AI Article Synopsis
- Life on Earth was primarily microbial for most of its history, leaving the Precambrian era largely mysterious due to the lack of fossil evidence, although some microfossils, particularly shelled amoebae known as vase-shaped microfossils (VSMs), provide valuable insights.
- A detailed study using advanced genomic techniques analyzed 250 genes from 19 Arcellinid testate amoeba species, resulting in a clearer understanding of their evolutionary relationships and necessitating a revision of their classification.
- The research suggests that significant diversification among testate amoebae occurred before the Sturtian glaciation around 720 million years ago, aligning with theories of early eukaryotic evolution linking VSMs to the
Article Abstract
Life was microbial for the majority of Earth's history, but as very few microbial lineages leave a fossil record, the Precambrian evolution of life remains shrouded in mystery. Shelled (testate) amoebae stand out as an exception with rich documented diversity in the Neoproterozoic as vase-shaped microfossils (VSMs). While there is general consensus that most of these can be attributed to the Arcellinida lineage in Amoebozoa, it is still unclear whether they can be used as key fossils for interpretation of early eukaryotic evolution. Here, we present a well-resolved phylogenomic reconstruction based on 250 genes, obtained using single-cell transcriptomic techniques from a representative selection of 19 Arcellinid testate amoeba taxa. The robust phylogenetic framework enables deeper interpretations of evolution in this lineage and demanded an updated classification of the group. Additionally, we performed reconstruction of ancestral morphologies, yielding hypothetical ancestors remarkably similar to existing Neoproterozoic VSMs. We demonstrate that major lineages of testate amoebae were already diversified before the Sturtian glaciation (720 mya), supporting the hypothesis that massive eukaryotic diversification took place in the early Neoproterozoic and congruent with the interpretation that VSM are arcellinid testate amoebae.
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| http://dx.doi.org/10.1016/j.cub.2019.01.078 | DOI Listing |
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