CR

Southern Acorn Riffle Shell

Epioblasma othcaloogensis

Declining

Overview

Epioblasma othcaloogensis, the southern acornshell or southern acorn riffle shell, was a species of freshwater mussel in the family Unionidae. It was only known from the Coosa and Cahaba Rivers of the southeastern United States.

The Southern Acornshell faces severe threats from dam construction and river channelization that have fragmented and degraded its riverine habitat throughout the Tennessee River system. Water quality degradation from agricultural runoff, urban development, and industrial pollution has further compromised the species' survival. The mussel's dependence on specific fish hosts for reproduction makes it particularly vulnerable to declining fish populations caused by habitat modification and pollution.

Threat summary

Habitat

The Southern Acornshell inhabits clean, flowing waters of medium to large rivers with stable gravel and sand substrates. It requires well-oxygenated water and is typically found in areas with moderate current flow in the Tennessee River drainage system.

Wetlands (inland) - Permanent rivers/streams· major

Conservation measures underway

Resource & habitat protectionHabitat & natural process restorationSpecies managementSpecies recoveryLinked enterprises & livelihood alternatives

Other threatened species in UNIONIDAE

VU

Brazzaea anceyi

Unknown
Lampsilis higginsiiEN

Lampsilis higginsii

Unknown
EN

Triangle Pigtoe

Fusconaia lananensis

Declining
VU

Lampsilis dolabraeformis

Unknown

Threatened in United States

VU

Lepiota echinella

Unknown
VU

Paddlefish

Polyodon spathula

Unknown
VU

Copper Shark

Carcharhinus brachyurus

Declining
EN

Lyophyllum deliberatum

Unknown

Frequently asked questions

Why is Southern Acorn Riffle Shell classified as Critically Endangered?
Southern Acorn Riffle Shell 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. The Southern Acornshell faces severe threats from dam construction and river channelization that have fragmented and degraded its riverine habitat throughout the Tennessee River system. Water quality degradation from agricultural runoff, urban development, and industrial pollution has further compromised the species' survival. The mussel's dependence on specific fish hosts for reproduction makes it particularly vulnerable to declining fish populations caused by habitat modification and pollution.
Where does Southern Acorn Riffle Shell live?
Southern Acorn Riffle Shell occurs in United States. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Southern Acorn Riffle Shell?
The main threats to Southern Acorn Riffle Shell are 1.1, 11.4, 2.1, and 3.2. The full IUCN-classified threat record for this species is detailed on the species page.

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