Prostoma viera, Timofeeva, 1912

Kajihara, Hiroshi, 2025, A taxonomic revision of the freshwater monostiliferous hoplonemertean genus Prostoma Dugès, 1828 (Nemertea: Eumonostilifera): a radical solution or an over-lumping?, Zootaxa 5646 (4), pp. 451-500 : 486

5. Prostoma viera

(Annex Fig. 1E)

Description. Body about 10 mm long, cylindrical in shape; head not demarcated from remaining body; posterior end rounded. Main colour dirty yellow. Immediately behind posterior pair of eyes, wide ring of dotted, yellowbrown pigment present; from this ring, narrow stripe of similar pigment stretches dorsally. Eyes six; small grain of additional pigments (same as eye pigments) present around each of eyes in middle pair.

Locality. Silt from a depth of 150 m at the exit of the bay (Annex Fig. 2 , XXIV, dredging number 38).

Remarks. The original figure (рис. 5) shows two accessory stylet pouches, each containing three accessory stylets; now Tetrastemma viera ( Timofeev, 1911) , although the three pairs of eyes suggest that this species may not belong in Tetrastemma .

Figures

FIGURE 2. Prostoma clepsinoides Dugès, 1828 from Lake Biwa, Japan. A, Entire specimen in living state, lost after photographed. B, C, Transverse sections through proboscis anterior chamber; white arrowheads pointing to proboscis nerves. D, Sagittal section through the opening of the oesophagus–rhynchodaeum complex; black arrowheads pointing to cilia on ventral wall of oesophagus; anterior to the left. E, Magnification of D, showing sparse cilia on ventral wall of oesophagus, indicated by black arrowheads. F, Magnification of D; black arrowhead pointing to longitudinal muscle fibre along rhynchodaeum.G, Sagittal section near rhynchodaeal opening; anterior to the right. B, D, E, F, ICHUM 6272; C, ICHUM 6277; G, ICHUM 6273.