“…Sexual conflict, specifically sexual coercion, may drive the striking morphological modification and dimorphism [ 21 , 34 , 48 , 49 ]. For example, it is believed that copulatory struggles have driven the evolution of male grasping structures to overcome female resistance in water striders and relatives [ 27 , 33 , 34 , 50 , 51 ]. The new fossils exhibit conspicuous sexual dimorphism in the protibia: (1) the protibia is slightly curved in males ( figure 2 b,d ; electronic supplementary material, figure S4 b,c ), whereas in females, the protibia is straight ( figure 2 e ; electronic supplementary material, figure S2 a ); (2) the protibia of males is armed with 15–17 discontinuous clusters of pegs along the innermost edge, consisting of 2–12 in each cluster ( figure 2 b–d ; electronic supplementary material, figures S2 c,d and S4 b,c ), forming a comb-like structure that is absent in females ( figure 2 e ; electronic supplementary material, figure S2 a ).…”