Proxenetes segmentatus Den Hartog, 1966

Willems, Wim R., Sandberg, Maria I. & Jondelius, Ulf, 2007, First report on Rhabdocoela (Rhabditophora) from deep parts of Skagerrak, with the description of four new species, Zootaxa 1616, pp. 1-21 : 15-16

Proxenetes segmentatus Den Hartog, 1966

( Fig. 6 C–D)

Locality. Loc. 1.

Known distribution. Zeeland, Netherlands ( Den Hartog 1966)

Material. One individual studied alive and whole-mounted.

Description and remarks. The plump, wide and open stylet ( Fig. 6 D) is 58 µm long. The curved, tubular part and the surrounding mantle, showing several spines are 83 µm and 35 µm long respectively. The ducts of the bursal appendage ( Fig. 6 C) are 86 µm long and the proximal cuticular ring is 17 µm wide. No other hard parts are present. The detailed structure and the size of both hard parts fits well with the description of P. s e g - mentatus Den Hartog, 1965. However, Den Hartog (1966) mentions a slightly shorter bursal appendage, 60 µm long.

This species was found by Den Hartog (1966) in a shallow salt-marsh, whereas our specimen was collected at a depth of 116– 161 m.

Figures

FIGURE 6. Prognathorhynchus dubius A, general organisation (from a live individual). B, proboscis hook (from live individual; freehand drawing). Proxenetes segmentatus. C, bursal appendage (from a whole-mount). D, stylet (from a whole-mount). Utelga heinckei E – F, stylet hooks of two different individuals (from whole mounts).