taxonID	type	description	language	source
03E287F9F47AFFD6DDFCFA37FBB2F9AF.taxon	type_taxon	TYPE SPECIES. — Hirudo complanata Linnaeus, 1758, designated by R. Blanchard (1894).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47AFFD7DDACF9D6FE98FD91.taxon	description	(Figs 1; 2 A)	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47AFFD7DDACF9D6FE98FD91.taxon	materials_examined	MATERIAL EXAMINED. — Holotype. Uzbekistan • Ferghana Valley, Andijan region, Balikchi district, Kaynarbulak spring; 8. VI. 2020; Kh. Solijonov leg; ASUZM 155. ADDITIONAL DATA. — See Appendix 1.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47AFFD7DDACF9D6FE98FD91.taxon	diagnosis	DIAGNOSIS. — Small-sized leech. Body length of juvenile leeches 7 - 16 mm, width 2 - 3 mm; length of adults 17 - 26 mm, width 3 - 7 mm. Body ovate. Dorsal side orange-amber, with very small dark-green spots, body surface smooth, with no papillae and tubercles. Ventral side yellow, with no spots. Three pairs of eyes arranged in 2 parallel rows, round-shaped; 2 posterior pairs larger than anterior one; anteriormost pair of eyes hardly discernible. 69 - 70 annuli of the same length. Mid-body segment 3 - annulate. Gonopores separated by two annuli. Six pairs of crop caeca, posterior crop caeca not branched.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47AFFD7DDACF9D6FE98FD91.taxon	discussion	REMARK As for now, it is found that this species is endemic to the Ferghana Valley.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DEA3FC91FD20F86A.taxon	description	(Figs 1; 2 B)	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DEA3FC91FD20F86A.taxon	materials_examined	MATERIAL EXAMINED. — Uzbekistan • 10 samples; Ferghana Valley, Andijan region; 22. III. 2020; Kh. Solijonov leg.; Department of Zoology and Animal Ecology, V. N. Karazin Kharkiv National University. PREVIOUS RECORDS. — Central Asia • 1 sample; Akmola region, Kazakhstan; 3. VIII. 1899; Ignatov leg. (Plotnikov 1907) • 20 samples; Amu Darya River, Turkestan (currently Uzbekistan); 11. VI. 1911; Moltschanov leg. (Moltschanov 1913) • 1 sample; Issyk-Kul, Kyrgyzstan; 13. VII. 2005; (Jueg et al. 2013). ADDITIONAL DATA. — See Appendix 1.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DEA3FC91FD20F86A.taxon	diagnosis	DIAGNOSIS. — Body length of juvenile leeches 2 - 4 mm, width 1 - 2 mm, adults 5 - 12 mm in length, and 4 - 8 mm in width. When the body is at rest, the leech has a leaf-like shape. Body margins smooth. Many tiny papillae scattered on dorsal surface. Three pairs of eyes: first pair smaller and closer together; posterior two pairs larger, with a greater distance between them. Dorsal and ventral sides yellowish-white. No dark pigmentation. Digestive organs can be seen through body coverings. Six pairs of crop caeca: 1 st pair smaller; 2 nd- 5 th pairs longer, with the 5 th pair branching into four pouches.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DEA3FC91FD20F86A.taxon	discussion	REMARK This species was recorded for the first time in the Ferghana Valley of Uzbekistan based on both morphological characters and molecular data. Collected samples are small.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DF4CFDF2FEA0FD72.taxon	type_taxon	TYPE SPECIES. — Hirudo heteroclita Linnaeus, 1761, designated by Lukin (1976).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DDC9FF73FA00FB2F.taxon	description	(Figs 1; 2 C)	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DDC9FF73FA00FB2F.taxon	materials_examined	MATERIAL EXAMINED. — Uzbekistan • 6 samples; Ferghana Valley, Andijan region; 22. III. 2020; Kh. Solijonov leg.; Department of Zoology and Animal Ecology, V. N. Karazin Kharkiv National University. ADDITIONAL DATA. — See Appendix 1.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DDC9FF73FA00FB2F.taxon	diagnosis	DIAGNOSIS. — Small-sized leech. Body length of young leeches 2 - 4 mm, width 1 - 2 mm, adults 5 - 12 mm in length and their width 3 - 8 mm. Body elongated oval-shaped at rest. Body margins denticulate. Dorsal body surface with well-developed tubercles. Three pairs of eyes: 1 st pair smaller and closer together; 2 nd and 3 rd pairs larger, with a greater distance between them. Body colour mostly white, almost transparent. Therefore, after feeding, the digestive organs can be seen with the naked eye through the body coverings. Median row of black dots on dorsum present. Live and freshly fixed leeches with segmentally arranged transverse lateral black bands, numerous paramedian black lines, and tiny dots on dorsum. Six pairs of crop caeca: 1 st pair smallest; 2 nd – 5 th pairs longer; posterior crop caeca branched into five pouches (Solijonov et al. 2023).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DDC9FF73FA00FB2F.taxon	discussion	REMARK This species, a leech native to the Oriental region, was first recorded in the Ferghana Valley of Uzbekistan and Central Asia based on both morphological characters and molecular data.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD7DDFCFB50FC50FA0F.taxon	type_taxon	TYPE SPECIES. — Hirudo stagnalis Linnaeus, 1758, designated by R. Blanchard (1896).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD9DDEEFA76FA01FB2F.taxon	description	(Figs 1; 2 D)	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD9DDEEFA76FA01FB2F.taxon	materials_examined	MATERIAL EXAMINED. — Uzbekistan • 10 samples; Ferghana Valley, Andijan region; 22. III. 2020; Kh. Solijonov leg.; Department of Zoology and Animal Ecology, V. N. Karazin Kharkiv National University PREVIOUS RECORDS. — Central Asia • 1 sample; Samarkand region, Uzbekistan; 2. XI. 1898; Retter leg. • 2 samples; Kurgaldzhin Lake in the Akmola region, Kazakhstan; 14. VI. 1899; Ignatov leg. (Plotnikov 1907) • 59 samples; Ashkhabad, Turkmenistan; 9. II. 1911; (Shchegolev & Shchegoleva 1951) • 7 samples; Issyk-Kul, Kyrgyzstan; 13. VII. 2005; (Jueg et al. 2013). ADDITIONAL DATA. — See Appendix 1.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD9DDEEFA76FA01FB2F.taxon	diagnosis	DIAGNOSIS. — Body length at full elongation 8 - 20 mm, body width 6 - 12 mm. Body oblong-oval at rest, middle of body wider than anterior end, body slightly tapered posteriorly. During movement, the body can be stretched up to three times more than in a calm state. Body margins denticulate, better expressed in fixed specimens. Dorsal body surface smooth. Body appearing yellowish-grey when stretched and green when shortened due to the presence of dark green spots (dots) on the back surface of the body. They are smaller and more numerous on the posterior portion of the body and larger and less numerous on the anterior portion. Brown chitinous scutum located on trachelosome. One pair of clearly separated eyes.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD9DDEEFA76FA01FB2F.taxon	discussion	REMARK This species was recorded for the first time in the Ferghana Valley of Uzbekistan. Collected samples are small.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F47BFFD9DDEEFA76FA01FB2F.taxon	description	MOLECULAR GENETIC ANALYSIS Helobdella stagnalis (Linnaeus, 1758) Helobdella stagnalis formed a distinct clade on the phylogenetic tree of the genus Helobdella (log-likelihood: – 13015.5363 [s. e. 600.4929]). The Ferghana scute-bearing leech clustered with H. stagnalis, occupying a sister position to the Daghestan leech (Fig. 3; Supplementary material 1. Another sequence from Uzbekistan did not group within this clade. The Helobdella stagnalis clade consists of two major monophyletic groups that can be designated as the Northern / Eastern Palearctic and Northern / Southern Palearctic clades to characterise their geographical distribution. The Ferghana leech was assigned to the former monophyletic group. The uncorrected genetic distance between the COI sequence of H. stagnalis from the Ferghana Valley and the other sequences of the clade of H. stagnalis is 0.0181 ± 0.0031. Neutrality tests were done to analyse if selection has played a role in the molecular evolution of the COI gene in H. stagnalis. The codon-based Z-test revealed purifying selection in the COI locus. Tajima’s D for the entire clade of Helobdella stagnalis does not reject the hypothesis of neutrality (Table 2).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F475FFDADD62F976FD69FD11.taxon	discussion	The COI sequence of A. hyalina from the Ferghana Valley was found to be sister to the sequence of the leech from the Tyumen Region in Russia (GenBank: ON 631769) identified as A. heteroclita. This clade is sister, in turn, to the clade of North American leeches (Fig. 5; Supplementary material 2). The uncorrected genetic distance between the COI sequence of A. hyalina and its sister sample is 0.0016 ± 0.0016.	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F475FFD9DD64FB70FB8AF92D.taxon	discussion	The genus Glossiphonia formed a separate clade sister to Alboglossiphonia on the phylogenetic tree (log-likelihood of the tree: - 5276.9902 [s. e. 268.2413]). Two closely related sequences assigned to G. ferghanensis formed a separate clade within the superclade of G. concolor (Fig. 4; Supplementary material 2). The uncorrected genetic distance between the two newly generated sequences of G. ferghanensis and the rest of the sequences of the clade of G. concolor is 0.0344 ± 0.0056 and the distance between the two conspecific sequences is 0.0015 ± 0.0016. Although the codon-based Z-test suggested purifying selection in the COI locus, Tajima’s D for the entire clade of G. concolor does not reject the hypothesis of neutrality (Table 2).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
03E287F9F476FFDADECBFD11FD11FC4E.taxon	discussion	The COI sequence of A. weberi was found to be within the Myanmarese and Indian clade of A. pahariensis (Fig. 5; Supplementary material 2). The uncorrected genetic distance between the COI sequence of A. weberi from the Ferghana Valley and other members of the clade is 0.0207 ± 0.0056. Although the codon-based Z-test suggested purifying selection in the COI locus, Tajima’s D for the entire clade of A. weberi does not reject the hypothesis of neutrality (Table 2).	en	Khayrulla Solijonov, Serge Utevsky, Zuvaid Izzatullaev, Utevsky, Andriy (2026): At the boundary of two biogeographical realms: Palearctic and Oriental leeches (Hirudinea, Glossiphoniidae) of the Ferghana Valley, Uzbekistan. Zoosystema 48 (2): 41-54, DOI: 10.5252/zoosystema2025v48a2
