Land-constrained Monte Carlo baselines for corridor enrichment analysis: correcting coastal jitter bias and testing a proposed transcontinental great circle alignment

Preprint (v9.3) of the manuscript by Elliot Allan, Deep Time Research Institute. Submitted May 5, 2026 to Scientific Reports. This version (v9.3, May 2026) incorporates: pandoc table rebuild producing real editable Word tables with full cell content; seven textual fixes (Tables 6 and 7 now cited in body; voice mix corrected to first-person plural in four locations; FALSIFIED replaced with NOT SUPPORTED in Table 8 cells and legend; bracketed citation removed from abstract; Author Contributions section moved after References); two tables moved to Supplementary Information (Tables S3 and S4); five supplementary figures (S1-S5, Monte Carlo diagnostic plots) added; word count trimmed from 5,755 to 4,475 to meet Sci Rep main-text limit; sequential citation numbering 1–33; title shortened to 20 words to meet Sci Rep guideline; AI disclosure aligned across manuscript and cover letter. All hypotheses, statistics, methods, sample sizes, and conclusions unchanged from v9. Citation audit: all 33 references DOI-verified. Submitted to Scientific Reports. Code and data: https://github.com/thegreatcircledata/great-circle-analysis