Editing Chloroplast (section)

=== Haptophyte-derived chloroplasts ===
[[File:Karenia brevis.jpg|thumb|upright|''[[Karenia brevis]]'' is a [[fucoxanthin]]-containing dynophyte responsible for [[algal bloom]]s called "[[red tide]]s".<ref name="Hackett-2004" />]]

The [[fucoxanthin]] dinophyte lineages (including ''[[Karlodinium]]'' and ''[[Karenia (dinoflagellate)|Karenia]]'')<ref name="Keeling-2010" /> lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a [[haptophyte]] endosymbiont, making these tertiary plastids. ''[[Karlodinium]]'' and ''[[Karenia (dinoflagellate)|Karenia]]'' probably took up different endosymbionts.<ref name="Keeling-2010" /> Because the haptophyte chloroplast has four membranes, tertiary endosymbiosis would be expected to create a six membraned chloroplast, adding the haptophyte's [[cell membrane]] and the dinophyte's [[phagosomal vacuole]].<ref name="Tengs-2000" /> However, the haptophyte was heavily reduced, stripped of a few membranes and its nucleus, leaving only its chloroplast (with its original double membrane), and possibly one or two additional membranes around it.<ref name="Keeling-2010" /><ref name="Tengs-2000">{{cite journal | vauthors=Tengs T, Dahlberg OJ, Shalchian-Tabrizi K, Klaveness D, Rudi K, Delwiche CF, Jakobsen KS | title=Phylogenetic analyses indicate that the 19'Hexanoyloxy-fucoxanthin-containing dinoflagellates have tertiary plastids of haptophyte origin | journal=Molecular Biology and Evolution | volume=17 | issue=5 | pages=718–29 | date=May 2000 | pmid=10779532 | doi=10.1093/oxfordjournals.molbev.a026350 | author-link4=Dag Klaveness (limnologist) | doi-access=free }}</ref>

Fucoxanthin-containing chloroplasts are characterized by having the pigment [[fucoxanthin]] (actually [[19′-hexanoyloxy-fucoxanthin]] and/or [[19′-butanoyloxy-fucoxanthin]]) and no peridinin. Fucoxanthin is also found in haptophyte chloroplasts, providing evidence of ancestry.<ref name="Hackett-2004" />