Microworld

world of amoeboid organisms

Menu
Menu

Order Arcellinida Kent 1880

Diagnosis: Cell covered with hard or highly rigid organic or mineral extracellular test consisting of either self-secreted elements (calcareous, siliceous or chitinoid), a sheet-like chitinoid structure, or recycled organic or mineral particles bound together, with a single main aperture.

Remarks: Arcellinida comprises all testate amoebae with lobose pseudopodia. It is the largest group of testate amoebae with 687 nominal species (Kosakyan et al, 2016). However, the major part of these species needs comprehensive nomenclature and taxonomic revision.
Arcellinida exhibit a wide array of the test shapes composed of different material, which was the key characteristic for their classification. Meisterfeld (2000) organized them into three suborders: Arcellina, Difflugina and Phryganellina.
Recent molecular investigations has challenged the system, and the positions of many species and genera were switched between families. These molecular reconstructions have demonstrated the limitations of the use of test composition as a classification character. A number of modifications were made on high as well as low-taxonomic levels. Higher-level taxonomy of Arcellinida is uncertain, while lower-level taxonomy is constantly changing (Kosakyan et al, 2016; Gomaa et al., 2017).

Further reading:

Kosakyan et al. (2016): Current and future perspectives on the systematics, taxonomy and nomenclature of testate amoebae – European Journal of Protistology

Gomaa et al. (2017): A contribution to the phylogeny of agglutinating Arcellinida (Amoebozoa) based on SSU rRNA gene sequences – European Journal of Protistology 59: 99-107

González-Miguéns, R., Todorov, M., Blandenier, Q., Duckert, C., Porfirio-Sousa, A.L., Ribeiro, G.M., Ramos, D., Lahr, D.J.G., Buckley, D., Lara, E. (2022):  Deconstructing Difflugia: the tangled evolution of lobose testate amoebae shells (Amoebozoa: Arcellinida) illustrates the importance of convergent evolution in protist phylogeny, Molecular Phylogenetics and Evolution, doi: https://doi.org/10.1016/j.ympev. 2022.107557

Recent posts

Haplomyxa spec.

Main cell body Haplomyxa spec. Description: The cell had a cylindrical flattened body from which numerous granuloreticulopodia emerged. The common shape was more or less

Read More »

Valkanovia delicatula

V. delicatula, after Valkanov, 1962 Genus Valkanovia  Tappan, 1966 Diagnosis: Shell ovoid, oblate, elliptical in cross-section, composed of elongated elliptical hyaline scales arranged in a

Read More »

Gocevia pontica

Gocevia pontica, after Valkanov, 1934 Gocevia pontica Valkanov, 1934 Diagnosis: Clearly addressed bipolarity. Body covered by a weakly flexible tectum covered with foreign bodies. The

Read More »

Nabranella

N. brevis, after Snegovaya and Alekperov, 2009 Genus Nabranella Snegovaya and Alekperov, 2009 Diagnosis: Shell oval or spherical shape without neck. Apical top flat and

Read More »

Armipyxis

Genus Armipyxis Dekhtiar, 2009 Genus Armipyxis was created by Dekhtiar (2009) to accommodate all species with internal struts. However, C. aculeata may also have struts, although

Read More »

Netzelia pseudolimnetica

N. pseudolimnetica, after Penard, 1902 Netzelia pseudolimnetica Ogden and Meisterfeld, 1989 Synonym Difflugia limnetica (Levander, 1900) Penard, 1902. D. limnetica – Pejler, 1962, Oikos, 12,

Read More »

Cylindrifflugia hiraethogii

C. hiraethogii, after Ogden. 1983 Cylindrifflugia hiraethogii (Ogden, 1983) González-Miguéns et al., 2022 Diagnosis: the shell is light yellow or transparent, thin pyriform with a distinct

Read More »

Cylindrifflugia bacillariarum

  C. bacillariarum, 103 – 114 µm – Fochteloërveen, Netherlands   Cylindrifflugia bacillariarum (Perty, 1849) n. comb. González-Miguéns et al., 2022 Diagnosis: shell transparent, colorless or

Read More »

Cylindrifflugia elegans

C. elegans, length 84-102 µm, Gaasterland Cylindrifflugia elegans (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia elegans Penard, 1890 Diagnosis: shell outline rough, pyriform

Read More »

Cylindrifflugia lanceolata

C. lanceolata, shells 153-169 µm long, nuclei 23-26 µm (Naardermeer, Netherlands) Cylindrifflugia lanceolata (Penard, 1890) n. comb. González-Miguéns et al., 2022 Basionym: Difflugia lanceolata Penard,

Read More »