Diagnosability without gatekeeping in taxonomy: on the ‘Kaiserian shortfall’

Deprá (2025) raises an important and timely concern regarding the accumulation of formally available zoological names that lack workable diagnoses, a phenomenon he terms “the Kaiserian shortfall”. Few practicing taxonomists would dispute that poorly diagnosed taxa impose substantial costs on systematic research, contributing to instability, redundancy, and the repeated re-examination of material that should already be taxonomically resolved. On this central point, there is a broad agreement: taxa that cannot be reliably recognized undermine the scientific and practical goals of taxonomy (Winston 1999).