Juget, 1987
Description
Small smooth, pink worms. Anterior dorsal bundles with 1-2 hair chaetae, up to 250 µm long, and 1-3 pectinates, 55-67 µm long, with upper tooth thinner and slightly shorter, and few intermediate teeth. Posterior dorsal bundles with 1-4 sigmoid crotchets with simple sharp tip; in midbody, a transition zone with rudimentary upper tooth in dorsal crotchets. Anterior ventral bundles with 3-6 bifid crotchets as long as dorsal pectinates but with teeth equally thick, while upper one is 1.5-2.5 times as long. Posterior ventral chaetae by 1-5, as long as dorsal ones but bifid, with upper tooth thinner and longer than lower one. Penial chaetae in XI (or X, or XII) 1-2 per bundle, 66-72 µm long and up to 5 µm thick, with strongly reduced (sometimes missing) upper tooth. Clitellum not observed. Coelomocytes abundant. Length 3-6 mm, up to 50 segments. Differing from congeners in the sharp difference between anterior and posterior chaetae both in dorsal and ventral bundles; as well as in the variability of the position of reproductive system, caused by prevalence of asexual reproduction.
Burrowing in sediment.
Distribution
Floodplain of the Rhône River in France.
Ecology
In freshwater, known only from groundwater. Forming cysts composed of sediment cemented with mucus.
Reproduction
Variability of the position of reproductive apparatus, as well as ready autotomy and regeneration of both ends indicate predominantly asexual reproduction by architomy, or fragmentation. Sexual reproduction possible but not observed.
Literature
Juget, 1987: 108-111, Figs 2-4; Giani et al., 2001: 65-74.