Hacrobia | |
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The coccolithophore Gephyrocapsa oceanica | |
Scientific classification ![]() (obsolete as its monophyly is doubtful) | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Kingdom: | Chromista |
Subkingdom: | Hacrobia Okamoto et al., 2009 |
Groups | |
Synonyms | |
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The cryptomonads-haptophytes assemblage is a proposed but disputed monophyletic grouping [1] of unicellular eukaryotes that are not included in the SAR supergroup. Several alternative names have been used for the group, including Hacrobia (derived from "ha-" referring to Haptophyta, "-cr-" referring to cryptomonads, and "-bia" as a general suffix referring to life); [2] CCTH (standing for Cryptophyta, Centrohelida, Telonemia and Haptophyta); [3] and "Eukaryomonadae". [4]
As of February 2012 [update] , it is unclear whether this group is monophyletic or not; results of phylogenetic studies are "often dependent on the selection of taxa and gene data set". [3] Two 2012 studies produced opposite results. [3] [5]
In the past, heterokonts, haptophytes, and cryptomonads have sometimes been grouped together in a group known as chromists. [6] Though the heterokonts are now split out, Cryptophyta and Haptophyta are considered in some studies to be closely related [7] [8] (and are sometimes simply referred to as the "Cryptophyta+Haptophyta" group). [9] A 2009 paper suggested that the Telonemia and centrohelids may form a clade with the cryptophytes and haptophytes. [10] The picobiliphytes may belong in this group but are too poorly known to be classified with confidence. [2]
Several recent studies have concluded that Haptophyta and Cryptophyta do not form a monophyletic group. [11] The former are a sister group to the SAR group, the latter cluster with the Archaeplastida (plants in the broad sense). [5] As of February 2012 [update] , it remains unclear whether the Hacrobia forms a monophyletic group. [3]
Another study [12] suggested the following arrangement: centrohelids are related to haptophytes and form the clade Haptista; Haptista is the sister group to SAR; Cryptista are related to Archaeplastida; and Haptista + SAR is the sister clade to Cryptista + Archaeplastida.
Based on work done by Silar 2016. [13] [14]
Hacrobia |
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