[Taxacom] New biogeography paper

John Grehan calabar.john at gmail.com
Wed Oct 3 10:05:36 CDT 2018


For those interested in such matters I draw attention to the following
recent publication, a copy of which can be obtained from me or the author.
It provides some excellent (in my view) and precise illustrations of
correlated tectonic and distributional congruence the belie suppositions of
chance dispersal. Also some interesting insights on non-Darwinian (other
than Darwin's laws of growth) modes of biological differentiation.

John Grehan

Heads M.J. (2018). The New Zealand grass Simplicia: biogeography, ecology
and tectonics

Abstract. This paper analyses biogeography and ecology in the grass
Simplicia, endemic to New Zealand, with respect to tectonic geology and to
distributions in other groups of plants and animals. There are disjunctions
and phylogenetic breaks at the Oparara basin (north-west Nelson), the
Western Province–Eastern Province tectonic boundary, the Alpine fault and
the Waihemo fault zone (Otago). Distribution boundaries at these localities
recur in many other taxa and coincide spatially with important fault zones.
General aspects of distribution and evolution in Simplicia are addressed,
using a set of critical questions posed by McGlone (2015) as a conceptual
framework. The biogeographic evidence suggests that the divergence of
Simplicia and of its species took place by vicariance, and that this was
mediated by tectonics. All individual plants of Simplicia have dispersed to
their present locality, but there is no evidence that chance dispersal with
founder speciation has occurred in the genus. Trends in these grasses, such
as spikelet reduction, are global and have evolved in many different
environments over tens of millions of years. This suggests that non-random
mutation has been more important than environment and natural selection in
directing the course of evolution


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