Sakhalin amber was originally described as Late Paleocene in age, but correct age is Middle Eocene (43-47 Ma) according to Radchenko & Perkovsky (2016).
†Protopone primigenaDlussky, 1988aPDF: 53, fig. 2 (w.) RUSSIA (Eocene). Primary type information: Russia, Sakhalin Island, Starodubskoe; middle Eocene (43-47 Ma); PIN 3387/31; Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russia (PIN) AntCatAntWikiHOL