Fossil of Crenulosepta perlisensis （Image source：Fassihi S et al. (2024)， CC BY 4.0 ） 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 maintai