Radiographs of the caudal skeleton in Astronotus species showing magnified details A A. mikoljii sp. nov. (MHNLS 24059, 205.5 mm SL) B A. crassipinnis INPA-ICT 33889 (204.3 mm SL) C A. ocellatus USNM 284442 (79.6 mm SL). Abbreviations: hypurapophysis (PP) of parahypural bone (PH), epurals (E1 – E2) and neural spine (NEU2, diastema (D), preural centrum (CP), epaxial caudal rays (ECR), hypaxial caudal rays (HCR), epaxial procurrent caudal rays (EPCR) hypaxial procurrent caudal rays (HPCR). Scale bars: 2 mm.