Coscinodiscaceae

Coscinodiscaceae is a family of diatom the order Coscinodiscales. Diatoms are a type of algae characterized by their unique silica cell walls.

Coscinodiscaceae
Coscinodiscus radiatus
Scientific classification
Domain:	Eukaryota
Clade:	Sar
Clade:	Stramenopiles
Phylum:	Ochrophyta
Clade:	Diatomeae
Class:	Bacillariophyceae
Order:	Coscinodiscales
Family:	Coscinodiscaceae Kützing, 1844
Type genus
Coscinodiscus Ehrenberg, 1839
Genera
Brightwellia Coscinodiscus Craspedodiscus Palmeria Palmerina Stellarima

Classification

The family includes several genera, such as Brightwellia, Coscinodiscus, Craspedodiscus, Palmeria, and Stellarima.^[1]

Morphology

Members of the Coscinodiscaceae family typically exhibit disc-shaped, cylindrical, or wedge-shaped cells. Their frustules (silica cell walls) can be quite large, reaching up to 500 µm in diameter. The valve face is flat or lens-shaped, with radiate areolae extending from a central annulus.

Distribution

Species within the Coscinodiscaceae family are widely distributed across various aquatic environments, ranging from oceans to freshwater bodies. They are found in regions from warm waters to boreal zones.^[2]

Ecological role

Diatoms, including those in the Coscinodiscaceae family, play a crucial role in aquatic ecosystems. As primary producers, they generate organic matter through photosynthesis, which supports the food web.^[2]

Key characteristics of each genus

Coscinodiscus

• Shape: Typically, disc-shaped or slightly eccentric in girdle view.
• Frustules: Large, up to 500 µm in diameter.
• Valve face: Flat or lens-shaped with radiate areolae extending from a central annulus.
• Areolae: Loculate, covered externally by porose vela and open internally via foramina.
• Rimoportulae: Present, arranged at regular intervals around the valve face .

Brightwellia

^[1]

• Shape: Cylindrical or wedge-shaped.
• Frustules: Smaller compared to Coscinodiscus.
• Valve face: Often more convex with radiate areolae.
• Areolae: Similar loculate structure but with different external coverings.
• Rimoportulae: Less prominent, often fewer in number

Craspedodiscus

^[1]

• Shape: Disc-shaped but with more pronounced eccentricity.
• Frustules: Medium-sized.
• Valve face: Flat with radiate areolae, similar to Coscinodiscus but with distinct patterns
• Areolae: Loculate, with unique internal structures
• Rimoportulae: Present, often larger and more spaced out

Palmeria

^[1]

• Shape: Cylindrical or barrel shaped.
• Frustules: Medium to large.
• Valve face: Convex with radiate areolae.
• Areolae: Loculate, with complex internal structures.
• Rimoportulae: Prominent, often with elaborate internal processes

Stellarima

^[1]

• Shape: Star-shaped or disc-shaped with pronounced radial symmetry.
• Frustules: Medium-sized.
• Valve face: Flat with radiate areolae extending from a central point.
• Areolae: Loculate, with unique external coverings.
• Rimoportulae: Present, often arranged in a star-like pattern

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