LAUSR

The presence of exotic earthworms has recently become a major concern and drawn significant attention to their potential effects on ecosystems and native invertebrate fauna. Although the occurrence of invasive annelids has been well recorded, their settlement in Iran is poorly documented. To investigate the biodiversity of aquatic Oligochaeta and to assess the presence of possible exotic species, DNA barcoding using the mitochondrial cytochrome c oxidase subunit 1 (COI) gene was conducted in two major protected rivers (Jajroud, Karaj) of the southern Alborz Mountains. As a result, new lineages of Tubifex, Haplotaxis and Lumbriculus were identified from Iran. Moreover, a semiaquatic lumbricid species, Eiseniella tetraedra, was unexpectedly found to be the most abundant species. The analyses showed the presence of six divergent lineages of E. tetraedra occurring in individual rivers. The presence of identical haplotypes shared between European, North American, Australian and Iranian localities, the sympatric accumulation of several distinct intraspecific lineages in the same rivers and the lack of a phylogeographic pattern reinforce the hypothesis of a possible inadvertent anthropogenic introduction. The relative abundance of lineages indicates a significant decline in the abundance of native oligochaetes, which may be linked to the preponderance of recently introduced European populations of E. tetraedra, probably mediated through human activities.