Ref ID : 7805
Chauncey G. Goodchild and George H. Irwin; Occurrence of nematodes Rhabditis anomala and R. pellio in Oligochaetes Lumbricus rubellus and L. terrestris. Trans.Amer.Micros.Soc. 90(2):231-237, 1971
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A stable thelyotokous population of nematodes isolated from the nephridia of the oligochaete Lumbricus rubellus was identified as Rhabditis anomala Hertwig, 1922. Reproduction was found to be by mitotic parthenogenesis, and pseudogamy and spermatozoa were produced within the female. R. anomala was found with Rhabditis pellio, a dioecious species, in the nephridia of L. terrestris. R. anomala has 20 chromosomes and could be a triploid derived from a diploid species such as R. pellio or R. maupasi, each with 14 chromosomes. Hermaphroditism may be a function of the X: autosomal ratio. Some investigators, assuming that only R. maupasi occurs in lumbricids, concluded that the species could reproduce sexually or parthenogenetically. This conclusion must be re-evaluated in view of the knowledge of a thelyotokous species infecting the same host oligocaete.