Chrysochromulina leadbeateri is a haptophyte microalga named in honor of the British phycologist Irene Leadbeater, recognizing contributions to ultrastructural research on flagellate algae. The species belongs to the family Prymnesiaceae and possesses the characteristic Chrysochromulina cell plan: biflagellate, haptonema-bearing, and covered with organic scales. Scale morphology, analyzed by transmission electron microscopy, provides taxonomically diagnostic characters that distinguish C. leadbeateri from its congeners. The species occurs in marine coastal waters, with records from the North Atlantic region. The genus Chrysochromulina includes some of the most abundant marine nanoflagellates in high-latitude coastal ecosystems, contributing substantially to primary production and bacterial mortality through mixotrophic feeding. Dense blooms of Chrysochromulina species have periodically caused ecological damage in Scandinavian aquaculture, releasing cytotoxic compounds into the water column. C. leadbeateri itself has not been implicated in harmful bloom events. The species has not been formally assessed for conservation status and is listed as Not Evaluated by the IUCN. Its population dynamics and geographic range remain poorly constrained by available survey data.