Olisthanella opistomiformis Nasonov, 1924

(Figure 7)

Synonyms: Krumbachia opisthoformis Ruebush 1938

Locality. Permanent spring in Kaukab, Lower Galilee.

Material. Squash preparations, photographs and two sagittally-sectioned individuals deposited in the Department of Zoology at Tel Aviv University, Israel, Catalogue Number VR-25078 and VR-25079.

Morphological remarks. Contrary to the European specimens, the Israeli population shows rhabditetracts (“Stäbchenstrassen”).

Ecological features. Olisthanella opistomiformis is an inhabitant of pools and swamps with humus-rich bottoms. In Israel, it was found in a permanent water source, Kaubab spring (April 2002) (TABLE 1).

Olisthanella opistomiformis is reported from Europe and Brazil, although the species from Brazil was described by Marcus (1946) as Olisthanella parva . A review of the different descriptions of this species is necessary to determine a reliable distribution for O. opistomiformis . We consider O. opistomiformis to be distributed only in Europe and adjacent areas, as well as Israel.