Micro-CT analysis of Katian radiolarians from the Malongulli Formation, New South Wales, Australia, and implications for skeletogenesis

Abstract A diverse and well-preserved radiolarian assemblage from the Malongulli Formation, New South Wales, Australia, contains 13 species representing 10 genera six families. One new genus, Wiradjuri , is introduced to accommodate pre-Devonian single-shelled entactiniid taxa, one species, Secuicollacta malongulliensis recorded together with some previously described forms. The microstructures of “rotasphaerid structure/primary unit” “ectopic spicule” are investigated validate their roles as fundamental units in Secuicollactidae, comprehensive documentation enigmatic Pseudorotasphaera internal skeleton. results this investigation suggest that, among all that survived Late Ordovician Mass Extinction event (LOME) transitioned into Silurian, Haplotaeniatum Palaeoephippium maintained stable body plans during transition were more successfully established. selective advantages these lineages had LOME most likely spontaneous outcomes mode structural development involving sequential skeletogenesis a tendency evolve toward simpler plans. UUID: http://zoobank.org/264c026f-35af-4025-a4f7-de8f9a91f8b9