Early fossil eukaryotes were benthic aerobes
Data files
Apr 16, 2026 version files 461.08 KB
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README.md
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Supp_Table_1_unformat_for_DRYAD_fossil_occurrences.csv
79.08 KB
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Supp_Table_1_unformat_for_DRYAD_Geochem_data.csv
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Supp_Table_1_unformat_for_DRYAD_Matrices_for_stats.csv
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Supp_Table_1_unformat_for_DRYAD_Tables_of_occurrences.csv
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Supp_Table_1_updated_Nov3__2025.xlsx
248.82 KB
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Supp_Table_2-_Taxa_and_descriptions.xlsx
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Abstract
All complex life on Earth is descended from a single-celled eukaryotic ancestor that lived more than a billion years ago. Although the timing and environmental context of eukaryogenesis, the prolonged origin and evolution of the eukaryotic cell, are poorly constrained, the geological record offers considerable insight. Through integrated paleontological, sedimentological, and geochemical analyses, we reconstruct the habitats of the oldest known (ca. 1.75–1.4 billion-year-old; Ga) fossil eukaryotes. These data show that although eukaryote microfossils are found in samples deposited in a range of marine environments from coastal to offshore, they are almost entirely restricted to settings with oxygenated bottom waters. This distribution suggests that these organisms were aerobic and, given their size and morphological complexity, likely possessed mitochondria by this time. Further, the absence of eukaryotes from otherwise fossiliferous samples that record bottom water anoxia suggests a benthic habit, since planktonic eukaryotes would be expected to have been deposited in those settings.
Dataset DOI: 10.5061/dryad.1vhhmgr8n
Description of the data and file structure
Table 1 includes occurrence data for organic-walled microfossils recovered from fine grained siliciclastic rocks of the Paleoproterozoic-Mesoproterozoic units in the McArthur and Birrindudu basins of northern Australia. Rock samples were collected from eight drillcores stored by the Northern Territory Geological Survey in Darwin, NT. The table indicates the drillcore name, sample depth, group and formation names, the occurrences of organic walled microfossil species, subdivided as likely to have been eukaryotic or not, and redox, trace element and depositional setting data. Additional tabs in the workbook sort fossil occurrences according to redox state and species or group occurrences.
Table 2 provides descriptions of species characters, whether those species are considered eukaryotic or not and references to published literature.
Files and variables
File: Supp_Table_2-_Taxa_and_descriptions.xlsx
Description:
Variables
for Likely Eukaryotes, Likely Prokaryotes and Taxa of Equivocal Affinity
- Taxon = species identified
- Description = description of the morphological character of that species that suggests a eukaryotic affinity
- References in support of affinity = references to published literature in support of the assigned affinity
Second sheet lists cited references including full bibliographic reference
File: Supp_Table_1_updated_Nov3__2025.xlsx
Description: this is the formatted excel version of Table 1, which is also included as multiple CSV files curated here as well. Formatting includes formulas for occurrence matrices used in statistical analyses in published paper.
File: Supp_Table_1_unformat_for_DRYAD_Geochem_data.csv
Description:
Variables
- Basin: either Birrindudu or McArthur basin of Northern Territory, Australia
- Drill Hole: name of drill core
- Depth: sample depth
- Group: geological group
- Formation: geological formation
- TOC wt. %:
- SiO2 wt. %:
- Al2O3 wt. %:
- Fe2O3(T) wt. %:
- MnO wt. %:
- MgO wt. %:
- CaO wt. %:
- Na2O wt. %:
- K2O wt. %:
- TiO2 wt. %:
- P2O5 wt. %:
- V2O5 wt. %:
- LOI:
- Total:
- Fe-Carb wt. %:
- Fe-Ox wt. %:
- Fe-Mag wt. %:
- Fe-Pyrite wt. %:
- Fe-HR wt. %:
- Ti ppm:
- V ppm:
- Cr ppm:
- Co ppm:
- Ni ppm:
- Cu ppm:
- Zn ppm:
- Ga ppm:
- Sr ppm:
- Y ppm:
- Nb ppm:
- Mo ppm:
- W ppm:
- Pb ppm:
- Th ppm:
- U ppm:
File: Supp_Table_1_unformat_for_DRYAD_Matrices_for_stats.csv
Description:
Variables
- number of occurrences of eukaryotic species according to oxic or anoxic nature of setting
File: Supp_Table_1_unformat_for_DRYAD_fossil_occurrences.csv
Description: Main fossil data table. samples indicated by drillcore name and depth, basin, group and formation name. If specimens of given species were recovered in that sample, the number of specimens is recorded in the cell. Blank cells indicate no specimens of that species were recovered in that sample. Redox interpretation provided for each sample. Interpretation is based on data provided in geochemical data table.
Variables
- Basin
- Drill Hole
- Group
- Formation
- Sample Depth
- Analysed for fossils?
- Analysed for redox and fossils?
- Environment (2 = coastal, 3 = lagoonal, 4 = shoreface, 5 = offshore)
- Redox–env
- Redox–env (fossiliferous only)
- Redox
- Barren
- # taxa total any (now includes fragments)
- fragments but noting IDable
- # Likely Eukaryote Taxa
- samples with any mat-formers (Oscillatoriopsis sp.and Siphonophycus sp.)
- Samples with any prokaryote taxa (Siphonophycus spp., Oscillatoriopsis sp., Tortunema spp., Eomicrocystis spp., Synsphaeridium spp.)
- Samples with big leios (L. jacutica and L. tenuissima)
- Samples with little leios (L. crassa and L. minutissima)
- Samples with any leiosphaerids
- Samples with equivocal taxa (Leiosphaeridia spp., Simia, Pterospermopsimorpha, Schizofusa, Plicatidium, Navifusa, S. colonialica, Cucumiforma, Germinosphaera, tubes)
- # Prokaryote or Ambiguous Taxa
- Satka favosa
- Tappania plana
- Valeria lophostriata
- Kamolineata elongata
- Spiromorpha segmentata
- cf. Dictyosphaera macroreticulata
- Jixiania lineata
- Gigantosphaera fibratum
- Gigantosphaeridium floccosum
- Limbunyasphaera operculata
- Birrindudutuba brigandinia
- Siphonoseptum bombycinum
- New, unnamed platey species
- Filinexum torsivum
- Synsphaeridium spp.
- Oscillatoriopsis spp.
- Tortunema spp.
- Eomicrocystis spp.
- Siphonophycus spp.
- Leiosphaeridia crassa
- Leiosphaeridia minutissima
- Leiosphaeridia jacutica
- Leiosphaeridia tenuissima
- Simia spp.
- Pterospermopsimorpha spp.
- New, unnamed tubes with closed ends
- Schizofusa sinica
- Plicatidium spp.
- Navifusa spp.
- Squamosphaera colonialica
- Cucumiforma sp.
- Germinosphaera sp.
File: Supp_Table_1_unformat_for_DRYAD_Tables_of_occurrences.csv
Description: fossil occurrences sorted by redox state and depositional setting of sample. Raw numbers and percentages
Variables
- Samples by redox state
- All samples:
- Samples with paleo study:
- Samples with any fossils- incl fragments:
- Samples with eukaryotes:
- Settings:
Code/software
excel for formatted file but same data are presented in csv files
Access information
Data was derived from the following sources:
- original data except as cited with full references in tables