Brook Thistle vs common sea hare

Cirsium rivulare compared with Aplysia punctata

Key Differences

• Brook Thistle is Extinct while common sea hare is Least Concern.

Taxonomic Classification

Rank	Brook Thistle	common sea hare
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Mollusca (Mollusks)
Class	Magnoliopsida (Dicots)	Gastropoda (Gastropoda)
Order	Asterales (Daisies & Sunflowers)	Aplysiida (Aplysiida)
Family	Asteraceae (Daisy Family)	Aplysiidae
Genus	Cirsium	Aplysia
Species	Cirsium rivulare	Aplysia punctata

Conservation Status

Brook Thistle

EX — Extinct

common sea hare

LC — Least Concern

Physical Characteristics

Attribute	Brook Thistle	common sea hare
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brook Thistle

Habitat

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

Range

Found across Europe (7 countries).

common sea hare

Habitat

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

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Brook Thistle

The Brook Thistle (Cirsium rivulare) is a species in the genus Cirsium. It is currently classified as Extinct on the IUCN Red List. Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

common sea hare

<em>Aplysia punctata</em>, the common sea hare, is a large opisthobranch sea slug in the family Aplysiidae, order Aplysiida, found in the northeastern Atlantic Ocean and Mediterranean Sea, with confirmed records from Denmark, Norway, Portugal, and Sweden. This species typically inhabits shallow subtidal and intertidal zones with abundant macroalgae, feeding primarily on red and green algae — a diet that influences the color of the defensive purple ink it secretes when threatened. <em>Aplysia punctata</em> is a simultaneous hermaphrodite, capable of acting as both male and female during mating, and often forms mating chains involving multiple individuals. It can reach considerable size among European opisthobranch species, though body dimensions vary considerably with age and feeding conditions. The species is classified as Least Concern by the IUCN, reflecting stable populations across its coastal range. Biological traits for this species remain poorly documented in the scientific literature, including precise average data on lifespan, body length, weight, and detailed seasonal dietary patterns, though its general herbivorous feeding on macroalgae is well established.

Shared Countries

Both species can be found in 2 countries:

🇳🇴 Norway 🇸🇪 Sweden