vs

Cocconeis disculus compared with Cocconeis pinnata

Taxonomic Classification

Rank
Kingdom same	Chromista (Chromista)	Chromista (Chromista)
Phylum same	Ochrophyta (Ochrophyta)	Ochrophyta (Ochrophyta)
Class same	Bacillariophyceae (Bacillariophyceae)	Bacillariophyceae (Bacillariophyceae)
Order same	Achnanthales (Achnanthales)	Achnanthales (Achnanthales)
Family same	Cocconeidaceae	Cocconeidaceae
Genus same	Cocconeis	Cocconeis
Species	Cocconeis disculus	Cocconeis pinnata

Evolutionary Relationship

and share a common ancestor at the Genus level: Cocconeis.

Ansehen Genus: Cocconeis

Conservation Status

NE — Not Evaluated

Physical Characteristics

Attribute
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

Native to Europe and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Norway, and Sweden.

Habitat

Native to Europe and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Norway, and Sweden.

Cocconeis disculus is a freshwater and brackish-water diatom in the family Cocconeidaceae, belonging to the class Bacillariophyceae—the diatoms, a group of unicellular photosynthetic algae encased in ornate silica cell walls called frustules. Like all members of the genus Cocconeis, C. disculus is an adnate, epiphytic species, meaning it lives attached to substrates—typically the surfaces of aquatic macrophytes, filamentous algae, and sediment particles—rather than living freely in the water column. The frustule of Cocconeis species is distinctive in its bilateral symmetry and the characteristic difference between its two valves: the rapheless valve (RV) lacks the raphe slit present on the raphe valve (RV), a feature used in species identification. Cocconeis disculus has been documented from freshwater bodies across South America and various parts of the Northern Hemisphere, with distribution reflecting its tolerance of a range of water temperatures and nutrient conditions. Diatoms like C. disculus are foundational components of aquatic food webs, fixing carbon through photosynthesis and providing a nutritious food source for grazing invertebrates, protists, and larval fish. The species also contributes to the biosilica cycle through the production and dissolution of its silica frustule. As a benthic, substrate-attached organism, Cocconeis disculus serves as a sensitive bioindicator of water quality conditions in freshwater monitoring programs. Its conservation status is not formally evaluated.

Cocconeis pinnata is a marine and brackish-water diatom in the family Cocconeidaceae, distinguished within the genus by the pinnate (feather-like) arrangement of its striae and the specific valve morphology of its silica frustule. As an adnate epiphyte, C. pinnata attaches to a wide variety of substrates in coastal and estuarine environments, including seagrass blades, macroalgal surfaces, sandy sediments, and biogenic hard substrates such as shells and coral rubble. The species has been documented from tropical and subtropical marine habitats across the Indo-Pacific and Atlantic, with records from South American coastal waters as well as other warm marine regions. Cocconeis pinnata plays a significant ecological role in seagrass ecosystems, where epiphytic diatom communities including this species form a productive biofilm layer on leaf surfaces that serves as food for grazing invertebrates, sea urchins, and small fish. In areas of excessive nutrient loading, however, proliferation of epiphytic algae including diatoms can shade out the underlying seagrass, contributing to meadow decline. The production and dissolution of silica frustules by marine benthic diatoms contributes to the benthic silica cycle, linking biological productivity with the geochemistry of shallow coastal sediments. Species-level identification of Cocconeis taxa requires electron microscopy due to subtle morphological differences. Conservation status has not been formally assessed.