Cryptomonads
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Cool Facts About Cryptomonads!
Cryptomonads, like many eukaryotic algal lineages, obtained their plastids through the engulfment of a eukaryotic algal endosymbiont (a process known as secondary, or higher-order, endosymbiosis). Most eukaryotic algae eventually completely eliminated the nuclei of their endosymbionts, but Cryptomonads (along with one group of marine algae, the chlorarachniophyte algae), have retained it in the form of a nucleomorph: a small, compact remnant of the endosymbiont’s nucleus (Lane et al., 2006).
Morphology of Cryptomonads
Cryptomonad cells have a flattened and asymmetric shape (Hoef-Emden & Archibald, 2017); this sometimes gives the cells a slipper-shaped appearance. At the anterior (front) end of the cell, there is a depression called a vestibulum, and two flagella arise from the right margin of this depression; as a result of this arrangement, cryptomonad cells rotate around their long axis as they swim (Clay, 2015).
Cryptomonad taxa vary with respect to the combinations of pigments they possess, and therefore exhibit a range of colors, including red, brown, and even blue-green (Clay et al., 1999). Cryptomonas, a common representative genus, is brown to olive-brown in color. Cells may be solitary or may form palmellae, agglomerations of cells suspended within a mucilaginous matrix (Hoef-Emden & Archibald, 2017).
Ecology of Cryptomonads
While cryptomonads inhabit various types of waterbodies, their abundance and diversity is highest in the plankton of temperate lakes (Clay, 2015). Nine genera have been documented in freshwater habitats of North America (Wehr & Sheath, 2015), though Cryptomonas is likely the most abundant freshwater genus (Hoef-Emden & Archibald, 2017). Cryptomonas is regularly seen in water samples collected by NJCWST, and is the only representative genus we have thus far observed.
In addition to freshwater habitats, cryptomonads are also found in brackish and marine waters (Hoef-Emden & Archibald, 2017).
Genera Observed by NJCWST
Cryptomonas
Image Gallery
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Cryptomonas
References
Clay, B. L., Kugrens, P., & Lee, R. E. (1999). A revised classification of the Cryptophyta. Botanical Journal of the Linnean Society, 131(2), 131–151.
Clay, B.L. (2015). Cryptomonads. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Freshwater Algae of North America: Ecology and Classification (2nd ed). Waltham, MA: Elsevier.
Hoef-Emden K. & Archibald J.M. (2017) Cryptophyta (Cryptomonads). In: Archibald J., Simpson A., Slamovits C. (eds) Handbook of the Protists. Springer, Cham. https://doi.org/10.1007/978-3-319-28149-0_35
Lane, C.E., Khan, H., MacKinnon, M., Fong, A., Theophilou, S., & Archibald, J.M. (2006). Insight into the diversity and evolution of the cryptomonad nucleomorph genome. Molecular Biology and Evolution, 23(5), 856–865. https://doi.org/10.1093/molbev/msj066
Wehr, J. D., & Sheath, R. G. (2015). Introduction to the Freshwater Algae. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Freshwater Algae of North America: Ecology and Classification (2nd ed). Waltham, MA: Elsevier.