Macrostomum

Schockaert, Ernest R., 2014, Marine Macrostomorpha (Platyhelminthes, Rhabditophora) from the Algarve (Southern Portugal), Zootaxa 3872 (5), pp. 577-590 : 579

Macrostomum species 2

Fig. 1 B

Localities in the Algarve. Faro ( Portugal), Ria Formosa, beach in front of the fishermen’s houses close to the Ramalhete research facilities of the University of the Algarve. Low mid-littoral, medium-grain sand with the reduced zone about 5 cm deep (37° 00.283 N, 7° 58.005 W; 7 October 2013).

Material. One whole mount (HU nr. VI.3.18).

The animal is less than 1 mm in the whole mount, with eyes. The total length of the stylet is 36 µm (28 µm measured along line b) and its proximal diameter is 13 µm. At about 24 µm from the proximal rim, the stylet is only 2 µm wide, where it makes a bend of 90° to ends sharply 13 µm further. This terminal spine spirals slightly in a counter-clockwise direction. The opening of the stylet was not seen. The proximal rim is reflected at one side (artefact?).

The length of the stylet of this species falls within the range of the stylet size of M. hystricinum (see above), though the proximal opening is somewhat narrower (length being twice the diameter), and the terminal part spirals. To the best of my knowledge, only M. spirale Ax, 1956 has a twisted end, but its stylet is over 120 µm long.