Spectaclecase

Cumberlandia monodonta is endemic to the Mississippi, Ohio, and Missouri River basins and is found most often in larger rivers. They are most commonly found in aggregated clumps within mild water, between large rocks and wedged into firm mud. C. monodonta take shelter from the current by clustering beneath slab boulders or bedrock shelves. Historically, C. monodonta has occurred in at least 44 streams within its three endemic basins. As of 2014, the mussel was known to occupy only 20 streams, representing a 55% decline in range. Furthermore, these populations are highly fragmented and cover only short stretches of a given river. The mussel's 5-Year Review reports that there has been no change in C. monodonta's range since its listing as Endangered. C. monodonta does not reside in any critical habitat. A map of C. monodonta's historical and present range can be found on its IUCN Red List web page.

Specific life history requirements of C. monodonta's life cycle are still widely unknown. The mussel is estimated to reach sexual maturity at 4- to 5-years-old for males and 5- to 7-years-old for females. The life cycle of C. monodonta consists of many steps. Males release sperm into the water, and females intake the sperm while filter feeding. The fertilized eggs will grow into larvae called glochidia. When the glochidia mature in early April to late May, the females will release them into the water column. Glochidia have a brief but mandatory parasitic stage on fish—two host species have been confirmed (Hiodon tergisus and Hiodon alosoides), but further research is being conducted to identify additional hosts.

Cumberlandia monodonta was first included in the "Review of Invertebrate Wildlife for Listing as Endangered for Threatened Species" in 1984. This list does not officially recognize species as endangered, threatened, or otherwise, but encourages species on the list to be more thoroughly researched in order to designate an Endangered Species Act listing. The IUCN listed Cumberlandia monodonta (under its synonym Margaritifera monodonta) as "Near Threatened" in 1996 and updated its status to "Endangered" in 2012. On March 13, 2012, The United States Fish and Wildlife Services officially declared the species as endangered due to its declining populations. A recovery outline was developed for C. monodonta in January 2014, but a full recovery plan has not yet been developed. Since the species was declared endangered by the Endangered Species Act, there have been no changes in its listing status.