Chrysochromulina cyathophora is a unicellular marine haptophyte in the genus Chrysochromulina, order Prymnesiales, class Prymnesiophyceae. The specific epithet cyathophora derives from Greek meaning cup-bearing, describing a characteristic cup-shaped element — likely a scale morphology — visible under transmission electron microscopy. Such ultrastructural features are essential for species identification within Chrysochromulina, where species are otherwise morphologically similar at the light microscopy level. C. cyathophora is known from Norwegian coastal marine environments and has also been recorded from Brazilian waters, a distribution pattern shared by several Chrysochromulina species, suggesting either broad Atlantic dispersal or recurrent misidentification across these distant populations. The species occupies the nanoplankton size fraction and is adapted to life in the water column of coastal to open-ocean marine systems. Chrysochromulina species as a group are important contributors to marine primary production, particularly in oligotrophic environments where smaller phytoplankton dominate. They may also practice mixotrophy — ingesting bacteria and small prey alongside photosynthesis — providing metabolic flexibility in nutrient-limited conditions. The life cycle of Chrysochromulina typically involves asexual division, though sexual stages are poorly documented for most species. C. cyathophora has not been assessed under the IUCN Red List framework, carrying a conservation status of Not Evaluated, consistent with the broader treatment of marine microplankton taxa that present significant challenges for population-level assessment and threat evaluation.