Late‐Quaternary Cladocera of Lake Zeribar Western Iran

Abstract

Between about 22,500 and 12,000 years ago cosmopolitan and northern Chydoridae were dominant in Lake Zeribar. Species with southern affinities replaced the northern species between 12,000 and 5,000 years ago. During the last 5,000 years the chydorid fauna has been composed of southern and cosmopolitan species, and the planktonic cladoceran, Bosmina longirostris, has been more abundant than it was earlier in the lake's history. The fauna prior to 12,000 years ago was similar in several ways to the fauna in Allerod lake sediments in Germany and England, thus implying a cool temperate climate in the vicinity of Lake Zeribar during the latest Pleistocene. The replacement of northern species by southern species between 12,000 and 5,000 years ago suggests gradual warming, but temperatures probably never have been warmer than they are now. Th chydorid assemblage has been relatively stable during the last 5,000 years. The abundance of planktonic Cladocera during this interval suggests that the lake probably has been deeper than at any time during its earlier history, and that rainfall was probably greater than before.