Phaeodarea

The Phaeodarea are a group of heterotrophic protists that systematically long as radiolarians ( radiolarians ) was considered to be today but asked to Cercozoa.

Features

The Phaeodarea are single-celled organisms with an internal skeleton. Its central capsule has a thickened, double-layered capsule wall with two types of openings: a large, referred to as Astropylum opening with a large amount of continuous cytoplasm, and smaller openings Parapylae that usually sit at the side and pull it through the thin Cytoplasmastränge. Inside the cell there is a dense mass of dark pigmented, granular cytoplasm, the Phaeodium containing undigested waste.

When present, there is a mineral skeleton of scattered arranged spines or hollow silicate rods which are connected by organic material. They have a large variety of shapes.

System

The Phaeodarea were asked because of their morphology since its first description by Ernst Haeckel in 1879 to the Radiolaria. Molecular genetic studies showed, however, that they are not closely related to the other two groups of Radiolaria, but belong to the Cercozoa.

They form a monophyletic group. In several works, they were the sister group of the genus Pseudodifflugia, their common position within the Cercozoa is unclear.

After Adl et al. include the Phaeodarea following groups:

• Phaeoconchia
• Phaeocystina
• Phaeogromia
• Phaeosphaeria

Documents

• Sina M. Adl et al.: The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists. The Journal of Eukaryotic Microbiology, Volume 52, 2005, pp. 399-451 (Abstract and full text)