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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

[ref. ID; 5945 (Ralph O. Brinkhurst & H.R. Baker, 1979)]

Subfamily Tubificinae Eisen

Many of the genera in this subfamily contain no salt-water species (Ilyodrilus, Limnodrilus, Antipodrilus, and the preculiar Peipsidrilus Timm (Timm 1977), which fit this subfamily apart from the absence of spermatozeugmata) while those that do, have them limited to inland salt springs or to the Black and Caspian Seas (Psammoryctides, Potamothrix, and Isochaeta; through Isochaeta hamata Moore from the Acushnet River, New Bedford, MA, inhabits a site where salt water is found in the water column at least, and I. michaelseni (Last.) is known from brackish sites in Europe). The marine species of Tubifex and Peloscolex have created taxonomic problems for some time, but now that an increasing number of marine forms have been described it has become clear that they mostly belong to the distinct genus Tubificoides Lastockin (1937) emm. Holmquist 1978. The species transferred to the genus all have strikingly similar male efferent ducts, and are all quite small marine species. The setal form varies as it does in a number of tubificid genera. Holmquist (1978) places Peloscolex benedeni in the new genus Edukemius by virtue of very small differences in the histology of the atria. It too is regarded here as a Tubificoides, although it might be reasonably separable at the subgeneric level as it is larger and more papillate than most species, has unusual setae, and has the minor differences in male duct histology described by Holmquist (1978).

Subfamily Rhyacodrilinae Hrabe

There are no marine species of Paranadrilus, Epirodrilus, Rhyacodrilus, or Bothrioneurum, but the genus Monopylephorus contains more coastal marine than freshwater species. Jolydrilus jaulus Marcus is recorded from brackish water in Brazil.

Subfamily Phallodrilinae Brinkhurst

This subfamily contains mostly marine species that have been described for a variety of small genera, several monotypic. Careful study of many of these by C. Erseus (personal communication) has demonstrated that earlier descriptions often overlooked small details, especially the posterior prostate glands typical of the majority of phallorilines, and other anatomical features that he well use to revise the definition elsewhere.