Molecular systematics and morphological variation in the Mesopotamian spiny eel <i>Mastacembelus mastacembelus</i> (Teleostei: Mastacembelidae)

The Mesopotamian spiny eel, Mastacembelus mastacembelus, an endemic freshwater fish restricted to the Euphrates and Tigris river drainages of Mesopotamian, its related taxa in Afrotropica South Asia present suitable elements for studies evolutionary history mastacembelids across these heterogeneous areas. To understand clarify geographic variation eel from Persian Gulf basin, we investigated molecular morphological characteristics individuals collected whole distribution range (Karkheh, Karoon Zab), Zohreh Persis (Mond Helleh) main Iran. analysis revealed a separation studied populations; however, genetic distances were relatively small tree did not distinct branching pattern based on COI mitochondrial marker. Six haplotypes identified: Helleh, Mond, Karkheh, Karoon, Zab tributaries each showed separate haplotype. marker indicates that has greater affinity with African species than Southeast Asian species. Estimation divergence times apparently diverged about 1 million years ago (Mya) (95% highest posterior density [HPD]: 390,000 2.1 Mya) different basin.