Morphological characteristics and intraspecific structure of Triplophysa orientalis (Balitoridae: Nemacheilinae)

Abstract

The morphology and intraspecific structure of Triplophysa orientalis inhabiting the inland basins of Tsaidam (northeastern edge of the Tibetan Plateau) and the basin of the upper reach of the Huang He River in China were studied. Significant morphological differences between the populations from the inland basins and the Huang He River were revealed; the latter were distinguished as a separate subspecies T. o. hwanghoensis subsp. n. Intermediate character of some traits of the new subspecies between the nominative subspecies and T. hutjertjuensis was found; as a result, the status of the latter was reduced to the subspecies level. The synonymy of T. o. elongata with the nominative subspecies was confirmed. The differences between T. orientalis and T. obscura—morphologically poorly distinguishable species, sympatric in the basin of the upper reach of the Huang He River—were defined more exactly.