Warnowiaceae
![An image of a single cell featuring a large nucleus and an ocelloid, which is composed of a roundish "lens" and a darkly pigmented disc-shaped retinal body.](/Images/godic/202502/20/Bmc_evol_bio_hoppenrath_proterythropsis_ocelloid_fig1a5340.png")
![Light micrograph of a cell, translucent brown, with lighter-stained nucleus in center and ocelloid visible at lower right as a light region (hyalosome) next to a dark region (retinal body).](/Images/godic/202502/20/Bmc_evol_bio_hoppenrath_Nematodinium_ocelloid_fig1m5340.png")
![Light micrograph of a cell, translucent with purple borders, with an ocelloid visible at lower right.](/Images/godic/202502/20/Bmc_evol_bio_hoppenrath_Warnowia_ocelloid_fig1g5340.png")
The Warnowiaceae are a family of athecate dinoflagellates (a diverse group of unicellular eukaryotes). Members of the family are known as warnowiids. The family is best known for a light-sensitive subcellular structure known as the ocelloid, a highly complex arrangement of organelles with a structure directly analogous to the eyes of multicellular organisms. The ocelloid has been shown to be composed of multiple types of endosymbionts, namely mitochondria and at least one type of plastid.