Chaetonotus (Chaetonotus) oculifer Kisielewski, 1981

Kånneby, Tobias, 2013, New species and records of freshwater Chaetonotus (Gastrotricha: Chaetonotidae) from Sweden, Zootaxa 3701 (5), pp. 551-588 : 564-565

Chaetonotus (Chaetonotus) oculifer Kisielewski, 1981

( Fig. 8 )

Synonyms: Chaetonotus ocellatus Martin 1981 [syn. Kisielewski 1998; see also Balsamo et al. 2009]

Localities: Sphagnum spp. bog at highway E10, Lapland (N 68º 26’ 04’’; E 18º 14’ 53’’), July 1, 2010; Freshwater Rockpool among Sphagnum spp., Hållö, Bohuslän (N 58º 20’ 03’’; E 11º 12’ 50’’), July 14, 2009; Freshwater Sphagnum spp. rockpool, Islandsberg, Bohuslän (N 58º 12’ 38’’; E 11º 25’ 09’’), July 19, 2009; Lake with grass at highway E10, Lapland (N 68º 20’ 915’’; E 19º 02’ 210’’), July 6, 2010; Bog at highway E14, Jämtland (N 63º 21’ 25’’; E 12º 35’ 40’’), July 10, 2008.

Material: 7 specimens.

TL, 118–127 µm; FL, 13–16 µm; AL, 7–8 µm; PhL, 30–32 µm; MD, 4–5 µm; CW, 9–10 µm; TNC, ~18; DC, 10–12; DR, 22–24; VLC, 7–9; HS, 2– 3 x 2 µm; NS, 3 x 2–3 µm; DS, 4 x 3 µm; HSp, 2–4 µm; NSp, 3–4 µm; DSp, 4–7 µm; VC, 7–8; VTS, ~ 5 x 2 µm.

Head clearly five-lobed with two pairs of long cephalic sensory ciliary tufts. Cephalion, epi- and hypopleurae well developed. On the head one pair of ocellar granules, approximately 1 µm in diameter. Hypostomium poorly developed as an almost squared plate. Anterior dorsal sensory bristles apparently absent, posterior pair emerging from double-keeled scales at U81. Furca straight with adhesive tubes constituting approximately half of the total furca length. Dorsal body surface covered by three-lobed scales with simple short and gently curved spines. Both scales and spines increase in size towards the posterior end.

Interciliary area with keels or more or less well developed rounded keeled scales. Ventral terminal scales almost rectangular, with a very short simple spine. Ventral ciliation in two separate longitudinal bands.

Small subterminal mouth. Pharynx with a slight posterior swelling. PhIJ at U28–30. Intestine straight with anus at U83–85.

All Swedish specimens except one juvenile were in parthenogenetic phase and in general agree well with literature data. Dorsal sensory bristles have not been reported or described for C. (C.) oculifer (Kisielewski 1981) . Moreover, three of the specimens had scales developed in the interciliary area, which is in contrast to Kisielewski (1981) who reported that this area is covered by keels only.

Previously reported from France (Grilli et al. 2008), Great Britain (Martin 1990), Poland (Kisielewski 1981), Russia (Tretjakova 1989), Sweden (Kånneby et al. 2009), Brazil (Kisielewski 1991) and Canada (Schwank, 1990)

Figures

FIGURE 8. Chaetonotus (C.) oculifer. A) Dorsal view of anterior body showing an ocellar granule and distribution of scales and spines. B) Ventral view showing ventral terminal scales and scales of the interciliary area. Scale bars: 10 µm.