Image dataset: Freshwater leeches (Hirudinida: Glossiphoniidae) from Tibet collected by P.K. Kozlov's expedition in 1900-1901

This dataset is a supplement to our review paper entitled "Taxonomic diversity of leeches on the world's highest mountain ranges and plateaus" (Bolotov et al. 2025 in Zool. J. Linn. Soc.; https://doi.org/10.1093/zoolinnean/zlaf051). It contains photographs of historical specimens of three glossiphoiniid leech species, that is, Alboglossiphonia cf. szechuanensis (Chen, 1959), Theromyzon maculosum (Rathke, 1862), and Th. mollissimum (Grube, 1871), from the Tibetan Plateau (catalogue numbers: ZIN 1-‘Gl-heteroclita’; ZIN 14/44093; and ZIN 13/44092, respectively). The samples were collected in 1900-1901 by P.K. Kozlov's expedition to Mongolia and Tibet (Kozlov 1905, 1906; Andreev and Yusupova 2018). These leeches were initially processed by Plotnikov (1907) but all the species were incorrectly identified (see below). The three lots from Tibet were re-examined and photographed by us using a stereomicroscope Nikon SMZ 25 with a Nikon DS-Ri2 digital camera (Nikon Corporation, Minato, Tokyo, Japan). Large leech specimens were photographed using a Canon EOS R6 Mark II camera with a Canon EF-S 60 mm f/2.8 Macro USM lens (Canon Inc., Shimomaruko, Ota, Tokyo, Japan). The specimens are deposited in the Zoological Institute of the Russian Academy of Sciences [abbreviation: ZIN], Saint Petersburg, Russia.

HISTORICAL SPECIMEN PHOTOS (ZIN collection; by Tatyana A. Eliseeva)
D = dorsal view; V = ventral view

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(1) Alboglossiphonia cf. szechuanensis (Chen, 1959)
= Glossosiphonia heteroclita Plotnikov (1907): 135 [partim; identification error]
Lot ZIN 1-'Gl-heteroclita', labelled: “[Swamp spring], Dza-Chu Valley (Blue River basin), 12,100' a.s.l., [late July – mid-August 1900], Tibetan Expedition, [Kaznakov leg.]” [China: swamp spring, Zha Chu River valley, 33.0037°N, 96.9907°E, approx. 3,700 m alt., Yangtze River basin, Qinghai, August 1900, collected by P.K. Kozlov's expedition to Mongolia and Tibet, Kaznakov leg.] (5 adult specimens; all illustrated here)
Image files (25 photos):
- sample label: Alb_sze ZIN 1_label.JPG
- specimen 1 [adult]: Alb_sze ZIN 1_01 head dorsal.jpg; Alb_sze ZIN 1_01 head ventral.jpg; Alb_sze ZIN 1_01 specimen dorsal.jpg; Alb_sze ZIN 1_01 specimen ventral.jpg
- specimen 2 [adult]: Alb_sze ZIN 1_02 head dorsal.jpg; Alb_sze ZIN 1_02 head ventral.jpg; Alb_sze ZIN 1_02 specimen dorsal.jpg; Alb_sze ZIN 1_02 specimen ventral.jpg
- specimen 3 [adult]: Alb_sze ZIN 1_03 head dorsal.jpg; Alb_sze ZIN 1_03 head ventral.jpg; Alb_sze ZIN 1_03 specimen dorsal.jpg; Alb_sze ZIN 1_03 specimen ventral.jpg
- specimen 4 [adult]: Alb_sze ZIN 1_04 head dorsal 1.jpg; Alb_sze ZIN 1_04 head dorsal 2.jpg; Alb_sze ZIN 1_04 head ventral.jpg; Alb_sze ZIN 1_04 specimen dorsal 1.jpg; Alb_sze ZIN 1_04 specimen dorsal 2.jpg; Alb_sze ZIN 1_04 specimen ventral 1.jpg; Alb_sze ZIN 1_04 specimen ventral 2.jpg
- specimen 5 [adult]: Alb_sze ZIN 1_05 head dorsal.jpg; Alb_sze ZIN 1_05 head ventral.jpg; Alb_sze ZIN 1_05 specimen dorsal middle.jpg; Alb_sze ZIN 1_05 specimen dorsal.jpg; Alb_sze ZIN 1_05 specimen ventral.jpg

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(2) Theromyzon maculosum (Rathke, 1862)
= Hemiclepsis tessellata Plotnikov (1907): 139 [partim; identification error]
Lot ZIN 14/44093, labelled “Lake Alyk-Nor, southern slope of Burkhan-Burda, 12,700' a.l., 29.v.1900 [Julian calendar date], Tibetan Expedition leg.” [China: Lake ‘Alyk-Nor’, 35.5660°N, 97.1218°E, 4,100 m alt., southern slope of Burchan-Budda Mountain Range, Dulan County, Haixi Mongol and Tibetan Autonomous Prefecture, Qinghai, 11 June 1900, collected by P.K. Kozlov's expedition to Mongolia and Tibet] (2 adults, one sub-adult, and 61 juveniles; all illustrated here)
Image files (13 photos):
- sample label: The_mac ZIN 14-44093 label.JPG
- specimen 1 [adult]: The_mac ZIN 14-44093 specimen 1 D 1.jpg; The_mac ZIN 14-44093 specimen 1 D 2.jpg; The_mac ZIN 14-44093 specimen 1 head V.jpg; The_mac ZIN 14-44093 specimen 1 V.jpg
- specimen 2 [sub-adult]: The_mac ZIN 14-44093 specimen 2 D.jpg; The_mac ZIN 14-44093 specimen 2 head V.jpg; The_mac ZIN 14-44093 specimen 2 V.jpg
- specimen 3 [adult]: The_mac ZIN 14-44093 specimen 3 D.jpg; The_mac ZIN 14-44093 specimen 3 head V.jpg; The_mac ZIN 14-44093 specimen 3 V.jpg
- juvenile specimens: The_mac ZIN 14-44093 juveniles part 1.jpg; The_mac ZIN 14-44093 juveniles part 2.jpg

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(3) Theromyzon mollissimum (Grube, 1871)
= Hemiclepsis tessellata Plotnikov (1907): 139 [partim; identification error]
Lot ZIN 13/44092, labelled “Eastern Qaidam, Khara-Usu River, approx. 8,600' a.l., [2] August 1901 [Julian calendar date], Tibetan Expedition leg.” [China: Hala Wusu River, 36.2792°N, 97.4192°E, approx. 2,800 m alt., eastern part of the Qaidam Basin, Qinghai, 15 August 1901, collected by P.K. Kozlov's expedition to Mongolia and Tibet] (11 adults, one sub-adult, and 261 juveniles; all illustrated here)
Image files (35 photos):
- sample label: The_mol ZIN 13-44092 label.JPG
- specimen 1 [adult]: The_mol ZIN 13-44092 specimen 1 D camera.jpg; The_mol ZIN 13-44092 specimen 1 D.jpg; The_mol ZIN 13-44092 specimen 1 head D.jpg; The_mol ZIN 13-44092 specimen 1 head V.jpg; The_mol ZIN 13-44092 specimen 1 V camera.jpg; The_mol ZIN 13-44092 specimen 1 V.jpg
- specimen 2 [adult]: The_mol ZIN 13-44092 specimen 2 D.jpg; The_mol ZIN 13-44092 specimen 2 head D.jpg; The_mol ZIN 13-44092 specimen 2 head V.jpg; The_mol ZIN 13-44092 specimen 2 V.jpg
- specimen 3 [sub-adult]: The_mol ZIN 13-44092 specimen 3 D.jpg; The_mol ZIN 13-44092 specimen 3 head V.jpg; The_mol ZIN 13-44092 specimen 3 V.jpg
- specimen 4 [adult]: The_mol ZIN 13-44092 specimen 4 D camera.jpg; The_mol ZIN 13-44092 specimen 4 V camera.jpg
- specimen 5 [adult]: The_mol ZIN 13-44092 specimen 5 D camera.jpg; The_mol ZIN 13-44092 specimen 5 V camera.jpg
- specimen 6 [adult]: The_mol ZIN 13-44092 specimen 6 D camera.jpg; The_mol ZIN 13-44092 specimen 6 V camera.jpg
- specimen 7 [adult]: The_mol ZIN 13-44092 specimen 7 D camera.jpg; The_mol ZIN 13-44092 specimen 7 V camera.jpg
- specimen 8 [adult]: The_mol ZIN 13-44092 specimen 8 D camera.jpg; The_mol ZIN 13-44092 specimen 8 V camera.jpg
- specimen 9 [adult]: The_mol ZIN 13-44092 specimen 9 D camera.jpg; The_mol ZIN 13-44092 specimen 9 V camera.jpg
- specimen 10 [adult]: The_mol ZIN 13-44092 specimen 10 D camera.jpg; The_mol ZIN 13-44092 specimen 10 V camera.jpg
- specimen 11 [adult]: The_mol ZIN 13-44092 specimen 11 D camera.jpg; The_mol ZIN 13-44092 specimen 11 V camera.jpg
- specimen 12 [adult]: The_mol ZIN 13-44092 specimen 12 D camera.jpg; The_mol ZIN 13-44092 specimen 12 V camera.jpg
- juvenile specimens: The_mol ZIN 13-44092 juveniles part 1.jpg; The_mol ZIN 13-44092 juveniles part 2.jpg; The_mol ZIN 13-44092 juveniles part 3.jpg

REFERENCES
Andreev A, Yusupova T. Pyotr Kuz’mich Kozlov (1863–1935). In: Andreev AI, Baskhanov M, Yusupova T (eds) The Quest for Forbidden Lands: Nikolai Przhevalskii and his Followers on Inner Asian Tracks. Leiden: Brill, 2018; 212–254. https://doi.org/10.1163/9789004376267_006
Bolotov IN, Eliseeva TA, Gofarov MY, Tsiplenkina IG, Kondakov AV. Taxonomic diversity of leeches on the world's highest mountain ranges and plateaus. Zoological Journal of the Linnean Society 2005. https://doi.org/10.1093/zoolinnean/zlaf051
Kozlov PK. Through Mongolia to the boundaries of Tibet. In: Mongolia and Kam: Proceedings of the Expedition of the Imperial Russian Geographic Society carried out in 1899-1901 under the leadership of P. K. Kozlov. Vol. 1, Part 1. Saint Petersburg: Herold, 1905; 1–256. [in Russian]
Kozlov PK. Kam and way back. In: Grigoriev AV (ed) Mongolia and Kam: Proceedings of the Expedition of the Imperial Russian Geographic Society carried out in 1899-1901 under the leadership of P. K. Kozlov. Vol. 1, Part 2. Saint Petersburg: Herold, 1906; 1–732. [in Russian]
Plotnikov V. Glossosiphoniidae, Hirudinidae et Herpobdellidae du Musée Zoologique de l'Académie Impériale des Sciences. Annuaire du Musée zoologique de l'Académie des sciences de St. Pétersbourg 1907;10:133–158. https://www.biodiversitylibrary.org/item/121130#page/5 [in Russian]