Comparative Skeletal Morphology and Adaptive Evolution of Three Schizothorax (Actinopterygii: Cypriniformes) Species in Xinjiang Revealed by Micro-CT

The genusSchizothoraxcomprises an important group of freshwater fishes in Xinjiang (China); however, detailed information on their skeletal anatomy remains limited. In this study, we combined micro-computed tomography (micro-CT) and traditional skeletal preparations to examine and compare the osteological characteristics of three representativeSchizothoraxspecies:Schizothorax biddulphi,Schizothorax eurystomus, andSchizothorax curvifrons. Distinct variations were observed in several skeletal structures, including the cranium, pharyngeal teeth, fin-supporting elements, and vertebrae. Among the three species,S. biddulphiandS. eurystomusshowed generally similar skeletal architectures, whereasS. curvifronsexhibited more pronounced osteological differences. These findings provide new comparative osteological data forSchizothoraxspecies and offer a morphological reference for future studies on the taxonomy, systematics, and conservation of these freshwater fishes.