FWS Focus

Overview

Characteristics
Overview

The Coosa moccasinshell, Medionidus parvulus, is a small species of mussel that historically occurred in the Cahaba River, the Sipsey Fork of the Black Warrior River and the Coosa River, as well as tributaries in Alabama, Georgia and Tennessee. However, due to habitat loss and degradation, the species has disappeared from the mainstems of all of these rivers and persists in mostly small, localized populations throughout their tributaries.

Scientific Name

Medionidus parvulus
Common Name
Coosa moccasinshell
FWS Category
Clams
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Similar Species

Characteristics
Similar Species

It is difficult to distinguish between the Alabama moccasinshell and Coosa moccasinshell, however, the posterior end of the Alabama moccasinshell is typically more pointed than that of the Coosa moccasinshell.

Characteristic category

Life Cycle

Characteristics
Life Cycle

Freshwater mussels live an interesting multi-stage life cycle which depends upon a fish host to complete. Males release sperm into the water column, to be hopefully siphoned in by the incurrent aperture of the females, where the eggs held within her gills are then fertilized. Once the fertilized eggs start to develop, the female becomes inflated or gravid. The fertilized eggs develop into glochidia, which is the mussels larval stage. This stage requires a fish host for transformation into the juvenile stage, which sometimes requires a little coaxing by females. Glochidia are housed in packets called conglutinates and often mimic a food source of the fishes within that ecosystem to lure the fish to bite. Once the fish bites, the glochidia clamp down onto the fish, becoming encysted, and feed from the fish for several weeks until dropping off as juveniles.

Reproduction

The Coosa moccasinshell is believed to be a long term brooder, gravid from October to June. 

Characteristic category

Habitat

Characteristics
Habitat

The Coosa moccasinshell typically occupies sand, gravel or cobble shoals with moderate to strong currents in streams and small rivers.

River or Stream

A natural body of running water.

Characteristic category

Food

Characteristics
Food

Although the diets of freshwater mussels are poorly understood, it is believed to consist of algae and or bacteria. Some studies suggest that the diets of freshwater mussels may change throughout their life, with juveniles collecting organic materials from the substrate though pedal feeding and then developing the ability to filter feed during adulthood. Pedal feeding is a form of deposit feeding where the animal uses their muscular foot to bury into the sediment, collecting organic matter. Filter feeding is a process by which mussels feed off of suspended organic material by pumping in water through their incurrent aperture and out through their excurrent apertures. In doing so they catch small suspended particles as food.

Characteristic category

Behavior

Characteristics
Behavior

Many freshwater mussels spend the majority of their life sedentary and filter feeding on the bottom of rivers and streams. Sometimes they will bury into the sediment, only revealing a small portion of their aperture, which is used for gas exchange and filter feeding. The Coosa moccasinshell is believed to behave similarly to the Alabama moccasinshell, spending most of the time buried in the sediment, emerging only to display the female's modified mantle lure.

Geography

Characteristics
Range

The Coosa moccasinshell has been historically reported from the Cahaba River, the Sipsey Fork of the Black Warrior River and the Coosa River, as well as their tributaries in Alabama, Georgia and Tennessee. Since this species was listed, its presence has been confirmed only in the Conasauga River, in Murray/Whitfield County, Georgia and Bradley County, Tennessee. Additionally at the time of listing, the species was also found in the tributary, Holly Creek, in Murray County, Georgia. Distribution is believed to be less than eight river miles in the Conasauga River and Holly Creek combined.

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Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

8 Items

Listing

Listing

Recovery Plan

Critical Habitat

Critical Habitat

Five Year Review

Five Year Review

Recovery Plan

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Listing

Nov 19, 1991

Nov 19, 1991 Listing (Endangered)
ETWP; Proposed Endangered Status for Eight Freshwater Mussels and Proposed Threatened Status for Thr…
  • Publication type: Proposed
Item 1

Listing

Mar 17, 1993

Mar 17, 1993 Listing (Endangered)
Endangered Status for Eight Freshwater Mussels and Threatened Status for Three Freshwater Mussels in…
  • Publication type: Final
Item 2

Recovery Plan

Jun 29, 1998

Jun 29, 1998 Recovery Plan (Document Availability (non-FR))
Notice a Availability of a Revised Draft Recovery Plan for the Mobile River Basin Aquatic Ecosystem…
  • Publication type: Draft
Item 3

Critical Habitat

Mar 26, 2003

Mar 26, 2003 Critical Habitat
Endangered and Threatened Wildlife and Plants; Proposed Designation of Critical Habitat for Three Th…
  • Publication type: Proposed
Item 4

Critical Habitat

Jul 1, 2004

Jul 1, 2004 Critical Habitat
Designation of Critical Habitat for Three Threatened Mussels and Eight Endangered Mussels in the Mob…
  • Publication type: Final
Item 5

Five Year Review

Jun 14, 2005

Jun 14, 2005 Five Year Review (Information Solicitation)
Initiation of 5-Year Reviews of 25 Southeastern Species
  • Publication type: Notice
Item 6

Five Year Review

Sep 23, 2014

Sep 23, 2014 Five Year Review (Information Solicitation)
5-Year Status Reviews of 27 Southeastern Species; Notice of initiation of reviews; request for infor…
  • Publication type: Notice
Item 7

Recovery Plan

Jun 27, 2019

Jun 27, 2019 Recovery Plan (Document Availability (non-FR))
Endangered and Threatened Wildlife and Plants; 29 Draft Recovery Plan Revisions for 43 Species in th…
  • Publication type: Draft
Item 8