The oldest oligochaete cocoons (former cladocerans) from the upper Permian (Lopingian) freshwater Karaungir Lagerstätte of eastern Kazakhstan

Abstract Numerous oligochaete cocoons, previously interpreted as cladoceran crustaceans, are described from the upper Permian (Lopingian) freshwater Karaungir Lagerstätte in eastern Kazakhstan. The cocoons appear as small, wrinkled, ovoid capsules, prolonged into a neck at one pole and a long slender stalk at the other; both extensions are covered with minute ridges forming a striated pattern. By their size range and distinct (although limited) morphological features, the cocoons are identical to those of the extant freshwater genus Rhynchelmis Hoffmeister, 1843 (Oligochaeta: Lumbriculidae) and thus represent the oldest undoubted record of the Clitellata. We interpret Archedaphnia Smirnov, 1970 (= Propleuroxus Smirnov, 1970, n. syn.) as a genus for fossil microdrile oligochaete cocoons similar to those of Rhynchelmis , and synonymize all five species described in Archedaphnia and Propleuroxus under Archedaphnia kazakhstanica Smirnov, 1970 sensu lato.