The development of viable and nutritive embryos in the direct developing gastropod Crepidula navicella
Bibliographic record
Abstract
Adelphophagy occurs when encapsulated embryos complete development by feeding on their developing siblings, which are known as nutritive embryos. Nutritive embryos are found in a variety of animal groups, and are especially common in some groups of marine invertebrates. Although they have evolved numerous times independently in the calyptraeid gastropods, adelphophagic development with nutritive embryos has not been described in detail. Using light microscopy and time-lapse imaging of laboratory-reared embryos, we describe the development of Crepidula navicella, a direct developer with nutritive embryos that cleave and gastrulate. Early stages of nutritive and viable embryos do not show any obvious morphological differences, but do show asynchrony in early cleavage among embryos from the same capsule. We discovered that two classes of nutritive embryos are produced; gastrula-like nutritive embryos, which arrest after gastrulation, and post-gastrula-like nutritive embryos that are more variable in morphology, and show evidence of minor differentiation. This study provides a framework for future research on the developmental and molecular mechanisms of nutritive embryo development of C. navicella, which will allow us to address the role of nutritive embryos in the origins of developmental polyphenisms. Careful description of the developmental sequence is necessary before adaptive hypotheses can be addressed, and comparisons with other taxa can be made. Understanding the different ways that embryos and their development are disrupted to produce nutritive embryos will provide important insights into the normal process of development.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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".