Common Flat-body vs common sea hare

Agonopterix heracliana compared with Aplysia punctata

Taxonomic Classification

Rank	Common Flat-body	common sea hare
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Mollusca (Mollusks)
Class	Insecta (Insects)	Gastropoda (Gastropoda)
Order	Lepidoptera (Butterflies & Moths)	Aplysiida (Aplysiida)
Family	Depressariidae	Aplysiidae
Genus	Agonopterix	Aplysia
Species	Agonopterix heracliana	Aplysia punctata

Evolutionary Relationship

Common Flat-body and common sea hare share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Common Flat-body

LC — Least Concern

common sea hare

LC — Least Concern

Physical Characteristics

Attribute	Common Flat-body	common sea hare
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Flat-body

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

common sea hare

Habitat

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

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Common Flat-body

<em>Agonopterix heracliana</em> is a moth belonging to the family Depressariidae within the order Lepidoptera. Commonly known as the common flat-body, this species is named for the flattened resting posture characteristic of the genus Agonopterix. The species is classified as Least Concern on the IUCN Red List, with no indication of significant population decline. <em>Agonopterix heracliana</em> is distributed across northwestern Europe, with documented occurrences in Belgium, Denmark, Norway, and Sweden. Larvae of this species are typically associated with plants in the family Apiaceae, particularly hogweed (Heracleum sphondylium) and related umbellifers, upon which they feed while sheltering in rolled or folded leaves. Adults are typically brownish with subtle markings and are active from late summer through winter and early spring, overwintering as adults — an unusual life history trait among moths. The species inhabits hedgerows, woodland margins, and meadows where its host plants are abundant. Biological traits of this species remain poorly documented in the scientific literature.

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 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden