George W. Gibbs

Victoria University of Wellington, Wellington, Wellington, New Zealand

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Publications (4)18.78 Total impact

  • Mary Morgan-Richards, George W. Gibbs
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    ABSTRACT: A phylogenetic analysis of New Zealand weta from the sub-family Deinacridinae is presented. Eighteen species were studied using 27 genetic characters (allozyme and cytogenetic) and 25 morphological characters. The combined data set produced a phylogenetic hypothesis with twelve well-supported nodes. Despite the great diversity of habitats and life styles exhibited by the eleven Deinacrida White species a well-supported bipartition separates them from the seven Hemideina Walker species. Six of the Hemideina species formed a monophyletic clade, with respect to H. broughi (Buller). Evolution of stridulatory ridges used for sound production in both defence and intraspecific communication appears to have occurred at least twice. Adaptation to the recent New Zealand alpine environment has also had multiple origins. Biogeographic interpretations from the phylogenetic hypothesis are discussed.
    Invertebrate Systematics 02/2001; 15(1):1-12. · 1.59 Impact Factor
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    Mary Morgan-Richards, George W. Gibbs
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    ABSTRACT: Scree weta from seventeen locations, covering the complete species range in the South Island of New Zealand, were examined using morphological characters studied by previous workers, as well as allozyme electrophoresis, and cytogenetics. The range of colour we describe does not support the four colour varieties proposed by previous workers for this species. Seven karyotypes are described, with diploid numbers ranging from 2n = 17(X0) to 2n = 22(XX). In contrast, little variation was found at 24 enzyme loci to distinguish different populations of scree weta. The level of allozyme variations suggests that colour and chromosome evolution has been rapid. Geographic structure is evident within both allozyme and chromosome variation but less so with colour variation. The extent of allozyme variation is in agreement with geological evidence that the Southern Alps of New Zealand are less than five million years old.
    Hereditas 04/1996; 125(2‐3):265 - 276. · 0.76 Impact Factor
  • Charles H. Daugherty, George W. Gibbs
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    ABSTRACT: Eleven populations of the Wellington tree weta, Hemideina crassidens (Blanchard, 1851), were compared with tree weta collected from Stephens Island (H. crassicruris Salmon 1950) and from Mt Holdsworth and Mt Arthur (H. brevaculea Salmon 1950), using 26 allozyme loci. The level of genetic differentiation is consistent with that found between conspecific populations, supporting the trend in the scientific literature to relegate both H. brevaculea and H. crassicruris to synonomy with H. crassidens. On the basis of morphological data indicating differentiation of the Stephens Island population, we conclude that H. crassicruris should be considered a subspecies of H. crassidens but H. brevaculea a synonym. There is an undescribed cryptic species, defined from the level of genetic differentiation, in Hawke's Bay.
    Journal- Royal Society of New Zealand 06/1995; 25(2):301-312. · 1.08 Impact Factor
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    ABSTRACT: The terrestrial New Zealand fauna has developed on an ancient landmass of continental origins that has had an increasingly isolated existence since the late Mesozoic. As a continental remnant, New Zealand harbours survivors of many ancient lineages many of which were once far more widely distributed. But New Zealand's fauna also resembles that of an isolated archipelago: many higher taxa are missing; some have undergone extensive radiations in situ; and levels of endemism approach 100% in many groups. Ecologically, the fauna is characterized by frequent niche shifts, gigantism, and extended life histories with low reproductive rates, factors that make many species vulnerable to human disturbance. Data continue to amass supporting the ecophysiological as well as phylogenetic distinctiveness of the fauna. Described taxonomic diversity, even of terrestrial vertebrates, continues to increase.
    Trends in Ecology & Evolution 12/1993; 8(12):437-42. · 15.35 Impact Factor