Gyraulus, Charpentier, 1837

Appleton, C. C. & Miranda, N. A. F., 2015, Two Asian freshwater snails newly introduced into South Africa and an analysis of alien species reported to date, African Invertebrates 56 (1), pp. 1-1 : 7-8

Key to species of Gyraulus in South Africa

One of the two indigenous species of Gyraulus in South Africa, G. connollyi is endemic to the central and southern parts of the country while the other, G. costulatus , is widespread across Africa (Brown 1994). Gyraulus chinensis may be separated from these two indigenous species by means of the following key:

1 Shell distinctly ribbed, shoulder with an angular carina ............ costulatus (Krauss)

– Shell not distinctly ribbed, shoulder rounded .........................................................2

2 Pigmentation of head, tentacles and mantle roof of pale spots and blotches, flatness index of whorl consistently below 3.0, prostate gland with 12 or more lobes of uniform length and arrangement, preputium usually longer than penis sheath ........ ................................................................................. connollyi Brown & Van Eeden

– Pigmentation of head, tentacles and mantle roof of conspicuous dark spots and blotches, flatness index of whorl between 1.9 and 4.0, prostate gland with fewer than 12 lobes, lobes of variable length and arrangement, preputium usually shorter than penis sheath ....................................................................... chinensis (Dunker)