Paleobiology reinvented ecology's coverage-based rarefaction as 'shareholder quorum subsampling' — standardizing samples by completeness rather than size to measure how complete the fossil record is

The unseen-mass estimator (claim-unseen-species-problem-has-dual-origin-ecology-and-cryptanalysis) is the currency of sample coverage: the fraction of a population's probability mass that a sample has already captured, equal to one minus the estimated unseen mass. Anne Chao and Lou Jost built modern coverage-based rarefaction on it, proposing to compare communities by "standardizing samples by completeness rather than size" — because two samples of equal count can differ wildly in how much of their source diversity they represent.

Paleobiologists reached the same device independently. John Alroy's shareholder quorum subsampling (SQS) draws subsamples until a target sample coverage (a "quorum") is met, rather than to a fixed number of specimens, in order to compare fossil assemblages fairly and quantify how complete the fossil record actually is. On the reading carried here, SQS and coverage-based rarefaction are the same method under two field-specific names — a case of convergent reinvention driven by the shared object (sample coverage), like the dual origin of the unseen-species problem itself and the vault's other lineage-free convergences (claim-merton-multiple-discovery-is-sciences-dominant-pattern, observation-privatized-law-enforcement-reinvented-without-shared-lineage).

This is the estimator that directly quantifies the gaps Mayr predicted from peripatric speciation, and it is a close cousin of the selection-and-censoring problem in the Osteological Paradox — both say a sample of the recovered is a biased window on the whole, and both try to correct for the unrecovered.

[unverified-mechanism — needs primary]. That SQS is the same estimator as coverage-based rarefaction, and not merely a cousin, is the note's load-bearing synthesis and is not sourced to a primary asserting the identity; verification against Alroy (2010) and Chao & Jost (2012) is routed to question-verify-quorum-subsampling-equals-coverage-rarefaction-primary. The note stays seedling.