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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

[ref. ID; 5857 (Christer Erseus, 1984)]

Tubificidae

Subfamily Rhyacodrilinae

A cosmopolitan, diverse group of both freshwater and marine genera. Prostates diffuse (the free ends of elongated prostatic cells arise from the inner atrial epithelium, penetrate the atrial wall individually, and form a diffuse layer covering a great part of the atrial ampulla), or irregularly scattered in two or more clusters of cells broadly attached to the atrial surface, or absent. Dorsal setal bundles complex (with hairs and pectinates) in about 50% of the freshwater species; only bifid setae in the marine forms (except Jolydrilus and a few Monopylephorus species) and the remaining freshwater species. Some genera (Branchiura, Bothrioneurum, Macquaridrilus) with elaborate, highly modified male ducts. Coelomocytes generally abundant and conspicuous. Spermatozeugmata not found in spermathecae. Body wall always smooth.

Subfamily Phallodrilinae

An extremely diverse, cosmopolitan marine group, with a few freshwater representatives. Prostates generally soild and stalked, two per atrium. In some genera, one or both prostates absent, and in one genus (Discordiprostatus; see Baker 1982) anterior prostate diffuse. Somatic setae bifid, secondarily single-pointed in a few species. Genital setae sometimes highly modified. Coelomocytes not abundant. Sperm generally loose in spermathecae, but forming roundish spermatozeugmata (?) in a few species (Bathydrilus). Body wall smooth in all species except one (Duridrilus tardus; see Erseus 1983)

Subfamily Telmatodrilinae

A small group of freshwater species, with discontinuous distribution (Holarctic and Tasmania). Prostates solid and stalked, more than two per atrium (possibly only two in the poorly known Telmatodrilus bifidus). Hair and pectinate setae common in dorsal bundles. Coelomocytes not abundant. Spermatozeugmata (?) found in spermathecae of some species; sperm loose in other species. Body wall often encrusted with foreign matter, and bearing scattered sensory papillae.

Subfamily Aulodrilinae

A small group of freshwater species inhabiting tubes, and generally using posterior (more or less unsegmented) ends as gills. Prostates solid and stalked (may be broadly attached in some species, but this has been little studied), one per atrium. Hair setae, and other modified setae (pectinates, oar-shaped bifids, etc.), often present in dorsal bundles. Setae always numerous. Many species reproduce asexually by fragmentation, some species have genital organs shifted forwards. Coelomocytes not abundant. Sperm in loose, random masses in spermathecae. Body wall always smooth.

Subfamily Limnodriloidinae

A large, cosmopolitan group of marine genera, most of which occur in muddy sands of warmer seas. Prostates solid, one per atrium, broadly attached to ental part of atrium (atrial ampulla). Somatic setae always bifid. Oesophagus modified in segment IX of most species; either bearing a pair of diverticula, or enlarged and glandular. Coelomocytes not abundant. Sperm bundled, or as spermatozeugmata (?) in spermathecae. Body wall papillate (encrusted with foreign matter) in some species (Tectidrilus).

Subfamily Tubificinae

Most of the freshwater genera, and a few marine ones. Appears cosmopolitan, at least in freshwater, but this is probably a reflection of the distribution of some highly peregrine species (Tubifex tubifex, Limnodrilus hoffmeisteri). Prostates solid, stalked, one per atrium, when present: absent in a few species. Hair and pectinate setae in dorsal bundles of many species, more so among limnic than among marine forms. Penes generally well developed, often with cuticular sheathes. Coelomocytes not abundant. Spermatozeugmata found in spermathecae. Body wall papillate in some species.