A Morpho-molecular Perspective on the Diversity and Evolution of Spumellaria (Radiolaria)

摘要: Abstract Spumellaria (Radiolaria, Rhizaria) are holoplanktonic amoeboid protists, ubiquitous and abundant in the global ocean. Their silicified skeleton preserves very well sediments, displaying an excellent fossil record extremely valuable for paleo-environmental reconstruction studies, from where most of their extant diversity ecology have been inferred. This study represents a comprehensive classification based on combination ribosomal taxonomic marker genes (rDNA) morphological characteristics. In contrast to established knowledge, we demonstrate that symmetry takes more importance than internal structures at high ranks. Such reconsideration allows gathering different morphologies with concentric structure spherical or radial believed belong other Radiolaria orders record, as some Entactinaria families. Our calibrated molecular clock dates origin middle Cambrian (ca. 515 Ma), among first radiolarian representatives record. direct connection between living specimens extinct Cambrian, bringing both standpoint future environmental surveys better understanding analysis.