Niche partitioning and limited mobility characterise Middle Pleistocene kangaroos from eastern Australia
Bibliographic record
Abstract
Australia's Quaternary fossil record is characterised by a high diversity of macropodid taxa. Based on fossil faunal assemblages, it has been hypothesised many macropodids lived in sympatry during the Pleistocene, however, local geographic and dietary overlap is equivocal due to taphonomic uncertainty. Modern macropodid species rarely exhibit sympatry, suggesting anthropogenic or environmental changes may have disrupted these communities. Using Sr and C isotopes, we reconstruct foraging ranges and dietary preferences of several fossil macropodid lineages recovered in Middle Pleistocene cave deposits, at Mount Etna Caves, central eastern Queensland, Australia. Our results show that most macropodids, baring a single Petrogale potentially dispersing >60 km, had limited foraging ranges and remained within 15 km of the fossil site. Moderate to large scale dispersal in individual Petrogale mirrors male-biased dispersal observed in some modern Petrogale populations indicating some individuals have the propensity to move between isolated colonies when corridors for dispersal are present. Smaller macropodids show dietary preferences similar to modern counterparts, while Protemnodon exhibit a division between C 3 /C 4 intake, potentially indicating species-level differences. The analysis of geographic range and diet of this fossil assemblage reveals that macropodids partitioned on the landscape around the cave with a C 3 -dominant community – comprised of Protemnodon, Petrogale, and Thylogale – to the northwest, and a C 4 -dominant grassland community – comprised of Notamacropus and isolated members of Protemnodon and Petrogale – to the south. Therefore, we conclude, that although faunal assemblages alone suggest a larger number of macropodids living in sympatry, isotopic proxies uncover complex habitat partitioning between C 3 and C 4 environments around Mount Etna Caves.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".