Abstract
Despite 2.3 million described species, biodiversity knowledge remains incomplete and unevenly distributed. We analysed 20 years of terrestrial mollusc descriptions, categorizing collaborations as domestic (authored by resident researchers only), parachute (foreign researchers only) or mixed (joint collaboration) to assess links between discovery practices, socioeconomic factors, methodological rigour (number of type specimens, morphometric characters, evidence lines and publication length) and accessibility to analytical tools and resources (internal anatomy, molecular biology and taxonomic revisions). Global South harboured 88.6% of parachute discoveries, with resident researchers involved in 33.3% of total descriptions. Exclusionary practices resulted in lower first-authorship rates for Global South researchers and frequent omission of fieldwork personnel. Collaborations were asymmetrical: nearly 90% of Global South-led studies included Northern researchers, but only 8% of Northern-led studies included Southern partners. Economic power correlated with absolute and relative parachute discovery outputs, while mixed collaborations improved Global South access to analytical tools-although their descriptions remained less comprehensive. Parachute discoveries in the Global South showed lower methodological rigour, underscoring the cost of excluding local expertise. Taxonomic revisions, which were 89% led by the Global North, further reflected resource disparities. Equitable international collaborations prioritizing local capacity-building are crucial for achieving global biodiversity knowledge and advancing conservation goals.