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Abstract

Considerable geographic variation occurs in the Tasmanian endemic butterfly, Oreixenica ptunarra, and
there is a high correlation between clusters of morphological characters and ecological factors, especially
climate and elevation. Evidence is presented for the existence of a longitudinal cline in phenotypic
characters of wing pattern and size, which is unrelated to the modest amount of variation in the male
genitalia (a possible surrogate for genetic variability). Butterflies from warmer, less cloudy eastern
Tasmania are larger and less dark in colour than those from the west, culminating in the small dark
populations of the north-west. This suggests selection for efficiency in thermoregulation as climatic
conditions become more marginal for adult activity from east to west. The prevailing subspecies
classification does not fully reflect the range of variation in this species. Conservation strategies that aim to
guarantee the survival of the collective phenotype of O. ptunarra based on this taxonomy are therefore
misinformed. The north-west populations are disjunct geographically and in features of phenotype, but are
not especially discrete in the morphology of the male genitalia. We propose that the subspecies angeli
Couchman and roonina Couchman be reduced to synonymy with nominotypical ptunarra Couchman, and a
new subspecies should be recognised to incorporate populations from the montane grasslands of northwestern
Tasmania.

Item Type:	Article
Authors/Creators:	McQuillan, PB and Ek, CJ
Journal or Publication Title:	Australian Journal of Zoology
ISSN:	0004-959X
DOI / ID Number:	https://doi.org/10.1071/ZO95050
Additional Information:	© CSIRO 1997
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