Overview
Taxonomy
The Infrakingdom Rhizaria is further organized into finer groupings including:
- Superphylum (2): Aschelminthes · Eutrochozoa
- Phylum (4): Cercozoa · Foraminifera · Mollusca · Radiozoa
Phyla
Cercozoa
Foraminifera
The Foraminifera ("hole bearers"), or forams for short, are a large phylum of amoeboid protists. They are among the most common marine plankton species. Forams have reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in structure. These shells are made of calcium carbonate (CaCO3) or agglutinated sediment particles. About 275,000 species are recognized, both living and fossil. They are usually less than 1 mm in size, but some are much larger, the largest species reaching up to 20 cm. [more]
Mollusca
The Mollusca (pronounced ), common name molluscs or mollusks (pronounced /'m?l?sks/), is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. Molluscs are highly diverse, not only in size and in anatomical structure, but also in behaviour and in habitat. The phylum is typically divided into nine or ten taxonomic classes, of which two are entirely extinct. Cephalopod molluscs such as squid, cuttlefish and octopus are among the most neurologically advanced of all invertebrates ? and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropods (snails and slugs) are by far the most numerous molluscs in terms of classified species, and account for 80% of the total. [more]
Radiozoa
Radiolarians (also radiolaria) are amoeboid protozoa (diameter 0.1-0.2 mm) that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. They are found as zooplankton throughout the ocean, and their skeletal remains cover large portions of the ocean bottom as radiolarian ooze. Due to their rapid turn-over of species, they represent an important diagnostic fossil found from the Cambrian onwards. Some common radiolarian fossils include , Heliosphaera and Hexadoridium. [more]
At least 709 species and subspecies belong to the Phylum Radiozoa.
More info about the Phylum Radiozoa may be found here.
Sources
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