia ( Fig. 7a ) may have resulted from isolation involving a major tectonic event such as extensive volcanic activity along a large silicic province at ̴135 Ma ( Fig. 7b ). This tectonic disruption would have resulted in the Mnesarchaea lineage having a small distribution range separated from the much wider distribution range of its sister group (Hepialoidea). Subsequent range expansion of the Hepialoidea would be responsible for the present day sympatry of the two groups ( Fig. 7c ).

Figures

FIGURE 7. Hypothetical vicariance origin of Mnesarchaeidae: (a) widespread ancestor over East Gondwana in heavy stippling; vicariance mediated by tectonic disruption (such as the large silicic province in red) resulting in isolation and differentiation of Mnesarchaeidae (horizontal wavy lines) with a small distribution range to the east, and Hepialoidea (light stipple) with a large, almost global, distribution range to the west; (c) subsequent range expansion by Hepialoidea resulting in sympatry with Mnesarchaeidae. Tectonic outline from Strogen et al. (2017).