Mitochondrial DNA variation in an endemic aquatic snail genus, Caldicochlea (Hydrobiidae; Caenogastropoda) in Dalhousie Springs, an Australian arid-zone spring complex
Bibliographic record
Abstract
The gastropod genus Caldicochlea, with two recognized species C. harrisi and C. globosa, is endemic to Dalhousie Springs, an artesian spring system in arid northern South Australia. A previous study using allozymes showed that C. harrisi is found in most of the active outflows but C. globosa is confined to the larger, hotter springs in the northern third of the complex where the species are sympatric and that hybridization may be frequent in only two springs. The evolutionary relationships within Caldicochlea were investigated using 16S ribosomal RNA (16S: 75 sequences) and cytochrome c oxidase I (COI: 27 sequences). Clades corresponding to the two species are seen in both the 16S and COI analyses, the average Kimura 2- parameter distance between the clades being 0.028 ± 0.007 for 16S rRNA and 0.040 ± 0.016 for COI with no evidence that the recognized taxa represent species complexes. Only four of 22 16S haplotypes in C. harrisi were found in more than one spring and only two of 12 in C. globosa. No COI haplotype was found in more than one spring. In one spring where earlier research suggested that interbreeding may occur, all scored DNA sequences belonged to the C. harrisi clade and in the other such spring all scored sequences belonged to the C. globosa clade. The data do not clarify whether the time of primary divergence between the species occurred in situ at Dalhousie Springs. The absence of suitable habitat refugia since the onset of Pleistocene aridity suggests that the species have been sympatric or parapatric over tens of thousands of years, raising questions as to how an incomplete reproductive isolation can be maintained and how both species could persist in such a geographically restricted area.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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 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".