Latest Cambrian–earliest Ordovician conodonts from far western New South Wales and their biostratigraphical significance
Bibliographic record
Abstract
This report documents the conodonts recovered from the Andersons Tank Limestone Member (new name) and calcareous siltstone lenses within the Scropes Range Formation and from the Kandie Tank Limestone within the Kayrunnera Group of the central-southern Koonenberry Belt in far western New South Wales, Australia. Among 18 identifiable conodont species are two new species, Paltodus simplex sp. nov. and Variabiloconus delicatus sp. nov. The conodonts confirm that the age of the Kandie Tank Limestone extends from the latest Cambrian (Cordylodus proavus Biozone) to Early Ordovician (Chosonodina herfurthi Biozone), partly contemporaneous with the Andersons Tank Limestone Member that ranges from the latest Cambrian Cordylodus proavus Biozone to possibly earliest Ordovician (Cordylodus lindstromi Biozone). Occurrence of the index species Iapetognathus fluctivagus and Iapetonudus ibexensis in the middle part of the Kandie Tank Limestone provides direct correlation to the base of the Ordovician System defined at the Green Point section in western Newfoundland of North America, and to sections in Asia and South America. These new data have significantly improved our current understanding of the Ordovician biostratigraphy in the region and more broadly the geological history and evolution of the eastern Gondwana margin during the early Paleozoic. We provide detailed morphological comparison and formal designation of the lectotypes for the four species (I. fluctivagus, Iapetognathus jilinensis, Iapetognathus landingi and I. ibexensis) critical for defining and globally correlating the basal Ordovician.Zhen Y.Y.* [yong-yi.zhen@regional.nsw.gov.au] and I.G. Percival [ianpercival1952@gmail.com], Geological Survey of New South Wales, W.B. Clarke Geoscience Center, 947–953 Londonderry Road, Londonderry New South Wales 2753, Australia; P.M. Smith [Patrick.Smith@australian.museum], Paleontology Department, Australian Museum Research Institute, 1 William Street, Sydney New Sout Wales 2010, Australia, and School of Natural Sciences, 18 Wally’s Walk, Ground Floor, Macquarie University, Sydney New South Wales 2109, Australia; B.D. Webby [bwebby25@gmail.com], School of Geosciences, University of Sydney, New South Wales 2006, Australia.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".