Cyprogenia stegaria
CR

Cyprogenia stegaria

Unknown

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Fanshell

Overview

A detailed profile for this species is sourced from the IUCN Red List of Threatened Species as assessments become available.

Cyprogenia stegaria faces severe population declines primarily due to habitat degradation from dam construction and river channelization, which have altered natural flow regimes essential for reproduction. Water quality deterioration from agricultural runoff and urban pollution has further compromised the species' survival, while invasive zebra mussels compete for resources and attach to native shells. The species' dependence on specific fish hosts for larval development makes it particularly vulnerable to declining fish populations in degraded river systems.

Threat summary

Habitat

Cyprogenia stegaria inhabits medium to large rivers with stable gravel and sand substrates, typically in areas with moderate to swift currents. The species requires clean, well-oxygenated water and depends on specific fish species as hosts for its larval stage.

FRESHWATER· major

Other threatened species in UNIONIDAE

VU

Brazzaea anceyi

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Lampsilis higginsiiEN

Lampsilis higginsii

Unknown
CR

Recovery Pearly Mussel

Elliptio nigella

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EN

Triangle Pigtoe

Fusconaia lananensis

Declining

Frequently asked questions

Why is Cyprogenia stegaria classified as Critically Endangered?
Cyprogenia stegaria is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Cyprogenia stegaria faces severe population declines primarily due to habitat degradation from dam construction and river channelization, which have altered natural flow regimes essential for reproduction. Water quality deterioration from agricultural runoff and urban pollution has further compromised the species' survival, while invasive zebra mussels compete for resources and attach to native shells. The species' dependence on specific fish hosts for larval development makes it particularly vulnerable to declining fish populations in degraded river systems.
Where does Cyprogenia stegaria live?
Cyprogenia stegaria occurs in across multiple regions. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Cyprogenia stegaria?
The main threats to Cyprogenia stegaria are ai-1, ai-2, ai-3, and ai-4. The full IUCN-classified threat record for this species is detailed on the species page.

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