The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for Prymnesium), are a clade of algae.

Coccolithophore (Coccolithus pelagicus)
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Phylum: Haptista
Subphylum: Haptophytina
Hibberd, 1976 stat. nov. Cavalier-Smith, 2015[1]
Classes & Orders
  • Prymnesiophyta Green & Jordan, 1994
  • Prymnesiophyceae s.l. Casper, 1972 ex Hibberd, 1976
  • Haptophyceae s.l. Christensen, 1962 ex Silva, 1980
  • Haptophyta Hibberd, 1976

The names Haptophyceae or Prymnesiophyceae are sometimes used instead.[2][3][4] This ending implies classification at the class rank rather than as a division. Although the phylogenetics of this group has become much better understood in recent years, there remains some dispute over which rank is most appropriate.


Cell scheme. 1-haptonema, 2-flagella, 3-mitochondrion, 4-Golgi apparatus, 5-nucleus, 6-scales, 7-chrysolaminarin vacuole, 8-plastid, 9-ribosomes, 10-stigma, 11-endoplasmic reticulum, 12-chloroplast endoplasmic reticulum, 13-pyrenoid, 14-thylakoids.

The chloroplasts are pigmented similarly to those of the heterokonts,[5] but the structure of the rest of the cell is different, so it may be that they are a separate line whose chloroplasts are derived from similar red algal endosymbionts.

The cells typically have two slightly unequal flagella, both of which are smooth, and a unique organelle called a haptonema, which is superficially similar to a flagellum but differs in the arrangement of microtubules and in its use. The name comes from the Greek hapsis, touch, and nema, round thread. The mitochondria have tubular cristae.



The best-known haptophytes are coccolithophores, which make up 673 of the 762 described haptophyte species,[6] and have an exoskeleton of calcareous plates called coccoliths. Coccolithophores are some of the most abundant marine phytoplankton, especially in the open ocean, and are extremely abundant as microfossils, forming chalk deposits. Other planktonic haptophytes of note include Chrysochromulina and Prymnesium, which periodically form toxic marine algal blooms, and Phaeocystis, blooms of which can produce unpleasant foam which often accumulates on beaches.[7]

Haptophytes are economically important, as species such as Pavlova lutheri and Isochrysis sp. are widely used in the aquaculture industry to feed oyster and shrimp larvae. They contain a large amount of polyunsaturated fatty acids such as docosahexaenoic acid (DHA), stearidonic acid and alpha-linolenic acid.[8] Tisochrysis lutea contains betain lipids and phospholipids.[9]



The haptophytes were first placed in the class Chrysophyceae (golden algae), but ultrastructural data have provided evidence to classify them separately.[10] Both molecular and morphological evidence supports their division into five orders; coccolithophores make up the Isochrysidales and Coccolithales. Very small (2-3μm) uncultured pico-prymnesiophytes are ecologically important.[7]

Haptophytes was discussed to be closely related to cryptomonads.[11]

Haptophytes are closely related to the SAR clade.[12]

Subphylum Haptophytina Cavalier-Smith 2015 [Haptophyta Hibberd 1976 sensu Ruggerio et al. 2015][13]


  1. ^ Cavalier-Smith, Thomas (2017). "Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences". Protoplasma. 255 (1): 297–357. doi:10.1007/s00709-017-1147-3. PMC 5756292. PMID 28875267. S2CID 19939172.
  2. ^ "Haptophyta". NCBI taxonomy database. National Center for Biotechnology Information, U.S. National Library of Medicine.
  3. ^ Satoh M, Iwamoto K, Suzuki I, Shiraiwa Y (2009). "Cold stress stimulates intracellular calcification by the coccolithophore, Emiliania huxleyi (Haptophyceae) under phosphate-deficient conditions". Marine Biotechnology. 11 (3): 327–33. doi:10.1007/s10126-008-9147-0. hdl:2241/104412. PMID 18830665. S2CID 18014503.
  4. ^ "ITIS Standard Report". Retrieved 19 July 2014.
  5. ^ Andersen RA (October 2004). "Biology and systematics of heterokont and haptophyte algae". American Journal of Botany. 91 (10): 1508–22. doi:10.3732/ajb.91.10.1508. PMID 21652306.
  6. ^ "Haptophyta". Algaebase. Archived from the original on 2021-02-18. Retrieved 2019-10-27.
  7. ^ a b Cuvelier ML, Allen AE, Monier A, McCrow JP, Messié M, Tringe SG, et al. (August 2010). "Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton". Proceedings of the National Academy of Sciences of the United States of America. 107 (33): 14679–84. Bibcode:2010PNAS..10714679C. doi:10.1073/pnas.1001665107. PMC 2930470. PMID 20668244.
  8. ^ Renaud SM, Zhou HC, Parry DL, Thinh LV, Woo KC (1995). "Effect of temperature on the growth, total lipid content and fatty acid composition of recently isolated tropical microalgae Isochrysis sp., Nitzschia closterium, Nitzschia paleacea, and commercial species Isochrysis sp. (clone T.ISO)". Journal of Applied Phycology. 7 (6): 595–602. doi:10.1007/BF00003948. S2CID 206766536.
  9. ^ Kato M, Sakai M, Adachi K, Ikemoto H, Sano H (1996). "Distribution of betaine lipids in marine algae". Phytochemistry. 42 (5): 1341–5. doi:10.1016/0031-9422(96)00115-X.
  10. ^ Medlin LK (1997). "Phylogenetic relationships of the 'golden algae' (Haptophytes, heterokont chromophytes) and their plastids". Origins of Algae and their Plastids (PDF). Plant Systematics and Evolution. Vol. 11. pp. 187–219. doi:10.1007/978-3-7091-6542-3_11. ISBN 978-3-211-83035-2. Archived (PDF) from the original on 2012-03-17.
  11. ^ Reeb VC, Peglar MT, Yoon HS, Bai JR, Wu M, Shiu P, et al. (October 2009). "Interrelationships of chromalveolates within a broadly sampled tree of photosynthetic protists". Molecular Phylogenetics and Evolution. 53 (1): 202–11. doi:10.1016/j.ympev.2009.04.012. PMID 19398025.
  12. ^ Parfrey LW, Lahr DJ, Knoll AH, Katz LA (August 2011). "Estimating the timing of early eukaryotic diversification with multigene molecular clocks". Proceedings of the National Academy of Sciences of the United States of America. 108 (33): 13624–9. Bibcode:2011PNAS..10813624P. doi:10.1073/pnas.1110633108. PMC 3158185. PMID 21810989.
  13. ^ Guiry MD (2016), AlgaeBase, World-wide electronic publication, National University of Ireland, Galway, retrieved 25 October 2016