Hunyadiscus Pall-Gergely

Pall-Gergely, Barna, Muratov, Igor V. & Asami, Takahiro, 2016, The family Plectopylidae (Gastropoda, Pulmonata) in Laos with the description of two new genera and a new species, ZooKeys 592, pp. 1-26 : 5

Taxon classification Animalia Pulmonata Plectopylidae

Hunyadiscus Pall-Gergely gen. n.

Type species.

Hunyadiscus saurini sp. n.

Content.

andersoni Blanford, 1869, saurini Páll-Gergely, sp. n.

Diagnosis.

Shell dextral, body whorl keeled or angulated; protoconch with spiral and radial lines, with the spirals being dominant; palatal plicae slightly sinuate; parietal wall with a single lamella and some additional plicae/denticles anteriorly and/or posteriorly. Internal anatomy unknown. See also Remarks.

Differential diagnosis.

Hunyadiscus gen. n. differs from all other plectopylid genera by the protoconch sculpture, which is characterized by both spiral and radial lines, the spirals being dominant. Moreover, all species of Gudeodiscus , Halongella and Naggsia gen. n. have a rounded body whorl, which is keeled in Hunyadiscus gen. n. The most similar genus to Hunyadiscus gen. n. is Sinicola , which also possess a keeled (shouldered) body whorl, and usually lacks the apertural fold. See also Table 1.

Etymology.

The genus is dedicated to András Hunyadi, Hungarian malacologist and shell collector, who first called the attention of the first author on the necessity of revising the family Plectopylidae . The name Hunyadiscus is the combination of the family name Hunyadi and discus (Latin: disc), which refers to the shape of the shells.

Distribution.

One species ( Hunyadiscus saurini sp. n.) inhabits southern part of Northern Laos (exact locality unknown), the other species ( Hunyadiscus andersoni ) lives in southern Kachin state (Myanmar), at the bordering Chinese region (Figure 15).

Remarks.

Many plectopylid species belonging to the genera Endoplon , Endothyrella , Gudeodiscus , Halongella , Plectopylis , Sicradiscus possess two parietal lamellae (anterior and posterior). Other species, however, possess only a single one. In most cases it is possible to decide that the single lamella is homologous with either the anterior or the posterior lamella, because there are “remains” of the other lamella. For example, in some Gudeodiscus species (e.g. Gudeodiscus multispira [ Möllendorff, 1883]), there are some small denticles in position of the anterior lamella, anterior to the well-developed, curved lamella. This indicates that the curved lamella is homologous with the posterior lamella. In contrast, in the genera Sicradiscus and Endothyrella , many species have small denticles on the posterior side of the single lamella. This suggests, that the single, well developed lamella is homologous with the anterior lamella ( Páll-Gergely and Asami 2016). Hunyadiscus andersoni also has two small denticles on the posterior side of the lamella, one above, one below. This suggests that the single lamella of Hunyadiscus andersoni is homologous with the anterior lamella. The single lamella of Hunyadiscus saurini sp. n. is, on the other hand, probably homologous with the posterior lamella, because it has a strongly curved shape, and has a lower plica positioned anteriorly, which is, when present, situated under the anterior lamella in Gudeodiscus species. These hypotheses suggest that the two species of Hunyadiscus have remarkably different parietal plication (Fig. 11).