Hypselostoma adela (F. G. Thompson & Upatham, 1997) comb. nov.

Figs 111 A, 112, 113, 154

Gyliotrachela adela Thompson & Upatham, 1997: 234–235, figs 44–47.

Gyliotrachela adela — Tongkerd et al. 2004: 143, fig. 2; Panha and Burch 2008: 65–66, fig. 57; Dumrongrojwattana and Wongkamhaeng 2024: 323, fig. 8.

Type material examined.

Thailand • holotype; 03 June 1987; F. G. Thompson leg.; UF 00113508; 4 paratypes; from the type locality; 03 June 1987; F. G. Thompson leg.; UF 00113509 .

Additional material examined.

Thailand-South • 16 shells; Suratthani Province, 28.4 km E Surat Thani, 19 km S Hwy. 401, dry, scrubby evergreen forest, leaf litter, rocks, boulders; 9.15°N, 99.6°E; 40 m a. s. l.; 19 Apr. 1988; K. Auffenberg leg.; locality code KA-0675; UF 591322 • 15 shells; Suratthani Province, limestone outcrop along Hwy. 401, 2.7 km W junc Hwys. 4142 & 401; 9°10'N, 99°40'E; 90 m a. s. l.; 19 Apr. 1988; K. Auffenberg leg.; locality code KA-0673; UF 591323 • 2 shells; Suratthani Province, 15.3 km NE Ban Na San off road to Tha Rom Yen National Park; 8°53'N, 99°26'E; 40 m a. s. l.; 20 Apr. 1988; K. Auffenberg leg.; locality code KA-0678; UF 345389 • 5 shells; Suratthani Province, 13.8 km SE Don Sak, 5 km SW Hwy. 4142; 9°18'N, 99°43'E; 50 m a. s. l.; 14 Apr. 1988; K. Auffenberg leg.; locality code KA-0670; UF 345284 • 1 shell; Suratthani Province, 1 km NE of Na San, 100 m limestone mountain; 8.812°N, 99.382°E; 20 June 1987; F. G. Thompson leg.; locality code FGT-4309; UF 529617 • 35 shells; Suratthani Province, Hwy. 401, 2.7 km W junction Hwy. 4142 and 401, evergreen forest on rocky hillside, below cliff, base of cliff; 9°10'N, 99°40'E; 90 m a. s. l.; 19 Apr. 1988; K. Auffenberg leg.; locality code KA-0674; UF 345331 • 3 shells; Suratthani Province, 4.5 km S Don Sak, E side of Hwy. 4142, evergreen forest, limestone outcrop, base of cliff; 9°18'N, 99°42'E; 40 m a. s. l.; 18 Apr. 1988; K. Auffenberg leg.; locality code KA-0672; UF 345302 • 5 shells; Suratthani Province, 15.3 km NE Ban Na San off road to Thi Rom Yen National Park; 8°53'N, 99°26'E; 40 m a. s. l.; 20 Apr. 1988; K. Auffenberg leg.; locality code KA-0678; UF 591320 • 12 shells; Suratthani Province, 13.8 km SE Don Sak, 5 km SW Hwy. 4142; 9°18'N, 99°43'E; 50 m a. s. l.; 17 Apr. 1988; K. Auffenberg leg.; locality code KA-0669; UF 345277 • 9 shells; Suratthani Province, 15.3 km NE Ban Na San off road to Tha Rom Yen National Park; 8°53'N, 99°26'E; 40 m a. s. l.; 20 Apr. 1988; K. Auffenberg leg.; locality code KA-0679; UF 345397 • 16 shells; Suratthani Province, 28.4 km E Surat Thani, 1.9 km S Hwy. 401, dry, scrubby evergreen forest, leaf litter, rocks, boulders; 9.15°N, 99.6°E; 40 m a. s. l.; 19 Apr. 1988; K. Auffenberg leg.; locality code KA-0675; UF 436269 • 2 shells; Suratthani Province, limestone hill (with monastery) left side off rd. # 4009 (~ 11 km N of Waing Sa); 08°41.590'N, 099°22.689'E; ex. coll. Hemmen, Wiesbaden; coll. PGB • 8 shells; Nakhon Si Thammarat Province, 15.6 km SE Don Sak, 1 km SW Hwy. 4142; 9°17'N, 99°46'E; 50 m a. s. l.; 15 Apr. 1988; K. Auffenberg leg.; locality code KA-0667; UF 345253 • 16 shells; Nakhon Sri Thammarat Province, 15.6 km SE Don Sak, 1 km SW Hwy. 4142; 9°17'N, 99°46'E; 50 m a. s. l.; 17 Apr. 1988; K. Auffenberg leg.; locality code KA-0668; UF 345258 • 2 shells; Nakhon Sri Thammarat Province, limestone hill right off road # 4142 ca km 38.2 (road Khanom-Don Sak); Mar. 2000; ex. coll. Hemmen, Wiesbaden; coll. PGB • 4 shells; Krabi Province, Phi Phi islands, Phi Phi Don island, climbing rock above the western end of the beach in Ton Sai Bay, at the base of limestone rocks in the forest; 7°44.063'N, 98°45.947'E; 50 m a. s. l.; Mar. 2010; A. Reischütz leg; coll. REI • 1 shell; Phattalung Province, Khao Ok Thalu, rock wall; 07°37.506'N, 100°05.330'E; 19 Feb. 2015; A. Hunyadi leg.; coll. HA • 1 shell; Phatthalung Province, Khao Pu-Khao Ya Nat. Parl, Si Banphot district, ca 6 km NNW of Taphaen, 7°40.738'N, 99°50.822'E; 24 Feb. 2023; A. Hunyadi, K. Okubo & J. U. Otani leg.; coll. HA • 1 shell; Songkhla Province, 31.3 km NW Hat Yai, 1.2 km W of Hwy. 43; 7°10'N, 100°16'E; 80 m a. s. l.; 08 Apr. 1988; K. Auffenberg leg.; locality code KA-0636 B; UF 344945. Malaysia • 3 shells; Pahang, Bandar Pusat Jengka, west 15 km, Hutan Lipur Gunung Senyum; 03°41.862'N, 102°25.980'E; 85 m a. s. l.; 23 Jan. 2013; A. Hunyadi leg.; coll. HA .

Type locality.

“ Thailand, Surat Thani Province, box canyon in limestone range 6 km south of Na San; 100 m altitude (08°39.6'N, 99°23.9'E) ”.

Differential diagnosis.

This species is not similar to any other congener and is unique due to the combination of the following characters: small size, yellowish shell, spirally striated teleoconch with descending detached last whorl and aperture equipped with several equally developed barriers (without smaller ones). See under H. cucumense .

Distribution.

This species in known from several localities in Thailand and one in Peninsular Malaysia. Our record from Malaysia is the first record of this species in the country.

Remarks.

Apertural barriers were constant in number in all the specimens examined. We have examined the material from northern Thailand hosted in UF with the following data: 1 shell; Mae Hong Song Province, Tham Lod Cave, 1.5 km SE Ban Tham Lod Village, 6 km N Sappong on Road 1095; 19°34'N, 98°9'E; 720 m a. s. l.; 19 Mar. 1988; K. Auffenberg leg.; locality code KA-0576; UF 591321; 7 shells; Mae Hong Song Province, Tham Lod Cave, 1.5 km SE Ban Tham Lod Village, 6 km N Sappong on Road 1095; 19°34'N, 98°9'E; 720 m a. s. l.; 19 Mar. 1988; K. Auffenberg leg.; locality code KA-0674; UF 345523. Since these localities are quite far from the actual distribution area of this species, we believe that these samples were mislabelled and that this species actually does not occur in Mae Hong Son Province.