Morpho-species of the genus Leuciscus Cuvier, 1816 (Teleostei: Leuciscinae) from Iran revisited using molecular approaches

Abstract

Leuciscus is a genus of fish belonging to subfamily Leuciscinae. While, it is widely distributed throughout Eurasia, our perception of the phylogenetic relationships among its members is mainly based on morphological characters. In this study, two mitochondrial (CYTB and COX1) and one nuclear (RAG1) genomic markers were used in order to assess the taxonomic relationships between two Iranian Leuciscus morpho-species. Analysis of the combined dataset using Maximum Likelihood (ML) and Bayesian Inference (BI) resulted in well-resolved trees, where most clades were supported by high statistical values. The trees revealed two clades corresponding with the Caspian Asp, Leuciscus aspius, and the Mesopotamian Asp, L. vorax. The mean intraspecific and interspecific genetic distance between Leuciscus species was 0.5% and 10.6%, respectively. The genetic distance between L. aspius sequences of Iran and Europe was 1.1% and the genetic distance between L. vorax sequences from Iran and those of Turkey and Syria was 0.8%. This confirmed that the morpho-species Leuciscus from the Caspian basin belongs to L. aspius, while those from the Tigris basin belong to L. vorax. Due to very small genetic distances between some Leuciscus members, specific species delimitation analyses are required to clarify genus taxonomy throughout its distribution range.