| Arthracanthida | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Clade: | Sar |
| Clade: | Rhizaria |
| Phylum: | Radiozoa |
| Class: | Acantharia |
| Order: | Arthracanthida Schewiakoff, 1926[1] |
| Synonyms | |
Acanthometrida | |
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Arthracanthida, a subclass ofAcantharea, is a group of marineprotozoans. They consist mainly of a gelatinous sheath filled withcytoplasm and a skeleton of up to 20 radially placedspicules made ofcelestine (strontium sulfate). While mostly found in the upper areas of the ocean, they are able to move vertically by usingmicrofilaments attached to the spicules to expand and contract the sheath. They are plentiful in theGulf Stream during the summer months, but little is known about their overall distribution.