A sea mat (Schizoporella unicornis)
|Researched by||Chloe Wilson||Refereed by||Admin|
|Authority||(Johnston in Wood, 1844)|
|Other common names||-||Synonyms||-|
Schizoporella unicornis forms sheets with one or more layers of zooids on various substrata on the lower shore. The whitish or pink colonies coat hard surfaces such as stones and shells or the holdfasts of large algae (e.g. Himanthalia and Laminaria). The zooids are arranged in a regular pattern. Individual zooids are convex, usually rectangular in shape, and typically 0.4 - 0.7 mm x 0.3 - 0.5 mm in size. Deep grooves mark the boundaries between the zooids. Each zooid has a D-shaped orifice with a V-shaped indentation in the middle of the straight edge. A single or pair of raised avicularia sit either side of the orifice. Later in development, a conical umbo (small projection) appears directly below the V-shaped sinus of each primary orifice.
Recorded distribution in Britain and IrelandCommon on all British and Irish coasts, although under reported on some coasts (particularly around Ireland).
Schizoporella unicornis is scattered circumglobally, mainly in temperate coastal regions. Most records are located in the northern hemisphere, with colonies commonly occurring on the West and East coasts of the USA, the British Isles and the Northeastern Mediterranean. However, it has also been recorded in the tropics (e.g. Hawaii and Port Sudan). In the southern hemisphere, Schizoporella unicornis has been found at a single location near Curitiba, Brazil.
HabitatColonizes a variety of substrata from the lower shore to the shallow sublittoral. These include the underside of rocks and shells, Himanthalia buttons and Laminaria holdfasts.
Depth rangeLower Shore - Shallow Sublittoral
- Polygonous (typically rectangular) zooids, approximately 0.4 - 0.7 mm x 0.3 - 0.5 mm.
- Colonies form uni or multilaminar sheets.
- Primary orifices are D-shaped and wider than long.
- Polypide has 21-24 tentacles.
- Ovicell is globular and lacks pores (imperforate).
- Avicularia with acute triangular rostra are present either singularly or in pairs on each zooid.
- External surface of zooids is densely perforated by round pores.
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Last Updated: 10/10/2017