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Earthworm overview.png

Taxonomy and molecular phylogeny

1: Cuticule; 2: Circular musculature (striated tissue); 3: Longitudinal musculature (smooth tissue); 4: Dorsal setae; 5: Intestine; 6: Intestinal lumen and typhlosolis; 7: Ventral setae; 8: Ventral vein; 9: Ganglion (nerve cell cluster); 10: Dorsal artery; 11: Nervous cord; 12: Nephridial pinna; 13 Nephridial canal; 14: Nephridial pore.

The sub-order Lumbricina belongs to the phylum Annelida, Class Clitellata and order Haplotaxida. It is considered that this sub-order consists of the so-called "true earthworms". To its part, the family Haplotaxidae, sub-order Haplotaxina, is considered to be phylogenetically a basal group in regard to the classical terrestrial earthworms. The very first earthworm species, Lumbricus terrestris, was described by Carl Linnaeus in 1758. Savigny showed, in 1826, that earthworms were in fact composed of several species. Today, 23 families have been described and more than 5000 valid species are recognized.
From the first taxonomical descriptions to the present, earthworm classification has always been unstable... (short text on the recent history of the higher taxonomy)

Main references: Linnaeus, 1758; Savigny, 1826; Michaelsen, 1900; Stephenson, 1930; Yamaguchi, 1953; Brinkhurst and Jamieson, 1971; Jamieson, 1971; Reynolds and Cook, 1976, 1981, 1989, 1993; Sims, 1980; Jamieson, 1988; Csuzdi, 1995; Gregory and Hebert, 2002; Erseus and Ällersjö, 2004; Erséus, 2005; Blakemore, 2006; James and Davidson, 2012; Decaëns et al., 2013; Plisko, 2013

Biologie and ultrastructure

Earthworm bisexual reproduction.

Reproduction: Most earthworm species have a bisexual reproduction mode, few of them being exclusive or non-exclusive parthenogenetics (i.e. Eiseniella tetraedra or Pontoscolex corethrurus).

Main references: Satchell, 1980; Jamieson, 1981; Gregory and Hebert, 2002

Ecology and toxicology

Pasture in India with earthworm casts.

Lumbricina species are found in a large range of biota, from costal marine environments (i.e. Pontodrilus litoralis) to freshwaters (i.e. members of the Almidae family) and soils. However, most species are terrestrial, some of them living in mud or partially in freshwater. Haplotaxina species are mainly subservient to freshwater biota, including sediments.

Main references: Darwin, 1881; Lee, 1985; Greig-Smith et al., 1992; Edwards and Bohlen, 1996; Lavelle and Spain, 2001; Edwards, 2004; Bienert et al., 2012; Decaëns et al., 2013

Pictures (click to enlarge)