[Taxacom] Ghost moth as a subduction zone weed

John Grehan calabar.john at gmail.com
Fri Aug 28 13:50:04 CDT 2020

 For those interested, following article provides a biogeographic model for
the origin of a ghost moth genus (Phassodes) endemic to some Pacific
oceanic islands. Accessible at

  Taxonomic revision and biogeography of Phassodes Bethune-Baker, 1905
(Lepidoptera: Hepialidae), ghost moth descendants of a subduction zone weed
in the south-west Pacific. Grehan, J.R. & Mielke, C.G.C. Bishop Museum
Occasional Papers 136: 1–37 (2020)

 Abstract. Phassodes Bethune-Baker, 1905 is distributed in Fiji (P.
vitiensis (Rothschild, 1895)), the Solomon Islands (P. walteri sp. n.),
Samoa (P. samoa sp. n.), and American Samoa (P. tutuila sp. n.). It is the
only genus of Hepialidae endemic to oceanic islands. Monophyly of the genus
is supported by four unique features, and a sister group relationship with
the Australian genus Abantiades Herrich-Schäffer, 1855 is supported by four
shared derived features. There are also some features shared between
Phassodes and other genera: a) the southern Andean genus Andeabatis Nielsen
& Robinson, 1983 (shape and structure of the male genitalia), b) the
Peruvian Viridigigas Grehan & Rawlins, 2016 and c) the Chilean Puermytrans
Viette, 1951 (presence of a basal forewing scent gland). The distribution
of Phassodes coincides with the Vitiaz Trench, an extinct subduction zone
that marks a former boundary between the Indo-Australian and Pacific
plates. It is proposed that the common ancestor of Phassodes and Abantiades
diverged through vicariance when the subduction zone along the east coast
of Australia (East Gondwana), along with its island arc, began retreating
into the Pacific between 90 and 75 Ma. Survival of the genus on volcanic
islands is attributed to metapopulation dynamics, with continuous
transference of populations from older, subsiding islands to newly emergent
ones. This model suggests that Phassodes species originated much earlier
than the individual islands they now occupy.

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