Chaetonotus (Primochaetus) soberanus Grosso & Drahg, 1983

Kånneby, Tobias, 2013, New species and records of freshwater Chaetonotus (Gastrotricha: Chaetonotidae) from Sweden, Zootaxa 3701 (5), pp. 551-588 : 580

Chaetonotus (Primochaetus) soberanus Grosso & Drahg, 1983

( Fig. 21 )

Localities: Artificial pond, Nybro, Småland (N 56º 44’ 89’’; E 15º 54’ 27’’), June 28, 2008.

Material: 1 specimen.

TL, 152 µm; FL, 24 µm; AL, 20 µm; PhL, 30 µm; MD, 5 µm; CW, 14 µm; TNC, 8; DC, 4; DR, 19–20; VLC, 4; HS, 5 x 4 µm; NS, 5– 6 x 5–6 µm; DS, 10– 14 x 10–14 µm; HSp, 3–6 µm; NSp, 6–7 µm; DSp, 12–20 µm; VC, 3– 4.

Head clearly five-lobed with two pairs of short cephalic sensory ciliary tufts. Cephalion, epi- and hypopleurae developed. Hypostomium absent. At least the posterior pair of dorsal sensory bristles present, emerging from round double-keeled scales. Furca weakly tong-shaped with adhesive tubes constituting almost 4/5 of the total furca length. Dorsal body surface on head- and neck region covered by crescent-shaped to round scales with short straight simple spines. Lateral spines in head- and neck region are longer, up to 10–12 µm in length. Dorsal trunk region covered by round to sub-oval scales with simple straight spines. In the posteriormost dorsal trunk region scales are much smaller with shorter spines. One pair of long parafurcal spines, up to 30 µm in length, present.

Ventrolateral scales are round to oval with long slightly curved spines, up to 28 µm in length. Anterior part of the ventral interciliary area with smooth plates much resembling those of Lepidodermella squamata (Dujardin, 1841) and Chaetonotus maximus . In the intestinal region the ventral interciliary field is covered by transverse plates with jagged anterior ornamentation. Posteriormost part covered by 3–4 columns of round to oval keeled scales; spines could not be seen. At the caudal incision two ventral pairs of smaller scales present, the middle pair carries short but stout spines clearly visible between the furcal branches.

Pharynx, with anterior and posterior swellings. PhIJ at U23. Intestine straight with anus at U70.

The Swedish specimen is larger than the Argentinean specimens but they are the same morphological species. C. (P.) soberanus has long dorsal and lateral spines as opposed to the European records of the morphologically closely related Chaetonotus (Primochaetus) ophiogaster Remane, 1927 .

Previously reported from Argentina (Grosso & Drahg, 1983).

Figures

FIGURE 21. Chaetonotus (P.) soberanus. A) Dorsal view showing distribution and shape of scales and spines. B) Ventral view showing the peculiar ornamented scale plates of the interciliary area. Scale bars: 20 µm.