vs Comet Darner

Cocconeis disculus compared with Anax longipes

Key Differences

• is Not Evaluated while Comet Darner is Least Concern.

Taxonomic Classification

Rank		Comet Darner
Kingdom	Chromista (Chromista)	Animalia (Animals)
Phylum	Ochrophyta (Ochrophyta)	Arthropoda (Arthropods)
Class	Bacillariophyceae (Bacillariophyceae)	Insecta (Insects)
Order	Achnanthales (Achnanthales)	Odonata (Odonata)
Family	Cocconeidaceae	Aeshnidae
Genus	Cocconeis	Anax
Species	Cocconeis disculus	Anax longipes

Conservation Status

NE — Not Evaluated

Comet Darner

LC — Least Concern

Physical Characteristics

Attribute		Comet Darner
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.

Comet Darner

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found in United States.

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.

Comet Darner

<em>Anax longipes</em>, the comet darner, is a large dragonfly in the family Aeshnidae, assessed as Least Concern on the IUCN Red List. It is endemic to the United States, where it inhabits lakes, ponds, and slow-moving rivers with clear water and abundant emergent vegetation. The comet darner is one of the largest North American dragonflies and is distinguished by its brilliant coloration, including a green thorax and a red-spotted abdomen in mature males. The species name longipes refers to its notably long legs. Adults are powerful aerial predators, feeding on a variety of flying insects captured in flight. Larvae are aquatic and predatory, developing in the benthic zone of freshwater habitats where they feed on invertebrates and small vertebrates. The comet darner undertakes seasonal dispersal movements and is most commonly observed near its breeding water bodies during the warmer months.