Bretscher, 1899, augm. Cernosvitov, 1928
Description
Small white or pink worms. When alive, finely spotted due to presence of reddish integumental glands. Chaetae by 2-5, 30-61 µm long, slightly sigmoid in the lateral view but almost straight when lying otherwise. Ventral chaetae lacking in XII. Male pores on distinct protuberances containing penial bulbs in XII. Clitellum in XII-1/2 XIII consisting of large cells arranged in transverse rows. Internal characters: Three pairs of small pharyngeal glands in V-VII (at 4/5-6/7) can have narrow dorsal connections; both dorsal and ventral lobes present. Coelomocytes elongate oval, finely granulated. No oesophageal or intestinal appendages. Blood light reddish; dorsal vessel reaches backward to XIII or XIV. Spermathecae in V consisting of small roundish ampulla, attached to oesophagus with a thin strand of tissue in V, and long bare ectal duct, sometimes with small gland at its ectal end in 4/5. Sperm arranged in circles in spermathecal ampullae. Male funnel barrel-shaped, length three times as large as width, with indistinct, slightly narrower collar. Vasa deferentia long and irregularly coiled in XII. Penial bulb large and compact. 1-2 mature eggs present at a time. Length 3-8 mm, segment number 25-40. Synonymy of the species is confused, as Bretscher described six slightly different taxa from riparian habitats in Switzerland, 1896-1905. They were listed as congeneric but independent species by Piguet and Bretscher, 1913. Cernosvitov, 1928, chose the name of the most typical representative of the group, Marionina riparia, when describing his own material elsewhere. Wilcke, 1957 treated the whole assemblage as one variable species, under the name Marionina maculata (maculata being the oldest of the six synonyms). Nielsen and Christensen, 1959 preferred the name used by Cernosvitov but confirmed the great variability of the taxon. The remaining five species have never been properly redescribed; they may be either synonyms of a single variable species, or the representatives of a superspecies. The red or reddish colour of cutaneous glands is characteristic of this taxon, but it is not well expressed in all populations. The most likely small enchytraeid in true freshwater habitats.
Burrowing in sediment.
Distribution
Western Palaearctic, China, Eastern Canada.
Ecology
In soil, on shores of freshwater, on bottom of lakes and rivers.
Reproduction
Sexual, with eggs laid in cocoons.
Literature
Bretscher, 1896: 513; Bretscher, 1899: 398, 400; Bretscher, 1900b: 449; Bretscher, 1901: 209; Bretscher, 1905: 663; Piguet and Bretscher, 1913: 100-104; Cernosvitov, 1928: 12-14, Fig. 2; Wilcke, 1957: 66-72; Nielsen and Christensen, 1959: 120-121, Figs 168-172; Timm, 1979: 122-127, Fig. 6; Chekanovskaya, 1981: 396-397, Fig. 200; Kasprzak, 1986: 168-170, Figs 580-593.