Geminigeraceae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of cryptophytes containing the five genera ''

Geminigera ''Geminigera'' /ˌdʒɛmɪnɪˈdʒɛɹə/ is a genus of cryptophyte from the family Geminigeraceae. Named for its unique pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M. ...

'', ''

Guillardia ''Guillardia'' is a genus of marine biflagellate cryptomonad algae with a plastid obtained through secondary endosymbiosis of a red alga. Originally identified in Connecticut by Richard Guillard in the 1960s, ''Guillardia'' only has one descri ...

'', ''Hanusia'', ''Proteomonas'' and ''Teleaulax''. They are characterised by

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

s containing Cr-phycoerythrin 545, and an inner

periplast The periplast is one of three types of cell-covering of three classes of algae. The cryptomonads have the periplast covering. The Dinophyceae have a type called the amphiesma, and the ''Euglena'' covering is the pellicle. Structure The periplast ...

component (IPC) comprising "a sheet or a sheet and multiple plates if diplomorphic". The

nucleomorph Nucleomorphs are small, vestigial eukaryotic nuclei found between the inner and outer pairs of membranes in certain plastids. They are thought to be vestiges of red and green algal nuclei that were engulfed by a larger eukaryote. Because the nucl ...

s are never in the

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

, and there is never a scalariform furrow. The cells do, however, have a long, keeled rhizostyle with lamellae (wings).

References

Cryptomonads Cryptista families Algae families {{Cryptomonad-stub