Brook Floater vs Cinerous Groundling

Alasmidonta varicosa compared with Bryotropha terrella

Key Differences

• Brook Floater is Vulnerable while Cinerous Groundling is Least Concern.

Taxonomic Classification

Rank	Brook Floater	Cinerous Groundling
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Arthropoda (Arthropods)
Class	Bivalvia (Bivalvia)	Insecta (Insects)
Order	Unionida (Unionida)	Lepidoptera (Butterflies & Moths)
Family	Unionidae	Gelechiidae
Genus	Alasmidonta	Bryotropha
Species	Alasmidonta varicosa	Bryotropha terrella

Evolutionary Relationship

Brook Floater and Cinerous Groundling share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Brook Floater

VU — Vulnerable

Cinerous Groundling

LC — Least Concern

Physical Characteristics

Attribute	Brook Floater	Cinerous Groundling
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.

Cinerous Groundling

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, 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.

Cinerous Groundling

The cinerous groundling (Bryotropha terrella) is a small moth in the family Gelechiidae, distributed across Europe including Britain, Scandinavia, and much of continental Europe. It inhabits dry, open habitats such as heathland, sand dunes, chalk grassland, and dry grassland margins, where its larvae feed on mosses and low-growing plants close to the soil. The adult moth has pale straw-colored to gray-brown forewings with indistinct markings, providing camouflage in its dry, open habitat. Like many gelechiid moths, Bryotropha terrella is a small, inconspicuous species that is frequently under-recorded due to the challenges of identifying micro-moths. The species is classified as Least Concern, with populations found across a wide range of European countries with suitable dry, open habitat. Its larval association with mosses and low vegetation makes it dependent on short, open sward conditions—habitats that have declined in parts of Europe due to agricultural intensification, scrub encroachment following the abandonment of traditional grazing, and afforestation. Moth surveys using light traps and careful examination of micro-lepidoptera have expanded knowledge of this and related gelechiid species' distributions. Conservation of dry heathland and chalk grassland habitats benefits a wide range of invertebrates including this species.