Rhizaria
Sign in to saveThe Rhizaria are a diverse and species-rich clade of mostly unicellular eukaryotes. Except for the chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthetic, but many Foraminifera and Radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, Guttulinopsis vulgaris, a cellular slime mold, has been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon.
Species
Infrakingdom
Habitatmarine, brackish, freshwater
有孔蟲界（学名：Rhizaria）為原生生物的一條主線。它們的形態差別很大，但主要部分均為變形蟲狀（amoeboid）並有絲狀、網狀或小管型支撐的假足。它們部分會製造可能有複雜結構的外殼或骨架，而這些外殼或骨架成為絕大部分的原生動物化石。它們差不多全部都擁有管狀脊的線粒體。有孔蟲界分為三類： 絲足蟲類 - 各種各樣的阿米巴及鞭毛蟲（flagellates），通常擁有絲狀的假足，在土壤十分常見。 有孔蟲門 - 變形蟲狀、擁有網狀假足，通常為海洋的底棲生物（benthos）。 放射蟲門 - 變形蟲狀、擁有軸足（axopods），通常為海洋的浮游生物（plankton） 其他類別有可能被歸入絲足蟲類，但部分分支則較為接近有孔蟲門。她們為Phytomyxea（英语：Phytomyxea）及Ascetosporea（英语：Ascetosporea），分別為植物及動物的寄生生物，與及特別的阿米巴Gromia（英语：Gromia）。有孔蟲界的不同組別主要因為基因上的相似性而被認為是近親。她們亦被認為是絲足蟲類的伸延。有孔蟲界的名稱Rhizaria由Cavalier-Smith在2002年提出，他亦提出了Apusozoa（英语：Apusozoa）及centrohelid的名稱。 目录 1 進化關係 1.1 與其他界別的關係 1.2 歷史上其分類的演化 2 參考資料 3 外部連結 進化關係 現代真核生物分類 與其他界別的關係 有孔蟲界為雙鞭毛生物分支的一部分，亦包含泛植物（Archaeplastida）、囊泡藻（Chromalveolata）、古虫界（Excavata）與及其他較小、未分類的組別例如无根虫门（英语：Apusozoa）（Apusozoa）及Centrohelid。和其他雙鞭毛生物相同，她們均源自擁有兩個鞭毛的真核異養生物（heterotrophic）。亦有想法認為有孔蟲界與古虫界有與其他組別相比，在分支稱為（Cabozoa）中有較深的關係。 歷史上其分類的演化 歷史上很多有孔蟲界的生物因為其機動性及異養性而被認為是動物。但自從五界系統（Five-kingdom system）替代動植物生物的二分法（dichotomy）成為主流後，有孔蟲界被當為原生生物界。接著，卡尔·乌斯（Carl Woese）刊出其三域系統。因為無核生物界（或稱為原核界，Monera）是并系群，分類學者把注意力轉移在真核生物領域及原生生物（Protista）的固有并系群上。經過大量討論後，現在討論仍然持續，有孔蟲界被歸類為有效的單系群分類。 參考資料 Cavalier-Smith, Thomas. The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa. International Jo
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Research
1,631 papers- Rhizaria.Current biology : CB · 2014
- The Vampyrellid Amoebae (Vampyrellida, Rhizaria).Protist · 2022
- Paulinella chromatophora.Current biology : CB · 2021
- WeiTsing, a pericycle-expressed ion channel, safeguards the stele to confer clubroot resistance.Cell · 2023
- Algae.Current biology : CB · 2014
via PubMed
Wikidata facts
Show 4 more facts
- P105
- infrakingdom
- P13318
- sexual reproduction
- P523
- Neoproterozoic
via Wikidata · CC0
Article
7 sectionsContents
- Groups
- History
- Evolutionary relationships
- Phylogeny
- Sexual cycle
- References
- External links
The Rhizaria are a diverse and species-rich clade of mostly unicellular eukaryotes. Except for the chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthetic, but many Foraminifera and Radiolaria have a symbiotic relationship with unicellular algae. A multicellular form, Guttulinopsis vulgaris, a cellular slime mold, has been described. This group was used by Cavalier-Smith in 2002, although the term "Rhizaria" had been long used for clades within the currently recognized taxon.
Being described mainly from rDNA sequences, they vary considerably in form, having no clear morphological distinctive characters (synapomorphies), but for the most part they are amoeboids with filose, reticulose, or microtubule-supported pseudopods. In the absence of an apomorphy, the group is ill-defined, and its composition has been very fluid. Some Rhizaria possess mineral exoskeletons (thecae or loricas), which are in different clades within Rhizaria made out of opal (), celestite (), or calcite ().