Gudeodiscus (Gudeodiscus?) infralevis (Gude, 1908)

Pall-Gergely, Barna, Hunyadi, Andras, Ablett, Jonathan, Lương, Hao Văn, Fred Naggs, & Asami, Takahiro, 2015, Systematics of the family Plectopylidae in Vietnam with additional information on Chinese taxa (Gastropoda, Pulmonata, Stylommatophora), ZooKeys 473, pp. 1-118 : 22-23

Taxon classification Animalia Stylommatophora Plectopylidae

Gudeodiscus (Gudeodiscus?) infralevis (Gude, 1908) Figures 3 D–E, 15 A–D

Plectopylis infralevis Gude 1908, Journal de Conchyliologie, 55: 345, 350, 352-353., Figs 3 a–e, Plate 7, Figs 4-6. ["Quang Huyen"].

Plectopylis soror Gude 1908, syn. n., Journal de Conchyliologie, 55: 355-357., Figs 5 a–e, Plate 7, Figs 10-12. ["Quang Huyen"].

Gudeodiscus infralevis , - Páll-Gergely & Hunyadi 2013, Archiv für Molluskenkunde, 142 (1): 8.

Gudeodiscus soror , - Páll-Gergely & Hunyadi 2013, Archiv für Molluskenkunde, 142 (1): 8.

Types examined.

Tonkin, Quang-Huyen, leg. Mansuy, MNHN 24604 (holotype of infralevis , Figure 3D); Tonkin, Quang-Huyen, leg. Mansuy, MNHN 24585 (holotype of soror , Figure 3E).

Diagnosis.

Shell small, solid, discoid, with elevated spire, relatively deep umbilicus; relatively thin apertural lip and rather parallel, thick, straight palatal plicae. See also under remarks.

Measurements

(in mm): D = 13.9, D = 6.7 ( soror holotype); D = 13.5, H = 6.6 ( infralevis holotype).

Differential diagnosis.

Our knowledge on the intraspecific variety of the species is very limited (see Remarks). It seems that the thick, rather horizontal palatal plicae, the strong basal sculpture and the elevated spire distinguishes the species from the similar species ( Gudeodiscus eroessi , Gudeodiscus multispira , Gudeodiscus soosi , Gudeodiscus yunnanensis , Gudeodiscus cyrtochilus and Gudeodiscus fischeri ). The shell and aperture shape suggest that the closest relatives are Gudeodiscus fischeri and Gudeodiscus suprafilaris (see comparisons under those species).

Intraspecific diversity.

Plectopylis infralevis and Plectopylis soror are considered as conspecific (see Remarks). Only the holotypes of these taxa are known, therefore our knowledge on the intraspecific variability is limited.

Distribution.

The type specimens of Plectopylis infralevis and Plectopylis soror (synonym of infralevis ) were collected in Quang Huyen (Quảng Uyên) (see Figure 39).

Remarks.

Only the holotypes of Plectopylis infralevis and Plectopylis soror are known. The notable differences between these two shells are the stronger sculpture, slightly shouldered body whorl and small apertural fold in soror . Additionally, there are three lamellae in infralevis versus only one in soror . The three vertical lamellae in the holotype of infralevis is possibly the result of abnormal development. No other species of Plectopylidae has three lamellae. Similar abnormal shells have been reported in Gudeodiscus giardi (see Gude 1908). Consequently, we do not know what the characteristic type of parietal lamellae in this species is (=one or two). The differences between the two specimens suggest only intraspecific variance. Unfortunately we have no freshly-collected material of these two forms, but because of the high similarity between the two holotypes and same type locality we here synonymise soror with infralevis . These two names were published in the same paper ( Gude 1908), but infralevis was described earlier in terms of page numbers.