Micropalaeosoma balticus is an extinct, fossil turbellarian flatworm known from Baltic amber from an exclave between what two countries? 
Micropalaeosoma: Micropalaeosoma balticus (formerly "Palaeosoma balticus" ) is an extinct, fossil turbellarian flatworm known from Baltic amber of Kaliningrad, Russia, that lived approximately 40 million years ago. Kaliningrad: Kaliningrad (Russian: Калининград ; ] ) (former German name: Königsberg; Russian: Кёнигсберг , "Kyonigsberg" ; Old Prussian: "Twangste, Kunnegsgarbs, Knigsberg "; Polish: "Królewiec" ; Lithuanian: "Karaliaučius" ) is the administrative center of Kaliningrad Oblast, a Russian exclave between Poland and Lithuania on the Baltic Sea.
Poland and Lithuania