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PROTISTS 217





                        Box 9.5 Classifi cation of the radiolarians

               The classification of the radiolarians is currently in a state of flux. Six orders are recognized (De


               Wever et al. 2001).
               Order ARCHAEOSPICULARIA
               •  Mid Cambrian to Silurian

               Order ALBAILLELLARIA
               •  Late Ordovician to Late Silurian or ?Devonian
               Order LATENTIFISTULARIA
               •  Early Carboniferous (or earlier?) to Permian

               Order SPUMELLARIA
               •  Paleozoic (precise age uncertain) to Recent
               Order ENTACTINARIA
               •  (?Cambrian), Ordovician to Recent

               Order NASSELLARIA
               •  (?Late Paleozoic), Triassic to Recent



                            SPUMELLARIA









                              Lenosphaera                                      Alievium
                                                    Actinomma

                            NASSELLARIA













                                                                               Peripyramis


                                                      Calocyclas
                             Anthocyrtidium
             Figure 9.10  Some radiolarian morphotypes: Lenosphaera (×100), Actinomma (×240), Alievium (×180),
             Anthocyrtidium (×250), Calocyclas (×150) and Peripyramis (×150).
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