A morpho-molecular perspective on the diversity and evolution of Spumellaria (Radiolaria)

Miguel M. Sandin, Tristan Biard, Sarah Romac, Luis O'Dogherty, Noritoshi Suzuki, Fabrice Not

Research output: Contribution to journalArticlepeer-review

Abstract

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

Original languageEnglish
Article number125806
JournalProtist
Volume172
Issue number3
DOIs
Publication statusPublished - 2021 Jul

Keywords

  • Barcoding
  • Molecular clock
  • Molecular diversity
  • Molecular evolution
  • rDNA
  • Spumellaria

ASJC Scopus subject areas

  • Microbiology

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