MORPHOLOGICAL DIFFERENTIATION OF ISKANDARIA KUSCHAKEWITSCHI (HERZENSTEIN, 1890) POPULATIONS DISTRIBUTED IN THE CHORTOQSOY AND OLTIARIQSOY RIVERS

Abstract

This study presents a comparative analysis of the morphological differentiation of Iskandaria kuschakewitschi populations distributed in the Chortoqsoy and Oltiariqsoy rivers. A total of 15 specimens from the Chortoqsoy population and 19 specimens from the Oltiariqsoy population were examined. Morphometric measurements were obtained following the methodology proposed by Kottelat and Freyhof (2007), and statistical analyses were performed using Student’s t-test. The results revealed significant differences in 14 out of 33 morphometric characters between the two populations. The most pronounced differences were observed in head length, predorsal and postdorsal lengths, fin lengths, and caudal peduncle parameters. Coefficients of variation indicated a higher level of morphological variability in the Oltiariqsoy population. The detected differences may be associated with variation in ecological conditions, hydrological regime, and microhabitat characteristics of the studied river systems. The findings provide an important scientific basis for further ecological, morphological, and taxonomic studies of local populations of Iskandaria kuschakewitschi in the Fergana Valley.