Hypselostoma crossei Morlet, 1886

Figs 242 B, 244, 245, 246, 247, 248, 249, 250, 251

Hypselostoma crossei Morlet, 1886: 2–3.

Hypselostoma crossei — Möllendorff 1891: 338.

Hypselostoma crossei brevituba Möllendorff, 1901 b: 76 . syn. nov.

Hypselostoma crossei endodonta Möllendorff, 1901 b: 76 . syn. nov.

Hypselostoma brevituba — Fischer and Dautzenberg 1904: 408.

Hypselostoma crossei endodonta — Fischer and Dautzenberg 1904: 408.

Gyliotrachela crossei — Pilsbry 1917: 215–216; van Benthem Jutting 1950: 44; Inkhavilay et al. 2019: 147, fig. 17 I; Thompson and Upatham 1997: 233.

Gyliotrachela crossei brevituba — Pilsbry 1917: 217, pl. 36, figs 9–13; van Benthem Jutting 1950: 45; Zilch 1984: 165; Schileyko 2011: 3.

Boysidia (Bensonella) xingyinensis Guo, Zhou & Luo, 2006: 541–542 (Chinese description), 542–543 (English description), figs 1–4. syn. nov.

Gyliotrachela crossei endodonta — Pilsbry 1917: 217; van Benthem Jutting 1950: 45; Zilch 1984: 165; Schileyko 2011: 3.

Boysidia (Bensonella) tianxingqiaoensis Luo, Chen & Zhang, 2000: 147 (Chinese description), 150 (English description), figs 1–4. syn. nov.

Boysidia (Bensonella) tianxingqiaoensis — Chen and Zhang 2002: 693.

Gyliotrachela crossei crossei — Schileyko 2011: 3.

Gyliotrachela plesiolopa Inkhavilay & Panha in Inkhavilay et al. 2016: 222, figs 1, 3 D – F, 4 D. syn. nov.

Gyliotrachela plesiolopa — Inkhavilay et al. 2019: 60, fig. 26 D.

Boysidia tianxingqiaoensis — Dumrongrojwattana and Assawawattagee 2018: 216.

Boysidia xingyinensis — Dumrongrojwattana and Assawawttagee 2018: 216.

Gyliotrachela tianxingqiaoensis – Gojšina et al. 2022: 132, figs 2–5; Tongkerd et al. 2024: 182, fig. 13 N.

Type material examined.

Vietnam • syntype of H. crossei crossei; coll. Morlet; MNHN -IM-2000-35155 • lectotype of G. crossei brevituba; ex. coll. Fruhstorfer; coll. Möllendorff; SMF 4582 • lectotype of G. crossei endodonta; ex. coll. Fruhstorfer; coll. Möllendorff; SMF 4584 . China • holotype of B. tianxingqiaoensis; 13 Aug. 1997; D. - N. Chen leg.; IZCAS 025075 • holotype of B. xingyinensis; 02 Oct. 2004; Guo Y. - H, Zhou W. - C., Luo T. - C. leg.; IZCAS 069205 . Laos • 2 paratypes of G. plesiolopa; from the type locality; ex. coll. S. Panha; SMF 357824 .

Additional material examined.

Vietnam • 1 shell; Cao Bang Province, wet limestone wall; Jul. 2006.; M. Calo leg.; coll. PGB • 1 shell; Ninh Binh Province, Ninh Binh, Hoa Lu Temple; 20°15.738'N, 105°57.886'E; 8 m a. s. l.; 01 Oct. 2009; Hemmen leg; coll. PGB • 1 shell; Hoa Binh Province, ca 15 km rd. Tang Dao to Co Luong (rd # 15 left side); 20°35.951'N, 105°01.905'E; 16 Oct. 2011.; Hemmen leg; coll. PGB • 5 shells; Quang Ninh Province, Ha Long Bay area, Tien Ong Cave on Hang Trai Island; 20°48.96'N, 107°07.33'E; 6 Sept. 2003.; Hemmen leg; coll. PGB • 1 shell; Quang Ninh Province, near Dau Go Isl., Halong Bay; 20°53.853'N, 107°00.825'E; 2 m a. s. l.; 18 Nov. 2005; J. U. Otani leg.; coll. PGB • 23 shells; Ninh Binh Province, Nho Quan District, Cuc Phuong N. P., near kiosk at entrance to Cave of the prehistoric man (Dong Nguoi Xua); 20°17.613'N, 105°40.063'E; 247 m a. s. l.; 12 Apr. 2007; K. Okubo & J. U. Otani leg.; coll. PGB • 2 shells; Quang Ninh Province, Halong Bay area, Hang Trai Id., Tieng Ong cave; 20°48.96'N, 107°07.33'E; Hemmen leg; coll. PGB • 15 shells; Hai Phong city, Cat Ba island, Gia Luan Commune; 20°51.402'N, 106°58.961'E; 4 m a. s. l.; 18 Nov. 2005; J. U. Otani leg.; Coll, PGB • 3 shells; Cao Bang Province, Pac Rao, 300 m from junction to Xa Canh Tien towards Trung Khanh, right side of the road; 22°49.385'N, 106°30.742'E; 530 m a. s. l.; 28 May 2012; A. Hunyadi leg.; coll. HA • 2 shells; Lang Son Province, Lang Son, NNE side of Nui Vong Phu; 21°51.183'N, 106°44.950'E; 11 Nov. 2011; A. Hunyadi leg.; coll. HA • 1 shell; Lang Son Province, north of Chi Lang, pass along the path (north of Đong Banh); 21°34.945'N, 106°30.567'E; 75 m a. s. l.; 13 Nov. 2011; A. Hunyadi leg.; coll. HA • 5 shells; Lang Son, vicinity of Chua Tam Thanh; 21°51.353'N, 106°44.809'E; 265 m a. s. l.; 21 Feb. 2020; A. Hunyadi leg.; coll. HA • 1 shell; Thai Nguyen Province, Cho Chu, rock wall at the northeastern part of the village; 21°54.613'N, 105°39.195'E; 90 m a. s. l.; 21 Nov. 2011; A. Hunyadi leg.; coll. HA • 34 shells: Lang Son Province, Lang Son, Thanh Nha Mac, southern group of rocks; 21°51.358'N, 106°45.035'E; 295 m a. s. l.; 26 May 2012; leg. A. Hunyadi; coll. HA • 7 shells; Lang Son Province, Huu Lung district, Minh Tien, Cau Cheo Minh Tien, southern side of the bridge; 21°33.605'N, 106°17.427'E; 20 m a. s. l.; 20 Feb. 2020; A. Hunyadi leg.; coll. HA • 7 shells; Thanh Hoa Province, north of Thanh Hoa, Ham Rong Eny, Đong Tien Son; 19°51.108'N, 105°46.783'E; 35 m a. s. l.; 24 Nov. 2011; A. Hunyadi leg.; coll. HA • 60 shells; Hoa Binh Province, Tan Lac district, Quy Hau, 1300 m west on road no. 6, rock wall; 20.63222°N, 105.26955°E; 150 m a. s. l.; 11 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA • 54 shells; Son La Province, 32.2 km northwest from centre of Son La towards Tuan Giao, Phong Lang, Tong Lanh, northeastern part of the village; 21°26.283'N, 103°43.965'E; 550 m a. s. l.; 07 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA • 180 shells; Son La Province, Quynh Nhai district, 20 km north from junction of Thuan Chau, Chieng Khoang, cave above the village; 21°33.441'N, 103°40.909'E; 315 m a. s. l.; 07 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA • 155 shells; Thanh Hoa Province, Quan Hoa district, Khu di tich Hang Ma, Song Luong gorge; 20°23.888'N, 105°4.016'E; 100 m a. s. l.; 12 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA • 386 shells; Thanh Hoa Province, 3.6 km northwest from centre of Ngoc Lac, Lang Sat, 600 m north on the road no 15, under rock wall; 20°5.897'N, 105°21.578'E; 55 m a. s. l.; 13 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA • 51 shells; Hoa Binh Province, Mai Chau, 550 m west of Cho Mai Chau, stream bank; 20.66029°N, 105.07804°E; 265 m a. s. l.; 11 Feb. 2020; A. Hunyadi, H. V. Luong, J. U. Otani & S. V. Pham leg.; coll. HA . China • 1 shell; Guangxi, Guigang Shi, Guzhang Xiang, Chuanshancun, road leading to north, limestone rock wall on the east; 23°20.865'N, 109°19.169'E; 150 m a. s. l.; 10 Sept. 2009; A. Hunyadi leg.; coll. HA • 17 shells; Guangxi, Chongzuo Shi, Longzhou Xian, Wude Xiang, Banxintun, vicinity of the junction; 22°35.239'N, 106°46.096'E; 350 m a. s. l.; 24 Sept. 2013; A. Hunyadi & M. Szekeres leg.; coll. HA • 2 shells; Yunnan, Yuxi shi, Chengjiang Xian, Luchong Ziran Fengjingqu, under Liushanting; 24°33.842'N, 102°50.614'E; 1778 m a. s. l.; 18 Mar. 2011; A. Hunyadi leg.; coll. HA • 2 shells; Guangxi, Guigang Shi, Guzhang Xiang, rocks above Chuanshancun; 23°21.056'N, 109°19.247'E; 200 m a. s. l.; 10 Sept. 2009; A. Hunyadi leg.; coll. HA • 9 shells; Guangxi, Laibin Shi, Wuxuan Xian, Wuxuan Tongling Zhen road, north of Yagangcun, rock wall; 23°29.827'N, 109°38.534'E; 21 Sept. 2013; A. Hunyadi & M. Szekeres leg.; coll. HA • 3 shells; Guangxi, Hechi Shi, Du an Yaozu Zizhixian, Gaoling Xiang, 2 km west from Dingfucun; 24°03.197'N, 108°01.290'E; 320 m a. s. l.; 10 Aug. 2009; A. Hunyadi leg.; coll. HA • 17 shells; Yunnan, Wenshan Zhuangzu Miaozu Zizhizhou, Guangnan Xian, Babao Zhen, southeastern edge of Babao; 23°44.682'N, 105°24.875'E; 1130 m; 24 Mar. 2011; A. Hunyadi leg.; coll. HA • 33 shells; Guangxi, Laibin Shi, Wuxuan Xian, Wuxuan Tongling Zhen road, west from Yagangcun, rocks; 23°29.151'N, 109°38.375'E; 80 m a. s. l.; 21 Sep 2013; A. Hunyadi & M. Szekeres leg.; coll. HA • 11 shells; Guangxi, Bose Shi, Leye Xian, southern edge of Molicun, left bank of Buliu He; 24°39.436'N, 106°43.245'E; 540 m a. s. l.; 08 Sep. 2013; A. Hunyadi & M. Szekeres leg.; coll. HA • 17 shells; Guangxi, Bose Shi, Lingyun Xian, Xiajia Xiang, southeastern edge of Xiajia, rock wall above the graves; 24°17.508'N, 106°38.376'E; 440 m a. s. l.; 22 Oct. 2009; A. Hunyadi leg.; coll. HA • 5 shells; village across from Yangchangshilin, Moyangzhen, Luodianxian, Guizhousheng; 25°32′39″N, 106°49′39.14″E; 908 m a. s. l.; T. Ishibe, K. Okubo, J. U. Otani leg.; coll. PGB • 4 shells; same data as previous; coll. PGB • 9 shells; Daxiaojingfengjingqu, Moyangzhen, Lodianxian, Guizhousheng; 25°33′39″N, 106°51′39″E; 450 m a. s. l.; T. Ishibe, K. Okubo, J. U. Otani leg.; coll. PGB • 8 shells; same data as previous; T. Ishibe, K. Okubo, J. U. Otani leg.; coll. PGB • 1 shell; Xianshanyuan, Shuangqiao-zhen, Wuming-xian, Guangxi Zhuanzu Zizhiou; 23°02.08015'N, 108°17.68551'E; 177 m a. s. l.; Ohai leg.; coll. PGB .

Type localities.

“ Tonkin ” (Montagne de ľÉléphant, Tonkin, Vietnam) ( H. crossei crossei); “ Lang-son ” (Tonkin, N Vietnam) ( H. crossei brevituba); “ Lang-son ” (Tonkin, N Vietnam) ( H. crossei endodonta); “ collected from Tianxingqiao Town, Zhenning Bouyeizu Miaozu Zizhixian, Guizhou Province (26°N, 105°07'E), Guizhou Province ”, China ( G. tianxingqiaoensis); “ collected from Nahui Town, Xingyi County (25°1'N, 104°8'E), Guizhou Province, China ” ( G. xingyinensis); “ Limestone outcrop in Nawit Village, Viengxay District, Houaphane Province, Laos (20°22'37.3"N, 104°16'43.2"E), 695 m amsl ” ( G. plesiolopa).

Differential diagnosis.

This species differs from all its congeners by the combination of the dark brown shell, which is moderately umbilicate, numerous and variable apertural barriers, almost smooth shell surface (pasty), as well as the absence of the spiral striation.

Distribution.

This species is known from a wide area covering China, N Vietnam, Myanmar, and Laos (from where it is known as G. plesiolopa).

Remarks.

The examination of type specimens of H. crossei brevituba and H. crossei endodonta and numerous additional samples of H. crossei, led us to the conclusion that this species is very variable regarding the appearance of the last whorl and also regarding barrier numbers, as was also observed by Pilsbry (1917). These were the characters used to describe the subspecies and there are no reasons to support their distinctness. Gyliotrachela plesiolopa, G. xingyinensis and G. tianxingqiaoensis are junior synonyms of this species since no major morphological differences were observed. The latter two are originally described in exactly the same way, using exactly the same sentences, and are not compared mutually (or to H. crossei) but to other very distant species (Luo et al. 2000; Guo et al. 2006). Inkhavilay et al. (2016) pointed out that G. plesiolopa has fewer whorls (four) than H. crossei (five). However, this is not true due to the fact that we examined the types of the nominotypical subspecies of H. crossei and the other two described subspecies all of which showed between 3.5–4 whorls. According to them, H. crossei is also larger, but there is a clear continuum in size variation up to 1 mm. Therefore, we do not consider this character as relevant.