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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 7263

Kathryn A. Coates; Widespread polyploid forms of Lumbricillus lineatus (Muller) (Enchytraeidae: Oligochaeta): comments on polyploidism in the enchytraeids. Can.J.Zool. 73:1727-1734, 1995

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Studies of a small fresh collection of the marine intertidal enchytraeid oligochaete Lumbricillus lineatus (Muller) and taxonomic collections from 27 additional locations in Europe, Canada, and Australia reveal the presence of morphotypes corresponding to parthenogenetic autopolyploid forms, triploid, tetraploid, and pentaploid, of the species in all the regions represented by the collections. The extension of the range of these cytotypes from Europe to a virtually global distribution raises questions about the significance of parthenogenesis and polyploidism to their invasion of new habitats. Differences in reproduction rates and the ecological breadth of the different ploidy levels are not known. The geographical distribution and abundance of polyploids of L. lineatus, in themselves, do not provide conclusive evidence for the repeated origins of polyploids within the species, but strongly suggest that possibility. General theories link evolutionary polyploidy among animals with parthenogenesis, as seen in the polyploid forms of L. lineatus. However, polyploidism combined with out-crossing underlies the present taxonomic diversity of the family Enchytraeidae.