The evolution of Protozoa

Patterson, David J.

doi:10.1590/s0074-02761988000500072

Cited by 30 publications

(11 citation statements)

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“…Bodo saltans) use their anterior flagellum to generate the feeding current. The taxon Euglenozoa is usually considered to be related to Heterolobosea, based on some ultrastructural features (Patterson, 1988) and some molecular phylogenies (Baldauf et al, 2000;Edgcomb et al, 2001).…”

Section: Potentially Related Organismsmentioning

confidence: 99%

Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota)

Simpson

2003

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

198

250

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Section: Potentially Related Organismsmentioning

confidence: 99%

Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota)

Simpson

2003

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

198

250

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“…Brugerolle & Müller (2000). Patterson (1988) used Metamonadida more narrowly for retortamonads and diplomonads and enteromonads, a grouping later called Eopharyngia (Cavalier-Smith, 1993a) or simply Metamonada (Cavalier-Smith, 1999). Initially, 18S rRNA trees appeared to confirm the deep divergence of diplomonads and Parabasalia by placing them at the root of the eukaryotic tree (Leipe et al, 1993;Cavalier-Smith, 1993a).…”

Section: Changing Views Of the Metamonadamentioning

confidence: 99%

The excavate protozoan phyla Metamonada Grasse emend. (Anaeromonadea, Parabasalia, Carpediemonas, Eopharyngia) and Loukozoa emend. (Jakobea, Malawimonas): their evolutionary affinities and new higher taxa

Cavalier‐Smith

2003

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

101

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It is argued here that the anaerobic protozoan zooflagellate Parabasalia, Carpediemonas and Eopharyngia (diplomonads, enteromonads, retortamonads) constitute a holophyletic group, for which the existing name Trichozoa is adopted as a new subphylum. Ancestrally, Trichozoa probably had hydrogenosomes, stacked Golgi dictyosomes, three anterior centrioles and one posterior centriole: the typical tetrakont pattern. It is also argued that the closest relatives of Trichozoa are Anaeromonada (Trimastix, oxymonads), and the two groups are classified as subphyla of a revised phylum Metamonada. Returning Parabasalia and Anaeromonadea to Metamonada, as in Grassé 's original classification, simplifies classification of the kingdom Protozoa by reducing the number of phyla within infrakingdom Excavata from five to four. Percolozoa (Heterolobosea plus Percolatea classis nov.) and Metamonada are probably both ancestrally quadriciliate with a kinetid of four centrioles attached to the nucleus; the few biciliates among them are probably secondarily derived. Metamonada ancestrally probably had two divergent centriole pairs, whereas, in Percolozoa, all four centrioles are parallel. It is suggested that Discicristata (Percolozoa, Euglenozoa) are holophyletic, ancestrally with two parallel centrioles. In the phylum Loukozoa, Malawimonadea classis nov. is established for Malawimonas (with a new family and order also) and Diphyllatea classis nov., for Diphylleida (Diphylleia, Collodictyon), is transferred back to Apusozoa. A new class, order and family are established for the anaerobic, biciliate, tricentriolar Carpediemonas, transferring it from Loukozoa to Trichozoa because of its triply flanged cilia; like Retortamonas, it may be secondarily biciliate -its unique combination of putative hydrogenosomes and flanged cilia agree with molecular evidence that Carpediemonas is sister to Eopharyngia, diverging before their ancestor lost hydrogenosomes and acquired a cytopharynx. Removal of anaeromonads and Carpediemonas makes Loukozoa more homogeneous, being basically biciliate, aerobic and free-living, in contrast to Metamonada. A new taxon-rich rRNA tree supports holophyly of Discicristata and Trichozoa strongly, holophyly of Metamonada and Excavata and paraphyly of Loukozoa weakly. Mitochondria were probably transformed into hydrogenosomes independently in the ancestors of lyromonad Percolozoa and Metamonada and further reduced in the ancestral eopharyngian. Evidence is briefly discussed that Metamonada and all other excavates share a photosynthetic ancestry with Euglenozoa and are secondarily non-photosynthetic, as predicted by the cabozoan hypothesis for a single secondary symbiogenetic acquisition of green algal plastids by the last common ancestor of Euglenozoa and Cercozoa. Excavata plus core Rhizaria (Cercozoa, Retaria) probably form an ancestrally photophagotrophic clade. The origin from a benthic loukozoan ancestor of the characteristic cellular features of Percolozoa and Euglenozoa through divergent adaptations for feeding on or ...

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“…Elsewhere among the protists, organisms that share nucleocytoplasmic features to the same degree as do the jakobids have mitochondria with similar structure. Mitochondria1 cristal structure therefore is one of the principal diagnostic features used in contemporary protist classifications [ 1 1,26,28,30]. But among the jakobids, all the major mitochondrial structural types are found: flattened cristae in Jakoba, tubular cristae in Histiona and Reclinomonas, discoidal cristae in the undescribed species.…”

Section: Relationships Of the Jakobidsmentioning

confidence: 99%

The Jakobid Flagellates: Structural Features of Jakoba, Reclinomonas and Histiona and Implications for the Early Diversification of Eukaryotes

O’Kelly¹

1993

J Eukaryotic Microbiology

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ABSTRACT. Jakobid flagellates are small, free‐living, bacterivorous heterotrophs, with similar morphology, asexual reproduction, and nucleocytoplasmic ultrastructural features at interphase and during cell division. Jakoba is typified by aloricate trophic cells, each containing a branched mitochondrion with prominent nucleoids and flattened cristae. Reclinomonas and Histiona are characterized by loricate trophic cells, each with an unbranched mitochondrion without prominent nucleoids or otherwise differentiated regions and bearing tubular cristae. An undescribed genus is typified by aloricate cells, each with an unbranched mitochondrion bearing discoidal cristae. I propose, on the basis of cytoskeletal architecture and other structural and developmental features, that jakobids are ancestral mitochondrial protists, sister taxa to the amitochondnal retortamonads and ancestral to diverse lineages of mitochondrial eukaryotes. Application of different classification paradigms produces different family‐level taxonomies for jakobids.

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The evolution of Protozoa

Cited by 30 publications

References 0 publications

Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota)

Cytoskeletal organization, phylogenetic affinities and systematics in the contentious taxon Excavata (Eukaryota)

The excavate protozoan phyla Metamonada Grasse emend. (Anaeromonadea, Parabasalia, Carpediemonas, Eopharyngia) and Loukozoa emend. (Jakobea, Malawimonas): their evolutionary affinities and new higher taxa

The Jakobid Flagellates: Structural Features of Jakoba, Reclinomonas and Histiona and Implications for the Early Diversification of Eukaryotes

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