Brook Floater vs St. James' shell

Alasmidonta varicosa compared with Pecten maximus

Key Differences

• Brook Floater is Vulnerable while St. James' shell is Least Concern.

Taxonomic Classification

Rank	Brook Floater	St. James' shell
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Mollusca (Mollusks)	Mollusca (Mollusks)
Class same	Bivalvia (Bivalvia)	Bivalvia (Bivalvia)
Order	Unionida (Unionida)	Pectinida (Pectinida)
Family	Unionidae	Pectinidae
Genus	Alasmidonta	Pecten
Species	Alasmidonta varicosa	Pecten maximus

Evolutionary Relationship

Brook Floater and St. James' shell share a common ancestor at the Class level: Bivalvia. (Bivalvia)

Conservation Status

Brook Floater

VU — Vulnerable

St. James' shell

LC — Least Concern

Physical Characteristics

Attribute	Brook Floater	St. James' shell
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.

St. James' shell

Habitat

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

Range

Widely distributed across Asia (China), Europe (8 countries), and South America (Chile).

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.

St. James' shell

St. James' shell (Pecten maximus) is classified as Least Concern (LC) on the IUCN Red List. Widespread and abundant across its range, with stable populations and no immediate conservation concerns.