Gonaxis cf. percivali (Preston, 1913)

Muratov, Igor V., 2010, Terrestrial molluscs of Cabo Delgado and adjacent inland areas of north-eastern Mozambique, African Invertebrates 51 (2), pp. 255-255 : 271-272

Gonaxis cf. percivali (Preston, 1913)

Fig. 32

A few damaged shells found at two stations inland. Quite similar in size and proportions to Streptaxis percivali described by Preston (1913 b: 194, pl. 32, fig. “4” –

should be 5) from north-central Kenya (9.25×7.00 mm) and S. woodhousei Preston (1913 b: 194, pl. 32, fig. “5” – should be 4) from Uganda (9.5×7.0 mm). The numbers of the figures have been erroneously switched in the original descriptions. The transverse radial sculpture is coarser in woodhousei and the umbilicus is wider (although still narrow) in percivali . According to Germain (1923: 12) as well as Bequaert and Clench (1936: 269) these two are synonyms. Germain (1923: 12) even suggested that Gonaxis cavallii ( Pollonera, 1906) , with a much more open umbilicus, could be the same species. However, all shells from north-eastern Mozambique are smooth except for the minutely serrated suture and have the umbilicus completely sealed in all the adults. Thus the identification of these shells remains tentative until the range of variation in percivali , woodhousei and cavallii is re-evaluated.

Can easily be separated from all other (except the following) species in the area by the distorted shell. It is much larger than the following species.

Figures

Figs 30–38.Streptaxidae:(30) Edentulina affinis,33.4×17.6 mm,stn 5; (31) Taylorialeroyi, 14.4×21.0 mm, stn 5; (32) Gonaxis cf. percivali, 9.4×6.9 mm, stn 1; (33) G. denticulatus, 7.0×4.6 mm, stn 11; (34) Gulella sexdentata var. liederi, 9.4×4.8 mm, stn 1; (35) G. subhyalina, 6.5×2.3 mm, stn 1; (36) G. perissodonta, 3.2×1.5 mm, stn 7; (37) Gulella delgada sp. n., 4.0×1.8 mm, 1st syntype, stn 7; (38) Streptostele herma, 3.8×1.2 mm, stn 7. Scale bar 10 mm in Figs 30–31; 3 mm in Figs 32–34; 1 mm in Figs 35–38.