Cryptozona siamensis (Pfeiffer, 1856)

Sutcharit, Chirasak, Thach, Phanara, Chhuoy, Samol, Ngor, Peng Bun, Jeratthitikul, Ekgachai, Siriwut, Warut, Srisonchai, Ruttapon, Ng, Ting Hui, Pholyotha, Arthit, Jirapatrasilp, Parin & Panha, Somsak, 2020, Annotated checklist of the land snail fauna from southern Cambodia (Mollusca, Gastropoda), ZooKeys 948, pp. 1-46 : 1

Cryptozona siamensis (Pfeiffer, 1856) Fig. 4D

Helix siamensis Pfeiffer, 1856: 32. Type locality: Siam [Thailand].

Hemiplecta dichromatica Morlet, 1889: 124, 175, 176, pl. 6, fig. 2. Type locality: de Srakéo à Ang-Son (Siam) [Srakeo Province, Thailand].

Cryptozona siamensis : Inkhavilay et al. 2019: 75, 76, figs 35a, 56b.

Material examined.

Locality no. 4: CUMZ-CM147 (1 specimen in ethanol; Fig. 4D ). Locality no. 18: CUMZ-CM146 (2 shells). The snails were found to live on the ground among leaf litter.

Distribution.

Cambodia, Laos, Malaysia, Singapore and Thailand ( Tan et al. 2016, Inkhavilay et al. 2019).

Remarks.

This widespread species has recently been recorded from Singapore and Peninsular Malaysia ( Tan et al. 2016), Laos ( Inkhavilay et al. 2019) and Yunnan, China (C. Sutcharit, pers. obs.). In Thailand, C. siamensis is found throughout the country and the allozyme analysis by Prasankok and Panha (2011) indicates a surprisingly high level of genetic homogeneity among populations. This suggests that C. siamensis probably occupies almost all habitat types through accidental introduction or horticultural trade activities, and this species is especially abundant in human-modified landscapes.

The historical record of this species from Cambodia was probably under the name " Hemiplecta dichromatica Morlet, 1889" which was subsequently considered to be conspecific with this species ( Fischer and Dautzenberg 1904). In this survey, C. siamensis was found from a suburb of Krong Chhbar Mon (locality no. 4), in which its habitats are associated with human activities. In contrast, Q. weinkauffiana could be found commonly in both natural forest and anthropogenic habitats.

Figures

Figure 4. Living snails of A Haploptychius sp. B Quantula weinkauffiana (Crosse & Fischer, 1863) C Trochomorpha paviei (Morlet, 1885) D Cryptozona siamensis (Pfeiffer, 1856) E Hemiplecta distincta (Pfeiffer, 1850) F Cambodiparmarion doroshenkoi Kuznetsov & Kuzminykh, 1999 G Parmarion martensi Simroth, 1893 and H Durgella russeola (Morelet, 1865). All not to scale.