ENEndangered

liten elvebreddsedderkopp

Arctosa stigmosa

Arctosa stigmosa is a medium-sized wolf spider with distinctive dark markings on its carapace and a mottled brown-gray coloration that provides excellent camouflage against riverbank substrates. This semi-aquatic arachnid plays a crucial role as both predator and prey in riparian ecosystems, hunting small invertebrates along water margins while serving as food for birds and larger arthropods.

14

Countries

01Classification

Taxonomy & Classification

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Lycosidae

Genus

Arctosa

liten elvebreddsedderkopp belongs to the family Lycosidae, order Araneae, within the Arachnida class.

02Description

Species Profile

Arctosa stigmosa is a medium-sized wolf spider with distinctive dark markings on its carapace and a mottled brown-gray coloration that provides excellent camouflage against riverbank substrates. This semi-aquatic arachnid plays a crucial role as both predator and prey in riparian ecosystems, hunting small invertebrates along water margins while serving as food for birds and larger arthropods.

Arctosa stigmosa is declining primarily due to habitat degradation and loss of suitable riverbank environments. Human activities including river regulation, pollution, and development along waterways have significantly reduced the quality and extent of the specialized sandy and gravelly riverbank habitats this species requires.

Key Facts

IUCN StatusEndangered (EN)
GroupArachnids
03Habitat

Habitat & Distribution

This species inhabits the sandy and gravelly shores of fast-flowing rivers and streams, particularly areas subject to natural flooding cycles that create the dynamic sediment conditions it requires. It constructs burrows in loose substrate within the splash zone and areas of seasonal inundation along pristine waterways.

04Threats

Threats

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IUCN Red List: Endangered

Arctosa stigmosa is declining primarily due to habitat degradation and loss of suitable riverbank environments. Human activities including river regulation, pollution, and development along waterways have significantly reduced the quality and extent of the specialized sandy and gravelly riverbank habitats this species requires.

Habitat degradation from human development

HighOngoing

River regulation and flow modification

HighOngoing

Climate change affecting water levels

MediumOngoing

Loss of natural riverbank vegetation

MediumOngoing

Water pollution and contamination

MediumOngoing
Community

Community Sightings

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07Sources

Sources & Attribution

How to Cite

IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS

GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org

This page: SpeciesRadar (2025). liten elvebreddsedderkopp (Arctosa stigmosa). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/liten-elvebreddsedderkopp

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