A sole couple of mating specimens of the extinct genus Globularia, an ampullinid gastropod is described from the Paleocene Chehelkaman Formation in the eastern part of the Kopet-Dagh Basin, northeast Iran. Difference in size between the mating specimens is an indication of sexual dimorphism, with the female being larger than the male in overall size. The data suggests that males of this taxon preferred to mate with large females. The identifiation of the larger individual as the female is confimed by the presence of scars corresponding to the egg capsules that she carried on the dorsal part of the shell. This study is the second report of a mating behavior observed in the ampullinid fossil record. It is indicative of a rapid burial during coupling.

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