Abstract The nematode worm Scottnema lindsayae
(Cephalobidae) was found near the base of the Beard-more Glacier in the Transantarctic Mountains 83.48°S, over 5 ° further south than previously recorded. Identi-Wcation was conWrmed using morphological analyses of males, females and juvenile stages, and by DNA sequencing of the ITS1 region of the r...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.664.8645 http://adamslab.byu.edu/Portals/74/docs/Papers/Adams2007Polar+Biology.pdf |
| Summary: | (Cephalobidae) was found near the base of the Beard-more Glacier in the Transantarctic Mountains 83.48°S, over 5 ° further south than previously recorded. Identi-Wcation was conWrmed using morphological analyses of males, females and juvenile stages, and by DNA sequencing of the ITS1 region of the ribosomal RNA tandem repeat unit. These data revealed no discern-able morphological or ITS rDNA sequence variation between the extreme southern population of S. lind-sayae and disparate populations from the McMurdo Dry Valleys in south Victoria Land (77–78°S). Based on these results, we suggest that broadcast dispersal, with accompanying high rates of gene Xow, establish the extreme southern distribution of the phylum Nem-atoda. High abundance, low rates of diversiWcation and lack of an apparent biogeographic structure across lati-tudinal and environmental gradients implies that their presence in simple Antarctic soil ecosystems is stable, so long as physical and biological controls on their dis-tributions remain within viable parameters. Recent evidence that S. lindsayae populations are in decline suggests that their high dispersal rates are insuYcient to buVer current, unfavorable environmental changes and may foreshadow longer-term ecosystem disrup-tion. |
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