Rotifers of southwest Iran: a faunistic and biogeographical study

The fauna of freshwater rotifers from Khuzestan Province (Southwest Iran) was expected to be different from that of the rest of Iran because of its geographical position, past geological events, climatic conditions, and similarities to neighboring zoogeographical areas. To test this hypothesis, we first had to determine the rotifer fauna of Khuzestan and then compare it with the results of surveys from other parts of Iran as well as with those from neighboring regions. Samples were collected from 10 sites throughout the province from May 2009 to April 2010. During the study, 66 species were identified, mostly with distribution in tropical and subtropical areas, from which 21 species are new to Iranian fauna. Surprisingly, one of the species, Colurella sanoamuangae, is not only new to the Iranian fauna, but also to the Palearctic region. Furthermore, another species, Lecane inconspicua, is, for the first time, reported outside the Arabian Plate. Comparisons among the rotifer fauna of Khuzestan, the rest Iran, and the Palearctic, Afrotropical, and Oriental regions, using the Sorenson similarity index, revealed considerable similarities between Khuzestan's fauna and those of the Afrotropical and Oriental regions.