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31.
ALAN G. KNOX 《Ibis》1993,135(3):320-325
Museum collections are rich repositories of information. The specimens and the data they bear continue to provide new insights into ornithology and biological processes decades or even centuries after they were collected. The benefits to be gained from museum collections depend implicitly upon the accuracy of the information associated with the specimens and the correct interpretation of those data (Parkes 1989, Knox & Walters 1992). Collectors and dealers have often been suspected of fabricating data for a variety of reasons, but proven cases have been documented only rarely (e.g. Nicholson & Ferguson-Lees 1962). This paper examines one such case. 相似文献
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ALAN G. KNOX 《Biological journal of the Linnean Society. Linnean Society of London》1992,47(3):325-335
The holarctic crossbills Loxia have often been regarded as one of the classic examples of avian panmixia, despite a large number of named races, clines and other geographic variation. There are also reports of two or more 'subspecies' nesting sympatrically, without interbreeding. Crossbills feed almost exclusively on conifer seeds. Eruptions occur at times of cyclical cone crop failures; the birds involved may then breed in new areas for one or more years. Rather than being nomadic in their movements, to explain the clinal and/or area effects, it is suggested that erupting birds are reasonably faithful to core breeding areas, to which some subsequently return. Genetic continuity within a species is maintained through adjoining or overlapping core breeding areas. Although normally connected by intermediates, some populations apparently do not interbreed when they come together temporarily during irruptions. At such times, they behave as separate species, to which the term pseudospecies is applied. Mechanisms promoting rapid speciation and founder effects are discussed. 相似文献
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MATTHEW A. KNOX IAN D. HOGG CONRAD A. PILDITCH 《Biological journal of the Linnean Society. Linnean Society of London》2011,103(4):863-874
To investigate the role of vicariance and dispersal on New Zealand's estuarine biodiversity, we examined variability in mitochondrial cytochrome c oxidase subunit I (COI) gene sequences for the amphipod genus Paracorophium. Individuals from the two nominate endemic species (Paracorophium excavatum and Paracorophium lucasi) were collected from sites throughout the North and South Islands. Sequence divergences of 12.8% were detected among the species. However, divergences of up to 11.7% were also observed between well supported clades, suggesting the possibility of cryptic species. Nested clade analyses identified four distinct lineages from within both P. excavatum and P. lucasi, with boundaries between clades corresponding to topographical features (e.g. Cook Straight, North and East Cape). Sequence divergences of 3.7–4.9% were also observed within geographic regions (e.g. east and west coasts of the upper North Island). Genetic structure in Paracorophium appears to represent prolonged isolation and allopatric evolutionary processes dating back to the Upper Miocene and continuing through the Pliocene and early Pleistocene. On the basis of molecular clock estimates from sequence divergences and reconstructions of New Zealand's geological past, we suggest that sea level and landmass changes during the early Pleistocene (2 Mya) resulted in the isolation of previously contiguous populations leading to the present‐day patterns. COI genetic structure was largely congruent with previously observed allozyme patterns and highlights the utility of COI as an appropriate marker for phylogeographic studies of the New Zealand estuarine fauna. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 863–874. 相似文献
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