Classifications
The species now placed in the Xanthophyceae were formerly included in the Chlorophyceae.[8] In 1899, Lüther created the group Heterokontae for green algae with unequal flagella. Pascher (1914) included the Heterokontae in the Chrysophyta. In 1930, Allorge renamed the group as Xanthophyceae.
The monadoid (unicellular flagellates) and also sometimes the amoeboid species have been included by some authors in the Protozoa or Protista,[9][10] as order Heterochloridina (e.g., Doflein and Reichenow, 1927–1929[11]), as class Xanthomonadina, with orders Heterochloridea and Rhizochloridea (e.g., Deflandre, 1956[12]), as order Heterochlorida (e.g., Hall, 1953,[13] Honigberg et al., 1964[14]), as order Heteromonadida (e.g., Leedale, 1983[15]), or as subclass Heterochloridia (e.g., Puytorac et al., 1987[16]). These groups are called ambiregnal protists, as names for these have been published under either or both of the ICZN and the ICN.
AlgaeBase (2020)
Xanthophyceae have been divided into the following five orders in some classification systems:[17]
Lüther (1899)
Classification according to Lüther (1899):[19][20]
- Class Heterokontae
- Order Chloromonadales
- Order Confervales
Pascher (1912)
Classification according to Pascher (1912):[21]
- Heterokontae
- Heterochloridales
- Heterocapsales
- Heterococcales
- Heterotrichales
- Heterosiphonales
Fritsch (1935)
Fritsch (1935) recognizes the following orders in the class Xanthophyceae:[22]
- Order Heterochloridales
- Order Heterococcales
- Order Heterotrichales
- Order Heterosiphonales
Smith (1938)
In the classification of Smith (1938), there are six orders in the class Xanthophyceae, placed in the division Chrysophyta:
Pascher (1939)
Pascher (1939) recognizes 6 classes in Heterokontae:[23]
- Class Heterochloridineae
- Class Rhizochloridineae
- Class Hetcrocapsineae
- Class Heterococcincae
- Class Hetcrotrichineae
- Class Heterosiphonineae
Copeland (1956)
Copeland (1956) treated the group as order Vaucheriacea:[24]
- Kingdom Protoctista
- Phylum Phaeophyta
- Class Heterokonta
- Order Vaucheriacea
- Family Chlorosaccacea
- Family Mischococcacea
- Family Chlorotheciacea
- Family Botryococcacea
- Family Stipitococcacea
- Family Chloramoebacea
- Family Tribonematacea
- Family Phyllosiphonacea
Ettl (1978), van den Hoek et al. (1995)
In a classification presented by van den Hoek, Mann and Jahns (1995), based on the level of organization of the thallus, there are seven orders:
- Order Chloramoebales (e.g., Chloromeson) - flagellate organisms
- Order Rhizochloridales (e.g., Rhizochloris, Myxochloris) - ameboid organisms
- Order Heterogloeales (e.g., Gloeochloris) - palmelloid (tetrasporal) organisms
- Order Mischococcales (e.g., Chloridella, Botrydiopsis, Characiopsis, Ophiocytium) - coccoid organisms
- Order Tribonematales (e.g., Tribonema, Heterococcus, Heterodendron) - filamentous organization
- Order Botrydiales (e.g., Botrydium) - siphonous organization; sexual reproduction isogamous or anisogamous
- Order Vaucheriales (e.g., Vaucheria) - siphonous organization; sexual reproduction oogamous
These are the same orders of the classification of Ettl (1978),[25] an updated version of the classic work by Pascher (1939). Ultrastructural and molecular studies shows that the Mischococcales might be paraphyletic, and the Tribonematales and Botrydiales polyphyletic,[26] and suggests two orders at most be used until the relationships within the division are sorted.[27]
Maistro et al. (2009)
Informal groups, according to Maistro et al. (2009):[28]
- Botrydiopsalean clade
- Chlorellidialean clade
- Tribonematalean clade
- Vaucherialean clade
Unicellular flagellates, amoeboid and palmelloid taxa were not included in this study.
Adl et al. (2005, 2012)
According to Adl et al. (2005, 2012):[27][29]
- Tribonematales (genera Botrydium, Bumilleriopsis, Characiopsis, Chloromeson, Heterococcus, Ophiocytium, Sphaerosorus, Tribonema, Xanthonema)
- Vaucheriales (genus Vaucheria)
Stipitococcus capense (Rhizochloridales)
Ophiocytium arbusculum (Mischococcales), formerly Sciadium arbuscula
Other genera
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