Arctic barrel-bubble vs coast amaranth

Retusa obtusa compared with Amaranthus pumilus

Key Differences

Arctic barrel-bubble is Least Concern while coast amaranth is Extinct.

Taxonomic Classification

Rank	Arctic barrel-bubble	coast amaranth
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Magnoliophyta (Flowering Plants)
Class	Gastropoda (Gastropoda)	Magnoliopsida (Dicots)
Order	Cephalaspidea (Cephalaspidea)	Caryophyllales (Caryophyllales)
Family	Retusidae	Amaranthaceae
Genus	Retusa	Amaranthus
Species	Retusa obtusa	Amaranthus pumilus

Conservation Status

Arctic barrel-bubble

LC — Least Concern

coast amaranth

EX — Extinct

Physical Characteristics

Attribute	Arctic barrel-bubble	coast amaranth
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Arctic barrel-bubble

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

coast amaranth

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Found in Japan.

Arctic barrel-bubble

The Arctic barrel-bubble (Retusa obtusa) is a species in the genus Retusa. It is currently classified as Least Concern on the IUCN Red List. Typically found in terrestrial and aquatic habitats including forests and freshwater.

coast amaranth

Coast amaranth (Amaranthus pumilus) is an annual herb in the family Amaranthaceae, native to the Atlantic and Gulf coasts of the eastern United States, where it once grew on coastal foredunes, beach strand, and shell-hash substrates above the high tide line from New York south to South Carolina. It is a low-growing, fleshy plant with small, rounded leaves and inconspicuous green flowers typical of the genus. Coast amaranth is assessed as Extinct in the Wild by the IUCN, as it has not been reliably documented from wild populations since the mid-20th century; the last confirmed collections date to the 1960s. The species' decline and likely extinction resulted from intense human pressure on Atlantic coastal habitats through shoreline development, beach stabilisation, vehicular traffic on beaches, and increased storm frequency disrupting pioneer dune vegetation. It is federally listed as Threatened in the United States, though this listing predates confirmed extinction in the wild. A small number of ex-situ accessions may exist in botanical garden collections. Genetic material and seed banking efforts represent the only remaining conservation options for this critically reduced species.