THE NEOICHNOLOGY OF A SEMI-TERRESTRIAL FISH: MUDSKIPPER TRACKWAYS IN MUD-DOMINATED AND SAND-DOMINATED SUBSTRATES
Bibliographic record
Abstract
Abstract Amphibious fishes, with varying degrees of terrestriality, occur in a broad variety of marginal lacustrine and marginal marine settings. Most of these rely on axially driven locomotion (tail and torso bending) in terrestrial movement. Oxudercid gobiids (mudskippers) are distinctive in that their normal terrestrial locomotion is driven primarily by a pulling motion of their pectoral fins resulting in movement termed ‘crutching’. This contribution is focused on the traces emplaced in sand and mud by mudskippers, formed during the locomotory activity of the two most terrestrialized mudskipper genera: Periophthalmus and Periophthalmodon. The traces produced were compared with Devonian ichnofossils in order to frame the discussion of the nature and timing of the earliest vertebrate invasion of terrestrial realms. Mudskipper traces emplaced by large (> 20 cm body length) Periophthalmodon in subaerial, wet, but unsaturated mud produced exceptionally distinctive traces. These traces are characterized by distinct central tail and body grooves, bordered by small distinct pelvic fin traces and larger, arcuate pectoral fin traces. Fin traces in mud substrates commonly retain discrete fin ray impressions. The unique crutching motion results in an approximately symmetrical trace, with paired fin traces on each side of the central grooves. Traces made by smaller Periophthalmus may look similar or may be less distinctive due to the lighter weight of the animals. Traces made in sand may lack pelvic fin impressions and, in some cases may be limited to the central body groove. Mudskipper locomotion traces are similar to the arthropod ichnogenera Siskemia and Stiaria. We note the similarity of some mudskipper tracks to some trackways previously inferred to be made by tetrapods. Assessing the traces that modern amphibious fishes make can inform the search for similar behaviors recorded by Devonian traces and by traces made by previously unrecognized amphibious fishes throughout the post-Devonian interval.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".