vs Commerson s Dolphin

Cocconeis disculus compared with Cephalorhynchus commersonii

Key Differences

• is Not Evaluated while Commerson s Dolphin is Least Concern.

Taxonomic Classification

Rank		Commerson s Dolphin
Kingdom	Chromista (Chromista)	Animalia (Animals)
Phylum	Ochrophyta (Ochrophyta)	Chordata (Chordates)
Class	Bacillariophyceae (Bacillariophyceae)	Mammalia (Mammals)
Order	Achnanthales (Achnanthales)	Cetacea (Whales & Dolphins)
Family	Cocconeidaceae	Delphinidae (Oceanic Dolphins)
Genus	Cocconeis	Cephalorhynchus
Species	Cocconeis disculus	Cephalorhynchus commersonii

Conservation Status

NE — Not Evaluated

Commerson s Dolphin

LC — Least Concern

Physical Characteristics

Attribute		Commerson s Dolphin
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.

Commerson s Dolphin

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

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.

Commerson s Dolphin

<em>Cephalorhynchus commersonii</em>, commonly known as Commerson's Dolphin, is a small cetacean in the family Delphinidae. This species is classified as Least Concern on the IUCN Red List and is notable for its striking black-and-white coloration, which makes it one of the most visually distinctive dolphin species. Commerson's Dolphins typically inhabit coastal and nearshore marine environments of the Southern Hemisphere, particularly around the Falkland Islands, the southern tip of South America, and a geographically isolated population near the Kerguelen Islands in the Indian Ocean. These dolphins are highly social animals, often observed in small groups engaging in acrobatic behaviors near the surface. They typically feed on fish, squid, and crustaceans, often hunting cooperatively in shallow waters and kelp beds. Their average lifespan is approximately 18 years, and they are known for their fast, energetic swimming. Commerson's Dolphins are sometimes caught as bycatch in fishing nets, posing a localized conservation concern despite their overall Least Concern status.