DESAFÍOS CONCEPTUALES PARA LA RECONSTRUCCIÓN PALEOECOLÓGICA DE LA MEGAFAUNA PAMPEANA Y LAS CONSECUENCIAS DE SU EXTINCIÓN
Bibliographic record
Abstract
The Pleistocene Pampean Megafauna (PPM) may be considered as the assemblage consisting mainly of large mammals (i.e., bodymass ≥ 45 kg) that inhabited what is currently considered the Pampean Region during the Pleistocene and became extinct near the Pleistocene–Holocene transition. This contribution addresses several conceptual issues that may guide future efforts in its reconstruction and to consider potential consequences of its extinction. First, we approach the concept of megafauna by urging its explicit definition and contextualization in every investigation as a means of avoiding conceptual ambiguity. Second, we call attention to the risks of succumbing too readily to the temptation of employing a simplistic approach that assumes that extinct taxa had virtually the same biological requirements as those of their extant counterparts. We claim that within the PPM the abundance of taxa distantly related to or markedly distinct morphologically from their living counterparts poses significant challenges for understanding their paleobiology. Paleobiological interpretations need not be rigidly phylogenetically restricted, and phylogenetically based interpretations require critical assessment before their application. Third, we consider the paleoecology of the PPM from a metabolic perspective: as it was clearly dominated by allegedly hypometabolic megaherbivores (xenarthrans), there is no clear counterpart among living faunas. Fourth, we call attention to the fact that the loss of the PPM may have left in its wake an enduring but little-recognized legacy on the functioning of the contemporary ecosystem of the Pampean Region. Extinction of the PPM opened an enormous ecological chasm in the herbivore guild during the Holocene that persisted for about 6000 years, until it was filled, at least in part, by herds of cattle introduced since the sixteenth century.
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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 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.003 | 0.024 |
| Scholarly communication | 0.009 | 0.010 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.003 | 0.006 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".