Prosoma-abdomen stridulatory mechanism in Knoflachia kurilensis sp. nov. A posterior margin of male carapace, prosomal stridulatory ridges B the same, enlarged C posterior margin of female carapace (note absence of PSR) D male abdominal stridulatory pick row E the same, enlarged F female abdominal stridulatory pick row (note dome-like setal bases of SPR, the same as surrounding setal bases). Abbreviations: PSR – prosomal (carapace) stridulatory ridges; SPR – stridulatory pick row.