Polymerurus rhomboides ( Stokes, 1887 )

Kånneby, Tobias, 2011, New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden, Zootaxa 3115, pp. 29-55 : 49

Polymerurus rhomboides ( Stokes, 1887)

( Figure 16 )

Localities. Lake Trösvattnet, Västmanland (N 59º 33’ 21’’; E 14º 29’ 23’’).

Material. 1 specimen. TL, 273 µm; FL, 80 µm; PhL, 50 µm; MD, 13 µm; DC, 20–22; DR,>50; SCA, 18; TS, 6– 7 x 3; VC, 10.

Large elongated species with three-lobed head and well developed cephalion and pleuria. Hypostomium well developed as a transverse bar behind the subterminal mouth. Furca very long, divided into 18 segments. Body covered by oval smooth stalked scales without spines. Interciliary area covered by smaller scales similar in shape to the dorsal ones. Ventral ciliation in two longitudinal bands. Pharynx widens towards the pharyngeal intestinal junction. The Swedish specimen falls within the ranges of previously reported literature data.

This species is widely distributed in Europe (see e. g. Marcolongo 1910; 1914; Mola 1932; Valkanov 1937; Rudescu 1967; Martin 1981; Schwank 1990; Kisielewski 1998) and is also reported from Israel ( Kisielewski 1999), Japan ( Saito 1937), Korea ( Lee & Chang 2000); Cameroon (Togouet Zébaz et al. 2007), Canada ( Schwank 1990), United States ( Stokes 1887; Davison 1938; Anderson & Robbins 1980), Argentina ( Grosso 1975; Grosso & Drahg 1983), Brazil ( Kisielewski 1991) and Australia ( Hochberg 2005).

Figures

FIGURE 16. Polymerurus rhomboides. A) Habitus. B) Shape of pharynx and cephalion. C) Dorsal view of mid-trunk showing scales. Scale bars: A, 50 µm; B and C, 20 µm.