Miscellanea Zoologica Hungarica 11. 1997 (Budapest, 1997)

Nesemann, H.: Rediscovery of the leech genus Ancyrobdella (Hirudinea, Glossiphoniidae)

Material: Japan, 57 specimens from four localities, Honshu: Uji Gawa (effluent of the Biwa-Ko) near Otsu, 23. Oct. 1994, 15 spec. (6 in Coll. HNHM); Katsura Gawa in Arashiyama, 31. Oct. 1994, 18 spec. (8 in Coll. HNHM); Hozu Gawa near Hozukyo, 2. Nov. 1994, 10 spec. (4 in Coll. HNHM); Shikoku: Ushiro Gawa near Nakamura, 26. Oct. 1994, 15 spec. (6 in Coll. HNHM), all leg. K. M. Polanec & H. Nesemann. Description: Small oval leeches, the preserved specimens reach up to 7-14 mm body length (Hozu Gawa 14 mm). The head is slightly bulbous and stretched forward. The cranial sucker is small and ring-shaped, prominent folds are lacking. The mouth pore is placed centrally near the middle of the cranial sucker. The head bears two pairs of small eyes. The first pair and the second pair are similar in size. The length of the proboscis reaches up to 1/6 of the total body length and bears three hook-like prominences. The crop has seven pairs of caeca. The genital pores are separated by two annuli. The male gonopore is in the furrow XIa3/XIIal, the female in XIIa2/a3. Living animals are always unicoloured without any dark pigmentation. The colour is basically pale green, greenish-blue to grey or reddish with filled crop caeca. The body consistence of living specimens is cartilaginous. Observing the leech in the field with the naked eye, A. smaragdina bears a resemblance to the European Glossiphonia paludosa. It differs slightly only by the form of the head and praeclitellar region, which is more slender and elongated than in G paludosa. The pharynx of European species of the genus Glossiphonia (sensu Sawyer 1986: 654) was compared with that of A. smaragdina (Figs 6-7). The results, presented in the figures 910 with the example of Glossiphonia complanata (Linnaeus, 1758) show a proboscis, which is typical for all of the investigated species (G. complanata, G. verrucata (Fr. Midler, 1844), G. concolor (Apathy, 1888), G. paludosa (Carena, 1824) and G. nebulosa Kalbe, 1964). The anterior tip of the proboscis of Glossiphonia spp. always bears numerous radially arranged folds. Based on the hitherto known information Ancyrobdella seems to be restricted to the Japanese islands. Figs 9-10. Glossiphonia complanata, Traisen at St. Pölten, Austria; 9 = Anterior tip of the proboscis with radially arranged folds; 10 = Dorsal view of the head region with completely everted proboscis