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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

[ref. ID; 7651 (Tamara S. Perel, 1973)]

Systematics of Lumbricidae

The system proposed by Daniel Rosa (1893) to divide earthworms of the family Lumbricidae into the genera was used for a long time, being but somewhat reconstructed by Michaelsen (1900) and Svetlov (1924). Further obtained data showed significant misadvantages of this widely accepted generic systematic of Lumbricidae, as Pop (1941) convincingly proved. Some attemps to revise the generic system of the family Lumbricidae have been undertaken during last decades (Pop 1941, Omodeo 1956, Bouche 1972, Gates 1969). Some new characters have been proposed for this purpose. Pop recomended to use the purple pigmentation and position of longitudinal muscle fibres as characters of a high taxonomic value; Omodeo - the number of calciferous glands and chromosome numbers; Bouche - the position of nephropores and the structure of typhlosolis. Sometimes taxonomists do overestimated the diagnostic significance of characters introduced by them. Thus Pop (1941) reconstructed the generic systematics of Lumbricids basing on presence or absence of purple pigmentation, though this character varies even within the frame of the same species - e.g. in Eisenia nordenskioldi (Eisen), in Allolobophora japonica Michaelsen, in Dendrobaena platyura (Fitzinger). Gates (1969), rejecting all characters previously adopted in the generic system of Lumbricidae, gives diagnoses of genera based on the form of nephridal bladders, adding only some comments concerning the position of califerous glands. He supposes that the genus Bimastos (= Bimastus) Moore, 1893, which he regards in somewhat changed volume, according to his new diagnosis as well as a recently discriminated by him genus Eisenoides Gates, 1969, are to be appreciated as genera of American origin. For these genera (according to Gates) the U-shaped (hair-pin-like) nephridial bladders are typical. Other species he has examined [Dendrobaena mariupolienis Wyssotsky, Dendrobraena veneta (Rosa), Dendrobaena hortensis (Michaelsen), Eiseniella tuberosa Svetlov (= Allolophora bashkirica Malevic)], possessing sausage-like nephridial bladders, Gates refers to the genus Eisenia Malm, 1877, giving a new diagnosis for this genus taking into account the shape of nephridial bladders and the position of calciferous glands. Up to recent time the structure of nephridia and in particular that of nephridial bladders was not taken into consideration for the discrimination of Lumbricidae taxa and was not even mentioned in descriptions of species belonging to this family. But peculiarities of the structure of nephridia are used in the taxonomy of other soil dwelling Oligochaeta. Thus, Overgaard Nielsen and Christensen (1959) when listing taxonomic criteria used in the systematics of Enchytraeidae put the structure of nephridia among other significant characters. Pickford (1937) had success when she applied the characteristics of the shape of nephridia and presence or absence nephridial bladders when she elucidated the taxonomic position of several Acanthodrilinae (Megascolecidae). Lee (1959), when evaluating differences in the structure of nephridial bladders as a diagnostic characters, stresses that it is reliable and can be applied not for the discrimination of species only, but also for the identification of genera among Megascolecids.
  1. U-shaped bladders
  2. Fish-hook-like bladders
  3. Saussage-like bladders
  4. Variations of sausaage-like bladder type I. sack-saussage-like shape, type II sack-like shape