Fossil of Crenulosepta perlisensis （圖片來源：Fassihi S et al. (2024)，採用  CC BY 4.0  授權） Age Permian（Artinskian） 290.1-283.5 Ma Taxonomy Phylum: Retaria Subphylum: Foraminifera Order: Fusulinida Family: Schwagerinidae Genus: Crenulosepta Species: Crenulosepta perlisensis Morphological description The test of Crenulosepta perlisensis  is planispirally coiled, with mature individuals typically completing five to six whorls. From early growth to the adult stage, the shell maintains a