A redescription of a rare chordate, <i>Metaspriggina Walcotti</i> Simonetta and Insom, from the Burgess Shale (Middle Cambrian), British Columbia, Canada
Bibliographic record
Abstract
U ntil Recently, our understanding of the earliest history of the fish has been fragmentary in terms of the fossil record and conjectural with respect to many details of phylogeny. Fortunately, significant new information has become available in recent years, most notably from the discoveries of at least three taxa of agnathan fish from the Lower Cambrian Chengjiang Lagerstätte of Yunnan, China (Shu et al., 1999, 2003; Shu, 2003; see also Hou et al., 2002; Hou et al., 2004, p. 192-193; Zhang and Hou, 2004). Two of the taxa ( Haikouichthys and Zhangjianichthys ) are represented by numerous specimens, but it is noteworthy that amongst the forty-odd Burgess Shale-type occurrences apart from the Chengjiang Lagerstätte, chordates (or indeed cephalochordates and urochordates) are otherwise unknown. The one exception is the Burgess Shale itself, characterized by the rather enigmatic Pikaia gracilens (Conway Morris, 1982, 1998) and the much rarer chordate described herein. Apart from this exceptionally preserved material, the fossil record effectively only begins in the Ordovician (e.g., Sansom et al., 2001, 2005; Sansom and Smith, 2005), in as much putative fish scales from the latest Cambrian (Young et al., 1996) may be better interpreted as arthropodan (see Smith et al., 2001, p. 78). The difficulties of interpreting what is overall an extremely patchy record are further compounded by the fact that the relevance to this early history of the extant agnathan hagfish and lamprey has remained (and indeed to some extent remains) problematic, given the uncertainty as to which of the presumed archaic features have been overprinted by specializations for modes of life that might have had little counterpart in the ancestral forms.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".