Asellus

Classification

Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Superorder: Peracarida
Order: Isopoda
Suborder: Asellota
Superfamily: Aselloidea
Family: Asellidae
Genus: Asellus

Pronunciation

How to pronounce Asellus: //əˈsɛləs//

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Summary

Asellus is a genus of freshwater isopod crustaceans belonging to the family Asellidae, with species distributed primarily in Eurasia and a few in North America. They are primarily detritivores and play a significant role in their ecosystems.

Physical Characteristics

Isopod crustaceans with a dorsally flattened body, typically ranging in size; possess two compound eyes and several pairs of thoracic and abdominal segments.

Identification Tips

Look for a flattened body shape and segmented segments; species can vary in coloration from brown to gray.

Habitat

Freshwater habitats including streams, rivers, and lakes, often found in sediment or among aquatic vegetation.

Distribution

Native to Eurasia; in North America, native species are found in NW Alaska, while some have been introduced in Central California.

Diet

Primarily detritivores, feeding on decomposing organic matter, algae, and plant material.

Life Cycle

Reproductive cycle involves direct development; eggs are carried in a brood pouch until they hatch into juvenile forms.

Reproduction

Asellus species reproduce sexually; females carry eggs in a marsupium (brood pouch) until they hatch.

Predators

Preyed upon by fish, amphibians, and larger aquatic invertebrates.

Ecosystem Role

Important role in nutrient cycling by breaking down organic matter and serving as prey for various aquatic species.

Collecting Methods

Hand collection in freshwater habitats
Using nets to catch specimens from aquatic environments
Sediment sampling to find buried individuals

Preservation Methods

Ethanol preservation
Freezing for morphological study
Drying specimens for museum collections

Evolution

The genus Asellus has undergone taxonomic revisions, with many species previously classified in this genus being reassigned to different genera; reflects ongoing evolutionary adaptations to diverse aquatic environments.

Similar Taxa

Misconceptions

Often confused with other freshwater isopods, leading to misidentification; not all isopods are harmful or parasites, as many play essential ecological roles.