Misplaced Pages

Desmothoracid
Blaschka glass model of Clathrulina elegans
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Phylum:	Cercozoa
Class:	Granofilosea
Order:	Desmothoracida Hertwig & Lesser, 1874 emend. Honigberg et al. 1964
Family:	Clathrulinidae Claus, 1874
Genera
See text
Synonyms
Cryptaxohelida Desmothoraca Hertwig & Lesser 1874 Clathrulinida Starobogatov 1980

Order Desmothoracida, the desmothoracids, are a group of heliozoan protists, usually sessile and found in freshwater environments. The adult is a spherical cell around 10-20 μm in diameter surrounded by a perforated organic lorica, or shell, with many radial pseudopods projecting through the holes to capture food. These are supported by small bundles of microtubules that arise near a point on the nuclear membrane. Unlike other heliozoans, the microtubules are not in any regular geometric array, there does not appear to be a microtubule organizing center, and there is no distinction between the outer and inner cytoplasm.

Reproduction takes place by the budding-off of small motile cells, usually with two flagella. Later these are lost, and the pseudopods and lorica are formed. Typically, a single lengthened pseudopod will secrete a hollow stalk that attaches the cell to the substrate. The form of the flagella, the tubular cristae within the mitochondria, and other characters have led to the suggestion that the desmothoracids belong among what is now the Cercozoa. This was later confirmed by genetic studies.

As of the year 2000, the order Desmothoracida contained five genera with a total of 10 species.

• Order Desmothoracida Hartwig & Lesser 1874 emend. Honigberg et al. 1964
  • Family Clathrulinidae Claus 1874
    • Genus Clathrulina Cienkowski 1867
      • Species Clathrulina elegans Cienkowski 1867
      • Species Clathrulina smaragdea (Entz 1877) Mikrjukov 2000
    • Genus Hedriocystis Hertwig & Lesser 1874
      • Species Hedriocystis pellucida Hertwig & Lesser 1874
      • Species Hedriocystis minor Siemensma 1991
      • Species Hedriocystis zhadani Mikrjukov 2000
    • Genus Penardiophrys Mikrjukov 2000
      • Species Penardiophrys reticulata (Penard 1904) Mikrjukov 2000
      • Species Penardiophrys spinifera (Brown 1918) Mikrjukov 2000
    • Genus Cienkowskya Schaudinn 1896 non Regel & Rach 1859 non Solms 1867
      • Species Cienkowskya mereschkovckii (Cienkowsky 1881) Schaudinn 1896
      • Species Cienkowskya brachypous (De Saedeleer 1930) Mikrjukov 2000
    • Genus Actinosphaeridium Zacharias 1893
      • Species Actinosphaeridium pedatus Zacharias 1893

Notes

1. Mikrjukov, K. A. (2000). Taxonomy and phylogeny of Heliozoa. 1. The order Desmothoracida Hertwig et Lesser, 1874. Acta Protozoologica 39(2) 81-97.
2. "Part 1- Virae, Prokarya, Protists, Fungi". Collection of genus-group names in a systematic arrangement. Archived from the original on 14 August 2016. Retrieved 30 June 2016.

References

• Nikolaev, S.I.; et al. (2003). "Genetic relationships between desmothoracid Heliozoa and gymnophryid amoebas as evidenced by comparison of 18S rRNA genes". Doklady Biological Sciences. 393 (1–6): 553–6. doi:10.1023/B:DOBS.0000010322.33294.9f. PMID 14994549. S2CID 21189865.

• Filosa
• Amoeboids