Clawed enope squid vs common freshwater nerite

Abraliopsis felis compared with Theodoxus fluviatilis

Taxonomic Classification

Rank	Clawed enope squid	common freshwater nerite
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Mollusca (Mollusks)	Mollusca (Mollusks)
Class	Cephalopoda (Cephalopods)	Gastropoda (Gastropoda)
Order	Oegopsida (Oegopsida)	Cycloneritida (Cycloneritida)
Family	Enoploteuthidae	Neritidae
Genus	Abraliopsis	Theodoxus
Species	Abraliopsis felis	Theodoxus fluviatilis

Evolutionary Relationship

Clawed enope squid and common freshwater nerite share a common ancestor at the Phylum level: Mollusca. (Mollusks)

Conservation Status

Clawed enope squid

LC — Least Concern

common freshwater nerite

LC — Least Concern

Physical Characteristics

Attribute	Clawed enope squid	common freshwater nerite
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Clawed enope squid

common freshwater nerite

Habitat

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

Range

Found across Europe (11 countries).

Clawed enope squid

The Clawed Enope Squid, Ancistrocheirus lesueurii, is a medium-sized oceanic squid in the family Ancistrocheiridae found in mesopelagic and bathypelagic zones of the Atlantic, Pacific, and Indian Oceans. It is the sole species in its family, representing a phylogenetically isolated lineage of deep-sea squids. The species is characterized by powerful, hook-bearing tentacles used to capture prey, an adaptation reflected in its common name. The mantle is muscular and elongated, bearing lateral fins, and the arms bear suckers modified into sharp hooks in adults. Ancistrocheirus lesueurii performs diel vertical migrations, ascending toward the surface at night and retreating to deeper waters during daylight hours. It is a voracious predator of fish and other squids, and is in turn preyed upon by sperm whales, large pelagic fishes, and sharks. Bioluminescent photophores are present on the body and arms, likely functioning in counterillumination or signaling. As a mesopelagic species distributed throughout major ocean basins, the Clawed Enope Squid contributes significantly to vertical carbon transport in marine ecosystems, processing organic material from surface waters and redistributing it at depth. Population status is unknown; the species has not been assessed by IUCN. It is occasionally recovered in the stomach contents of top predators and from deep-sea trawl surveys.

common freshwater nerite

<em>Theodoxus fluviatilis</em>, commonly known as the common freshwater nerite, is a small aquatic gastropod mollusc belonging to the family Neritidae. This species is widely distributed across Europe, with documented occurrences in Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Hungary, Latvia, Norway, and Sweden. It typically inhabits freshwater environments, including rivers, streams, and lakes, where it grazes on algae and biofilm on hard substrates such as rocks and submerged wood. The common freshwater nerite is assessed as Least Concern on conservation metrics, reflecting its broad distribution and relatively stable populations across much of its European range. Biological traits of this species remain poorly documented in the scientific literature. <em>Theodoxus fluviatilis</em> plays an ecological role as a grazer in freshwater benthic communities, contributing to the regulation of algal growth on hard surfaces. The species typically favors clean, well-oxygenated waters and can serve as an indicator of water quality in freshwater systems. Its distinctive small, dome-shaped shell with variable patterning makes it recognizable among freshwater invertebrates.