Historical insights on nearly 130 years of research on Paleozoic radiolarians

This paper summarizes and highlights the history of descriptive genus-level taxonomy on Paleozoic radiolarians grouped in five major phases: 1) initial discoveries in the 1890s; 2) ignored during the first half of the 1900s; 3) renewed interest during the 1950s to 1970s; 4) the “fast” years of the late 1970s to 1990s; and 5) the early 21st century quest for the oldest and significant progress in the late Permian.  In the 1890s, radiolarians were identified with certainty by Hinde in Ordovician radiolarian cherts. Following Hinde’s great discovery, and after a 50-year dormant period, Deflandre revived the study of Paleozoic radiolarians through his groundbreaking study of Albaillella from Carboniferous phosphatic nodules, combined with his genius for understanding evolutionary implications. Additional important work was conducted in this third phase by Foreman, particularly with respect to the description of the radiolarian internal structures based on material extracted from Devonian carbonate nodules. The late 1970s saw an expansion in studies that made extensive use of the SEM for the description of Paleozoic radiolarians, many of which had been extracted from chert using HF methods. The potential of radiolarians to unveil the structure and geodynamic evolution of Paleozoic orogenic belts stimulated taxonomic interest during the 1980s and 1990s, a prerequisite for the elaboration of radiolarian biostratigraphic schemes, which was successfully achieved for the upper Paleozoic. The fifth phase follows the discovery of well-preserved Middle Cambrian radiolarians from Australia at the end of the 20th century and subsequent description by Won of beautifully preserved Cambrian and Ordovician fauna from western Newfoundland. Research on early Paleozoic radiolarians was the main driver for the increase of the number of new genera for the last two decades.