Eudrilidae

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Eudrilid earthworms are restricted to Africa (Ethiopian Region) as natives. One species, Eudrilus eugeniae has become widely distributed around the warmer parts of the world and is cultured as the ‘African Night Crawler’. The male pores of eudrilids lie in segment 17, as is also typical of Ocnerodrilidae, with which they have been considered to be closely related. Molecular studies do not support this relationship but suggest glossoscolecid affinities.

Eudrilids differ from the large family Megascolecidae in having euprostates, i.e. tubular prostates through which the male ducts discharge and which appear to be reflexed modifications of these ducts, thus more resembling the atria of lumbriculids and monilgastrids than the separate prostates (metaprostates) of megascolecids. Eudrilids further differ from megascolecids, and ocnerodrilids, in evolutionary migration of the spermathecae from the basic earthworm anterior location (in and/or anterior to segment 9) to the vicinity of the ovaries (in 13; sometimes posterior to the male pore) and in the development in many of internal fertilization, foreign sperm passing internally from the spermathecae to ovisacs, on the oviducts. Elsewhere in the Oligochaeta, only the Phreodrilidae are suspected of having internal fertilization.

The reproductive system in the subfamily Eudrilinae, to which the African Night Crawler belongs, is more complex than that of the Pareudrilinae. In the Pareudrilinae transitions are seen in Stuhlmannia from ovaries free in the ovarian segment, presumably with fertilization in the cocoon, to ovaries enclosed within the spermathecal system and with presumed internal fertilization. Penetration of the wall of the spermatheca by sperm from the partner, thus gaining access to the ovisacs, has been demonstrated in Stuhlmannia variabilis of Uganda.

[edit] Bibliography

  • Jamieson, B.G.M. 1967. A taxonomic review of the African megadrile genus Stuhlmannia (Eudrilidae, Oligochaeta). Journal of Zoology (London) 152: 79-126.
  • Jamieson, B.G.M. 2006. Non-leech Clitellata. (with contributions by Marco Ferraguti). Pp. 235-392. In Reproductive Biology and Phylogeny of Annelida. Series Editor B.G.M. Jamieson. Volume 4. Editors Greg Rouse and Fredrik Pleijel. Science Publishers, Enfield, New Hampshire, U.S.A. Jersey, Plymouth, U.K. ISBN 1-57808-313-3.
  • Sims, R.W. 1967. Earthworms (Acanthodrilidae and Eudrilidae) from Gambia. Bull.etin of the British Museum of Natural History 16: 1-43.
  • Zicsi, A. 1997. Contribution to the knowledge to the earthworm fauna of East Afrika (Oligochaeta: Eudrilidae), with description of a new species of Polytoreutus. Revue Suisse de Zoologie. Dec. 104
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