Chaetonotus (Chaetonotus) naiadis Balsamo & Todaro, 1995, Balsamo & Todaro, 1995

Kånneby, Tobias, 2013, New species and records of freshwater Chaetonotus (Gastrotricha: Chaetonotidae) from Sweden, Zootaxa 3701 (5), pp. 551-588: 563-564

publication ID

publication LSID


persistent identifier

treatment provided by


scientific name

Chaetonotus (Chaetonotus) naiadis Balsamo & Todaro, 1995


Chaetonotus (Chaetonotus) naiadis Balsamo & Todaro, 1995  

( Fig. 7 View FIGURE 7 )

Localities: Saltö, Bohuslän (N 58 º 52 ’ 21 ’’; E 11 º 07’ 34 ’’), November 13, 2008; Abisko, Lapland (N 68 º 21 ’ 23 ’’; E 18 º 47 ’ 59 ’’), July 5, 2010.

Material: 3 specimens.

TL, 137–140 µm; FL, 14–18 µm; AL, 7–8 µm; PhL, 32–33 µm; MD, 4–5 µm; CW, 12–13 µm; TNC, 28–31; DC, 20–21; DR, 27–28; VLC, 8–11; HS, 2 x 2 µm; NS, 2– 3 x 2–3 µm; DS, 3– 4 x 2–3 µm; HSp, 1–2 µm; NSp, 1– 2 µm; DSp, 1–2 µm; VC, 5–6; VTS, 5 x 3 µm.

Five-lobed head with two pairs of cephalic sensory ciliary tufts; anterior pair with mostly short cilia, but one cilium substantially longer than the others. Hypostomium developed as a small sub-rectangular plate. Two pairs of dorsal sensory bristles; anterior pair inserted at U 28 and posterior pair emerging from rounded triangular doublekeeled scales at U 78–79. Furca straight with adhesive tubes constituting approximately half of the total furca length. Dorsal body surface covered by small three-lobed scales with minute simple spines. Scales and spines only increase slightly in size towards the posterior end. An area anterior to the caudal incision and between the posterior sensory bristles has scales spaced wider apart than the rest of the dorsal surface.

Ventrolateral scales and spines similar to those of the dorsal surface, but sometimes with spines reaching lengths up to 3–4 µm. Ventral interciliary area covered by small rounded keeled scales that seem to fuse with the body surface anterior to the 2 or 3 posteriormost rows. Ventral terminal scales suboval to sub-rectangular and keeled. Ventral ciliation in two separate longitudinal bands, that widen on the head.

Mouth subterminal. Pharynx without swellings, only widens slightly towards the PhIJ at U 28–31. Intestine straight with anus at U 85–87.

The Swedish specimens were all adults in parthenogenetic phase. Compared to the description by Balsamo & Todaro (1995) they are just below the upper limits of the total body length (140 µm) reported for the species. Previously reported from Italy (Balsamo & Todaro 1995).