Hypselostoma modestum (van Benthem Jutting, 1950) comb. nov.

Figs 224 E, 231, 241

Gyliotrachela modesta van Benthem Jutting, 1950: 31–32, fig. 18.

Gyliotrachela modesta — van Benthem Jutting 1950: 46; Davison and Kiew 1990: 25; Maassen 2001: 76.

Type material examined.

Malaysia • 2 paratypes; from the type locality; 1939; Raffles Museum, Singapore ex. coll.; RMNH.Moll.137148 .

Type locality.

“ Gua Musang, Kelantan ”, Malaysia.

Differential diagnosis.

This species is very similar to H. emergens from which it differs in its narrower last whorl (but also the entire shell) which is also more detached and protruding. The keel on the last whorl is also stronger in H. emergens (best seen in the lateral view). Hypselostoma frequens has a narrower umbilicus and more enlarged last whorl when compared to the previous ones, which makes the shell less slender. See also under H. muaklekense and H. burchi .

Distribution.

This species is known only from the type locality.