Brook Floater vs

Alasmidonta varicosa compared with Chrysococcus cystophorus

Key Differences

Brook Floater is Vulnerable while is Not Evaluated.

Taxonomic Classification

Rank	Brook Floater
Kingdom	Animalia (Animals)	Chromista (Chromista)
Phylum	Mollusca (Mollusks)	Ochrophyta (Ochrophyta)
Class	Bivalvia (Bivalvia)	Chrysophyceae (Chrysophyceae)
Order	Unionida (Unionida)	Chromulinales (Chromulinales)
Family	Unionidae	Dinobryaceae
Genus	Alasmidonta	Chrysococcus
Species	Alasmidonta varicosa	Chrysococcus cystophorus

Conservation Status

Brook Floater

VU — Vulnerable

NE — Not Evaluated

Physical Characteristics

Attribute	Brook Floater
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brook Floater

Habitat

Native to North America, inhabiting ecosystems characteristic of the region.

Range

Found in United States. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Brook Floater

The Brook Floater (Alasmidonta varicosa) is a species in the genus Alasmidonta. It is currently classified as Vulnerable on the IUCN Red List. Native to North America, inhabiting ecosystems characteristic of the region.

Chrysococcus cystophorus is a unicellular freshwater chrysophyte microalga in the genus Chrysococcus, family Chromulinaceae, class Chrysophyceae. The specific epithet cystophorus, meaning cyst-bearing, references this species' relationship with siliceous cyst formation — a shared feature across many chrysophytes that produce species-specific resting stages called stomatocysts or statospores. In chrysophytes, the stomatocyst is a silicified internal cyst with a characteristic plug-sealed pore, and its morphology is often used as an additional taxonomic character in species identification. C. cystophorus inhabits freshwater environments and has been recorded from Norwegian waters along with other Scandinavian localities, fitting the pattern of chrysophyte species diversity documented through freshwater surveys in the region. Chrysococcus cells are enclosed within a lorica — a proteinaceous or organic outer vessel — from which flagella emerge for locomotion. The lorica shape and ornamentation, along with the dimensions and flagellar arrangement, are primary characters used for species identification. Like other chrysophytes, C. cystophorus is golden-brown in color owing to chlorophylls a and c together with fucoxanthin pigments in the chloroplast. Chrysococcus species function as primary producers in freshwater plankton communities, particularly in oligotrophic lakes where smaller algae outcompete larger taxa. C. cystophorus has not been evaluated under IUCN Red List criteria and is listed as Not Evaluated, consistent with the general status of freshwater microalgal taxa.