FOSSIL CALIBRATIONS FOR THE ARTHROPOD TREE OF LIFE
Bibliographic record
Abstract
ABSTRACT Fossil age data and molecular sequences are increasingly combined to establish a timescale for the Tree of Life. Arthropods, as the most species-rich and morphologically disparate animal phylum, have received substantial attention, particularly with regard to questions such as the timing of habitat shifts (e.g. terrestrialisation), genome evolution (e.g. gene family duplication and functional evolution), origins of novel characters and behaviours (e.g. wings and flight, venom, silk), biogeography, rate of diversification (e.g. Cambrian explosion, insect coevolution with angiosperms, evolution of crab body plans), and the evolution of arthropod microbiomes. We present herein a series of rigorously vetted calibration fossils for arthropod evolutionary history, taking into account recently published guidelines for best practice in fossil calibration. These are restricted to Palaeozoic and Mesozoic fossils, no deeper than ordinal taxonomic level, nonetheless resulting in 80 fossil calibrations for 102 clades. This work is especially timely owing to the rapid growth of molecular sequence data and the fact that many included fossils have been described within the last five years. This contribution provides a resource for systematists and other biologists interested in deep-time questions in arthropod evolution. ABBREVIATIONS AMNH American Museum of Natural History AMS Australian Museum, Sydney AUGD University of Aberdeen BGR Bundesanstalt fur Geowissenschaften und Rohstoffe, Berlin BMNH The Natural History Museum, London CNU Key Laboratory of Insect Evolutionary & Environmental Change, Capital Normal University, Beijing DE Ulster Museum, Belfast ED Ibaraki University, Mito, Japan FMNH Field Museum of Natural History GMCB Geological Museum of China, Beijing GSC Geological Survey of Canada IRNSB Institut Royal des Sciences Naturelles de Belgique, Brussels KSU Kent State University Ld Musee Fleury, Lodeve, France LWL Landschaftsverband Westfalen-Lippe-Museum fur Naturkunde, Munster MACN Museo Argentino de Ciencias Naturales, Buenos Aires MBA Museum fur Naturkunde, Berlin MCNA Museo de Ciencias Naturales de Alava, Vitoria-Gasteiz, Alava, Spain MCZ Museum of Comparative Zoology, Harvard University MGSB Museo Geologico del Seminario de Barcelona MN Museu Nacional, Rio de Janeiro MNHN Museum national d'Histoire naturelle, Paris NHMUK The Natural History Museum, London NIGP Nanjing Institute of Geology and Palaeontology NMS National Museum of Scotland OUM Oxford University Museum of Natural History PBM Palaobotanik Munster PIN Paleontological Institute, Moscow PRI Paleontological Research Institution, Ithaca ROM Royal Ontario Museum SAM South Australian Museum, Adelaide SM
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.007 | 0.037 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.008 | 0.006 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.011 | 0.003 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".