Phaedusa Adams & Adams, 1855

Dedov, Ivailo, Vu, Quang Manh, Le, Chi Toan, Tra, Van Tung & Szekeres, Miklos, 2025, The Clausiliidae (Gastropoda: Stylommatophora) of the Tam Dao National Park, Vietnam, Acta Zoologica Bulgarica 77 (1), pp. 41-48 : 43

Genus Phaedusa Adams & Adams, 1855

Phaedusa Adams & Adams 1855: 205

Type species: Clausilia corticina Pfeiffer, 1842 , by subsequent designation (Martens in Albers 1860).

Phaedusa dichroa ( Bavay & Dautzenberg, 1899)

( Fig. 1E)

Clausilia dichroa Bavay & Dautzenberg 1899: 287 , pl. 12, fig. 8

Type locality: Bac Kan .

Locality data: Tam Dao N. P., rain forest, 800–900 m, leg. A. Napolov 1998; Tam Dao N. P. (21.4553°N 105.6386°E), leg. Luong Van Hao 2006.

Distribution: Bac Kan, Lang Son, Vinh Phuc, Son La and Ninh Binh Provinces.

Habitat: Undisturbed forests.

Remark: This species is known only from a few localities in Northern Vietnam.

Phaedusa lypra (Mabille, 1887)

( Fig. 1F)

Clausilia lypra Mabille 1887b: 117

Type locality: “ Tonkin ” .

Locality data: Tam Dao N. P., rain forest, 800–900 m, leg. A. Napolov 1998.

Distribution: This species is known to occur in eastern India (Manipur State), Myanmar (Shan State and Mandalay Region), Thailand (Tak Province), southern China (Yunnan and Guangxi Provinces) and large parts of Northern Vietnam (Ha Giang, Cao Bang, Bac Kan, Lang Son, Thai Nguyen, Vinh Phuc, Son La, Thanh Hoa and Ninh Binh Provinces).

Habitat: Forests and cliff vegetation, as well as an- thropogenic environments.

Remark: Phaedusa lypra is one of the most widely distributed Asiatic clausiliids. Its local forms show considerable variation in size and sculpture ( Szekeres et al. 2021).

Phaedusa paviei ( Morlet, 1892)

( Fig. 1G)

Clausilia paviei Morlet 1892: 319 , pl. 7, fig. 1

Type locality: Muong Lay (Dien Bien Province) .

Locality data: Tam Dao N. P., rain forest, 800–900 m, leg. A. Napolov 1998.

Distribution: Hanoi Municipality and Dien Bien, Lai Chau, Lao Cai, Tuyen Quang, Bac Kan, Lang Son, Vinh Phuc, Son La and Hoa Binh Provinces.

Habitat: Forests, cliff vegetation and anthropogenic environments.

Remark: So far, all the known localities of this species are in Vietnam. However, its range may extend to north-eastern Laos and to Yunnan Province ( China).

Phaedusa phongthoensis Loosjes & Loosjes-van Bemmel, 1949

( Fig. 1H)

Phaedusa (Phaedusa) phongthoensis Loosjes & Loosjes-van Bemmel, 1949: 31 , figs 1–3, pl. 4

Type locality: Phong Tho (Lai Chau Province) .

Locality data: Tam Dao N. P. ( Hoang et al. 2012).

Distribution: Except for the Tam Dao record, all the known localities of P. phongthoensis are in Lai Chau and Lao Cai Provinces.

Habitat: Unknown.

Remark: The Tam Dao locality reported by Hoang et al. (2012) is quite far from the few other occurrences of this species in the most northwestern provinces of Vietnam. This record needs confirmation; because, as its description points out ( Loosjes & Loosjes-Van Bemmel 1949), Phaedusa phongthoensis is easily confused with P. paviei .

Phaedusa stenothyra Möllendorff, 1901

( Fig. 1I)

Phaedusa (Pseudonenia) stenothyra Möllendorff 1901: 116

Type locality: Cai Bau Island (Quang Ninh Province) .

Locality data: Tam Dao N. P. ( Hoang et al. 2012).

Distribution: Lang Son, Vinh Phuc, Quang Ninh, Hoa Binh and Ninh Binh Provinces.

Habitat: Cliff vegetation.

Remarks: This species is endemic to eastern regions of Northern Vietnam.