The ultrastructure of Carpediemonas membranifera (Eukaryota) with reference to the “excavate hypothesis”

doi:10.1016/S0932-4739(99)80044-3

European Journal of Protistology

Volume 35, Issue 4, 30 December 1999, Pages 353-370

https://doi.org/10.1016/S0932-4739(99)80044-3 Get rights and content

Summary

The ultrastructure of Carpediemonas membranifera, a small flagellate isolated from marine intertidal sediments, is presented for the first time. This protist has two flagella inserting at the anterior end of a feeding groove. The posterior flagellum bears three vanes. The cell has an anterior nucleus, a single dictyosome and a hydrogenosome-like network. The flagellar apparatus includes a third, barren basal body. The dorsal surface is supported by a fan of microtubules associated with an anterior microtubular root. Two major microtubular roots, left and right, support the groove. A singlet microtubular root runs posteriorly between them. A suite of non-microtubular fibres support the anterior portions of the major roots. The right root splits in two and most of the individual microtubules supporting the groove are positioned between the two portions. As the groove widens and then narrows, the left root splays, then reduces to one microtubule. Much of the outer portion of the right root is also lost and the remainder becomes associated with a composite, striated and dense fibre which supports the right wall of the groove. The left side of the groove becomes bounded by a ‘false left root’ made up of the singlet root and a microtubule from the inner portion of the right root. All of these root remnants terminate in close association at the posterior end of the groove. In having a feeding groove Carpediemonas belongs to a collection of flagellates referred to as the ‘excavate taxa’. The other excavate taxa are the Heterolobosea, diplomonads, retortamonads, core jakobids (Jakoba, Reclinomonas, Histiona), Malawimonas and Trimastix. Carpediemonas is currently not assignable to any of these taxa. A comparison of various morphological characters across the excavate taxa is supplied. Carpediemonas is most similar to Malawimonas, is relatively similar to the core jakobids, but also contains some ‘retortamonad-like’ features, strengthening the hypothesis that at least the bulk of the excavate taxa have a common excavate ancestor. Understanding precise relationships among the excavate taxa will require a detailed analysis and more data from poorly understood taxa.

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The ultrastructure of Carpediemonas membranifera (Eukaryota) with reference to the “excavate hypothesis”

Summary

comb. (Retortamonadida, Protista). Europ. J. Protistol.

FEMS Microbiol. Ecol.

Europ. J. Protistol.

Europ. J. Protistol.,

Europ. J. Protistol.

Europ. J. Protistol.

FEMS Microbiol. Lett.

Adv. Biophys,

Europ. J. Protistol.

Terminology and nomenclature of the cytoskeletal elements associated with the flagellar/ciliary apparatus in protists

Protoplasma

Ultrastructure of the amoeboflagellate Tetramitus rostratus

J. Protozool.

Studies on amebo-flagellates. I. The general morphology and mastigonts of Trimastigamoeba philippinensis Whitmore 1911

J. Protozool.

Étude ultrastructurale du trophozoite et du kyste chez le genre Chilomastix Aléxéieff, 1910 (Zoomastigophorea, Retortamonadida Grassé, 1952)

J. Protozool.

Étude ultrastructurale du genre Enteromonas da Fonseca (Zoomastigophorea) et révision de l’ordre des Diplomonadida Wenyon

J. Protozool.

Contribution à l’étude cytologique et phylétique des diplozoaires (Zoomastigophorea, Diplozoa, Dangeard 1910). V. Nouvelle interprétation de l’organisation cellulaire de Giardia

Protistologica

Ultrastructure du genre Retortamonas Grassi 1879 (Zoomastigophorea, Retortamonadida Wenrich 1931)

Protistologica

Séparation des genres Trimitus (Diplomonadida) et Tricercomitus (Trichomonadida) d’après leur ultrastructure

Protistologica

Flagellar and cytoskeletal systems in amitochondrial flagellates: Archamoeba, Metamonada and Parabasala

Protoplasma

Cell organization in free-living amitochondriate heterotrophic flagellates

Contribution à l’étude cytologique et phylétique des diplozoaires (Zoomastigophorea, Diplozoa, Dangeard 1910). IV. Étude ultrastructurale du genre Octomitus (Prowazek 1904)

Protistologica

Cell diversification in heterotrophic flagellates

Percolozoa and the symbiotic origin of the metakaryote cell

Kingdom protozoa and its 18 phyla

Microbiol. Rev.

Heterotrophic flagellates from coral reef sediments (Great Barrier Reef, Australia)

Arch. Protistenkd.