Developmental transformations in a normal series of embryos of the sea lamprey <i>Petromyzon marinus</i> (linnaeus)
Bibliographic record
Abstract
Lamprey development is of interest to evolutionary biologists because it can inform our understanding of primitive vertebrate developmental patterns. In this study, we describe and illustrate some of the principle landmarks of organogenesis in the embryonic sea lamprey Petromyzon marinus L. at different chronological ages. We examined 63 fixed embryos spanning Piavis developmental stages 11-18+ (5-70 days postfertilization) by gross observation and histology. This period begins at late neurulation stages and ends with the formation of the larva (ammocoete). A significant difference with some previous accounts is that the anus develops not from a persistent blastopore, but by secondary canalization and proctodeum formation at the former site of the blastopore. Further, we show that the ciliated bands of the pharyngeal roof originate in the esophagus, distinguishing it from the intestine. We clarify the epithelialization of the gut, showing that the secondary gut cavity is progressively epithelialized from each end. We identify possible germ cells in the coelomic and cloacal walls. Balfour's "subnotochordal rod" is lacking in our specimens; we suggest that he may have misinterpreted the corpus adiposum. Our study is of potential value to the growing number of biologists interested in lamprey development and provides a character set that will be used : 1) in a phylogenetic study of vertebrate development, and 2) to prepare a staging series for the lamprey based on parsimony analysis.
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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 | 0.001 | 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) | 0.001 | 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".