Classifications
The species now placed in the Xanthophyceae were formerly included in the Chlorophyceae. 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, as order Heterochloridina (e.g., Doflein and Reichenow, 1927-1929), as class Xanthomonadina, with orders Heterochloridea and Rhizochloridea (e.g., Deflandre, 1956), as order Heterochlorida (e.g., Hall, 1953, Honigberg et al., 1964), as order Heteromonadida (e.g., Leedale, 1983), or as subclass Heterochloridia (e.g., Puytorac et al., 1987). 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: * '' Dictyosphaeriopsis'' * '' Groenlandiella'' * '' Halosphaeropsis'' * '' Pelagocystis'' * '' Polyedrium'' * '' Pseudopleurochloris'' * '' Raphidosphaera'' * '' Sphaerochloris'' * '' Tiresias'' * Order Botrydiales Schaffner 1922 ** Family Botrydiaceae Rabenhorst 1863 *** '' Asterosiphon'' *** '' Botrydium'' *** '' Polychloris'' * Order Mischococcales Fritsch 1927 ** Family Botrydiopsidaceae Hibberd 1980 *** '' Botrydiopsis'' *** '' Excentrochloris'' *** '' Perone'' ** Family Botryochloridaceae Pascher 1938 *** '' Botryochloris'' *** '' Chlorellidiopsis'' *** '' Chlorellidium'' *** '' Ducellieria'' *** '' Heterodesmus'' *** '' Ilsteria'' *** '' Raphidiella'' *** '' Sphaerosorus'' *** '' Tetraktis'' ** Family Centritractaceae Pascher 1937 *** '' Bumilleriopsis'' *** '' Centritractus'' *** '' Pseudotetraëdron'' ** Family Characiopsidaceae Pascher 1938 *** '' Characiopsis'' *** '' Chlorokoryne'' *** '' Chlorothecium'' *** '' Chytridiochloris'' *** '' Dioxys'' *** '' Harpochytrium'' *** '' Hemisphaerella'' *** '' Lutherella'' *** '' Peroniella'' ** Family Chloropediaceae Pascher 1931 *** '' Chloropedia'' ** Family Gloeobotrydaceae Pascher 1937 *** '' Chlorosaccus'' *** '' Asterogloea'' *** '' Dictyosphaeriopsis'' *** '' Gaumiella'' *** '' Gloeobotrys'' *** '' Gloeoskene'' *** '' Gloeosphaeridium'' *** '' Merismogloea'' ** Family Gloeopodiaceae Pascher 1938 *** '' Gloeopodium'' ** Family Mischococcaceae Pascher 1912 *** '' Mischococcus'' ** Family Ophiocytiaceae Lemmermann 1899 *** '' Ophiocytium'' ** Family Pleurochloridaceae Pascher 1937 *** '' Acanthochloris'' *** '' Actinellipsoidion'' *** '' Arachnochloris'' *** '' Aulakochloris'' *** '' Bracchiogonium'' *** '' Chlorallanthus'' *** '' Chlorapion'' *** '' Chlorarkys'' *** '' Chloridella'' *** '' Chlorocloster'' *** '' Chlorogibba'' *** '' Diachros'' *** '' Endochloridion'' *** '' Isthmochloron'' *** '' Keriosphaera'' *** '' Leuvenia'' *** '' Meringosphaera'' *** '' Monallanthus'' *** '' Monodus'' *** '' Nephrodiella'' *** '' Osterhoutia'' *** '' Pleurochloridella'' *** '' Pleurochloris'' *** '' Pleurogaster'' *** '' Polyedriella'' *** '' Polygoniochloris'' *** '' Prismatella'' *** '' Pseudogoniochloris'' *** '' Pseudopolyedriopsis'' *** '' Rhomboidella '' *** '' Schilleriella'' *** '' Skiadosphaera'' *** '' Sklerochlamys'' *** '' Tetraplektron'' *** '' Trachychloron'' ** Family Trypanochloridaceae Geitler ex Pascher 1938 *** '' Trypanochloris'' * Order Rhizochloridales Pascher 1925 *** '' Garciamyxa'' *** '' Herreramyxa'' *** '' Requejomyxa'' ** Family Myxochloridaceae Pascher 1937 *** '' Myxochloris'' ** Family Rhizochloridaceae Pascher 1925 *** '' Aldavemyxa'' *** '' Heterocalycina'' *** '' Rhizochloris'' ** Family Stipitococcaceae Pascher ex Smith 1933 *** '' Rhizolekane'' *** '' Stipitococcus'' *** '' Stipitoporos'' * Order Tribonematales Pascher 1939 ** Family Heterodendraceae Pascher 1939 *** '' Heterodendron'' ** Family Heteropediaceae Hibberd 1982 *** '' Capitulariella'' *** '' Chaetopedia'' *** '' Heterococcus'' *** '' Heteropedia'' *** '' Sphagnoikos'' ** Family Neonemataceae Ettl 1977 *** '' Neonema'' ** Family Tribonemataceae West 1904 *** '' Brachynematella'' *** '' Bumilleria'' *** '' Tribonema'' ** Family Xanthonemataceae Silva 1980 *** ?'' Hormotheca'' *** '' Heterotrichella'' *** '' Xanthonema'' * Order Vaucheriales Nägeli ex Bohlin 1901Christensen, T. 1987. ''Seaweeds of the British Isles.'' Volume 4 Tribophyceae (Xanthophyceae). British Museum (Natural History), London ** Family Vaucheriaceae (Gray) Dumortier 1822 *** '' Pseudodichotomosiphon'' *** '' Vaucheria'' *** '' Vaucheriella''Lüther (1899)
Classification according to Lüther (1899): * Class Heterokontae ** Order Chloromonadales ** Order ConfervalesPascher (1912)
Classification according to Pascher (1912): * Heterokontae ** Heterochloridales ** Heterocapsales ** Heterococcales ** Heterotrichales ** HeterosiphonalesFritsch (1935)
Fritsch (1935) recognizes the following orders in the class Xanthophyceae: *Order Heterochloridales ** Suborder Heterochlorineae *** Family Heterochloridaceae (e.g., '' Heterochloris'') ** Suborder Heterocapsineae *** Family Heterocapsaceae (e.g., '' Chlorogloea'') ** Suborder Heterodendrineae *** Family Mischococcaceae (e.g., '' Mischococcus'') ** Suborder Heterorhizidineae *** Family Heterorhizidaceae (e.g., '' Rhizolekane'') *Order Heterococcales ** Family Halosphaeraceae (e.g., ''Smith (1938)
In the classification of Smith (1938), there are six orders in the class Xanthophyceae, placed in the division Chrysophyta: *Order Heterochloridales (e.g., '' Chlorochromonas'') *Order Rhizochloridales (e.g., '' Chlorarachnion'') *Order Heterocapsales (e.g., '' Chlorosaccus'') *Order Heterotrichales (e.g., '' Tribonema'') *Order Heterococcales (e.g., '' Botrydiopsis'') *Order Heterosiphonales (e.g., '' Botrydium'')Pascher (1939)
Pascher (1939) recognizes 6 classes in Heterokontae: *Class Heterochloridineae *Class Rhizochloridineae *Class Hetcrocapsineae *Class Heterococcincae *Class Hetcrotrichineae *Class HeterosiphonineaeCopeland (1956)
Copeland (1956) treated the group as order Vaucheriacea: * Kingdom Protoctista ** Phylum Phaeophyta *** ClassEttl (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), an updated version of the classic work by Pascher (1939).Maistro et al. (2009)
Informal groups, according to Maistro et al. (2009): * 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): * Tribonematales (genera ''Botrydium, Bumilleriopsis, Characiopsis, Chloromeson, Heterococcus, Ophiocytium, Sphaerosorus, Tribonema, Xanthonema'') * Vaucheriales (genus ''Vaucheria'')See also
*References
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