Triplophysa ferganaensis Sheraliev & Peng, 2021

Triplophysa ferganaensis Sheraliev & Peng, 2021 View in CoL

( Fig. 1 View Figure 1 )

Triplophysa ferganaensis Sheraliev & Peng, 2021 View in CoL , Journal of Fish Biology   GoogleMaps , 99, 809 (Type locality: Uzbekistan, Fergana Region   GoogleMaps , Fergana District   GoogleMaps , Shakhimardan   GoogleMaps stream in Yordon village, an exclave of Uzbekistan in Kyrgyzstan, Syr Darya basin, 39°57'50.5"N 71°45'38.8"E, altitude 1581 m)

Material examined. FSU082019650–654 View Materials , paratypes, 5 specimens, 54.6–99.8 mm SL; Uzbekistan: Fergana Region : Oqsuv River in Yordon village, an exclave of Uzbekistan in Kyrgyzstan, 39°57'50.5"N 71°45'38.8"E, 13.08.2019, collected by B.Sheraliev & E.Jalolov GoogleMaps ; BSFC 0218 , 35 specimens, 57.9–99.8 mm SL; Uzbekistan: Fergana Region : Shohimardonsoy River near Vodil town, close to the Uzbekistan – Kyrgyzstan border, 40°09'42.9"N 71°43'43.2"E, 06.04.2025, collected by B.Nazirov GoogleMaps ; BSFC 0219 , 36 specimens, 49.7–84.9 mm SL; Uzbekistan: Fergana Region : Oltiariqsoy River at the Chimyon Health resort, 40°15'13.8"N 71°35'20.5"E, 06.04.2025, collected by B.Nazirov GoogleMaps ; BSFC 0220 , 41 specimens, 51.2–98.5 mm SL; Uzbekistan: Fergana Region : under the bridge on Isfayramsoy River 200 m to “Islom” Jami mosque, 40°17'47.6"N 71°58'15.5"E, 06.04.2025, collected by B.Nazirov GoogleMaps ; BSFC 0221 , 36 specimens, 51.2–98.5 mm SL; Uzbekistan: Namangan Region : Podshootasoy River in Nanay village near “Kamalak” Camp, 41°27'19.5"N 71°41'15.8"E, 06.04.2025, collected by B.Nazirov. GoogleMaps

Diagnosis. The species is distinguished from Triplophysa species known from the Fergana Valley by the following combination of characters: having a relatively deeper body at dorsal-fin origin (14–19% of SL vs. 12–15% in T. daryoae ); a wider caudal peduncle (CPD 1.9–2.9 times in its length vs. 3.2–3.5 in T. elegans ; 7–10% of SL vs. 5–7% in T. strauchii ); an emarginated caudal fin (vs. truncate in T. daryoae ); absence of posterior chamber of air bladder (vs. presence in T. dorsalis and T. strauchii ); a shorter postorbital head length (33–43% of HL vs. 44–48% in T. elegans ); 10–11 inner gill rakers on the first gill arch (vs. 13–16 in T. dorsalis , 13–14 in T. elegans , 12–16 in T. strauchii ); pelvic fin with 7–8 branched rays (vs. 6 in T. daryoae ); caudal fin with 16 branched rays (vs. 14 in T. daryoae ); 39–40 vertebrae (vs. 42–43 in T. elegans , 41–42 in T. strauchii ); dorsal-fin origin opposite to pelvic-fin insertion (vs. anterior to vertical of pelvic-fin origin in T. dorsalis , T. elegans , and T. strauchii ) ( Fig. 1 View Figure 1 ). Morphometric characteristics of T. ferganaensis from the Shohimardonsoy, Oltiariqsoy, Isfayramsoy, and Podshootasoy rivers are presented in Table 1.

A principal component analysis (PCA) was performed using morphometric data from T. ferganaensis specimens collected from the Shohimardonsoy, Oltiariqsoy, Isfayramsoy, and Podshootasoy rivers. The first two principal components, PC1 and PC2, accounted for 20.16% and 10.00% of the total variance, respectively. PC1 was mainly influenced by standard length, fin lengths, and caudal peduncle depth and width, whereas PC2 was predominantly shaped by head and body depthrelated variables. The PCA scatter plot showed broad overlap among individuals from all four populations in multivariate space, with no clear separation between groups. This considerable overlap supports the conclusion that all examined populations represent a single, morphologically cohesive species ( Fig. 2 View Figure 2 ).

Distribution. Triplophysa ferganaensis was originally described from the upper reaches of the Shohimardonsoy River and was initially thought to be endemic to high-mountain streams (above 1500 m a.s.l.) within this drainage ( Sheraliev & Peng 2021). Subsequent studies reported its occurrence in the middle reaches of the Shohimardonsoy River, at approximately 900 m a.s.l., as well as from the Oltiariqsoy River, a left-hand branch of the Shohimardonsoy ( Sheraliev et al. 2024a). Additionally, its presence in the middle reaches of the Isfayramsoy River—located to the east of the Shohimardonsoy— was confirmed using DNA barcoding ( Sheraliev et al. 2024a). However, T. ferganaensis was not recorded during field surveys conducted in the lower reaches of both the Shohimardonsoy and Isfayramsoy rivers, which flow through the lowland areas of the Fergana Valley ( Sheraliev et al. 2024b; Rakhmonov et al. 2024). More recently, the species was reported from the upper reaches of the Istara River in Tajikistan, at an elevation of approximately 1470 m a.s.l., located about 250 km southwest of the type locality ( Fig. 3 View Figure 3 ), indicating a broader distribution than previously assumed ( Artaev et al. 2025).

In the present study, we recorded T. ferganaensis from the Podshootasoy River in the northern part of the Fergana Valley ( Fig. 3 View Figure 3 ), indicating that its distribution range is broader than previously assumed. Given that T. ferganaensis has so far been recorded only from mountainous streams and is absent from the lowland areas of the Fergana Valley, we suggest that the species may also be present in other high-altitude rivers in the eastern and northeastern parts of the valley, spanning across both Uzbekistan and Kyrgyzstan. Potential habitats may include major rivers and tributaries such as the Naryn, Maylisuu, Kara Ungur, Kögart, Yassy, Tar, Kurshab, Ak-Buura, Aravansoy, Karasu, and Karakulja, and their associated streams. However, further ichthyological surveys are necessary to confirm the species’ presence in any of these water bodies.

Ecology and biology. Triplophysa ferganaensis is primarily adapted to cold, fast-flowing mountain rivers and streams with gravelly and rocky substrates ( Fig. 4 View Figure 4 ). Although no migration barriers (e.g., dams) are present along the surveyed sites within Uzbekistan, it should be noted that several dams exist in the upper reaches of the Isfayramsoy River in Kyrgyzstan, which may potentially limit downstream movement. Nevertheless, T. ferganaensis has not been recorded in the lower reaches of either the Shohimardonsoy or Isfayramsoy rivers. In the Shohimardonsoy, it commonly cohabits with Schizothorax eurystomus Kessler, 1872 ; in the Isfayramsoy, it shares its habitat with both S. eurystomus and Glyptosternon oschanini (Herzenstein, 1889) ; and in the Podshootasoy, it is primarily found alongside S. eurystomus and I. kuschakewitschi (Herzenstein, 1890) . All of these are typical high-altitude fish species, and they are occasionally observed forming mixed shoals.

The diet of T. ferganaensis consists primarily of aquatic insect larvae and imagos, with benthic algae making up a smaller portion. Stomach and intestinal content analysis revealed remains of insects from the orders Diptera (mainly Chironomidae ) and Trichoptera. Spawning occurs from May to August. The eggs are small, with an average diameter of 0.76 mm (0.43–0.98 mm), and fecundity reached up to 8,700 eggs, with observed values ranging from 2,438 to 12,909 (n = 12).

Remark. The present record of T. ferganaensis from the Podshootasoy River represents the northernmost known occurrence of the species. This finding provides important insights into the species’ distributional boundaries and contributes to a more comprehensive understanding of the ichthyofaunal composition of the region. The documented occurrence of T. ferganaensis in high-altitude streams— specifically in the Shohimardonsoy River (1581 m a.s.l.; Sheraliev & Peng 2021), the Istara River (1470 m a.s.l.; Artaev et al. 2025), and the Podshootasoy River (1230 m a.s.l.)—together with the absence of verified records from lowland habitats of the Fergana Valley, suggests that this species may serve as a valuable model organism for investigating ecological and physiological adaptations to high-altitude environments in freshwater fishes.

To further clarify the distributional range of T. ferganaensis , additional ichthyological surveys are needed in mountain rivers, streams, and creeks surrounding the Fergana Valley. Such investigations are also vital for generating reliable data to inform future assessments of the species’ conservation status.

Acknowledgements

We are grateful to Mahmudbek Madaliev and Zukhriddin Kholmirzaev (Fergana State University) for their support during fieldwork. We also thank Murodjon Rakhmonov (Fergana State University) for granting permission to use his photographs in Figures 1d View Figure 1 and 4d View Figure 4 . We also thank the anonymous reviewers for their helpful comments and suggestions, which improved the quality of the manuscript.

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