A putative twisted-wing parasitoid planidium (Insecta: Strepsiptera) in Taimyr Upper Cretaceous amber

A planidium is newly recorded from Upper Cretaceous (Santonian) amber of the Taimyr Peninsula, Krasnoyarsk Territory, Siberia. This peculiar fossil is tentatively attributed to the order Strepsiptera, representing the first record of this lineage from these deposits. Planidia of a similar conicocephalate form are known from the slightly younger amber of western Canada (Campanian) as well as in the earlier (Cenomanian) amber of Myanmar, and comparisons are made with those fossils, as well as with living Strepsiptera and the beetle family Ripiphoridae (Tenebrionoidea). Given recent debate concerning the strepsipteran attribution of these planidia, we provide some discussion about the available and expected character evidence, and tend to believe assignment to Ripiphoridae is untenable. While placement with Strepsiptera remains difficult to state conclusively, the current limited evidence still tends to prefer the strepsipteran hypothesis.