IUCN threat status:

Least Concern (LC)


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Range Description

This northern species has a range extending from Indiana and Michigan to southeastern Minnesota, Iowa, southeastern Kansas, Missouri, Oklahoma, Arkansas and Kentucky, and has apparently been extirpated from Ohio. Van der Schalie and van der Schalie (1963) had expressed concern that it might be endangered in Michigan, but Hoeh (pers. comm. 2010) stated that his field experience suggested that it may be faring well. Out of 28 stations recently surveyed along the Tittabawassee River of Michigan, a tributary to the Saginaw, the species was present at 16 and abundant at eight stations (Hoeh pers. comm. 2010). Currently, the species is found at eleven sites in five southeastern Wisconsin river systems. It also occurs in the Fox River drainage in the southwestern part of the state. (Mathiak 1979, K. Cummings pers. obs. 2010). In Kansas, range is restricted to the Spring River in the southeastern corner of the state and the mussel is considered a peripheral species (Mathiak 1979, Busby pers. comm. 2010). In Missouri, the range formerly covered areas north of the Missouri River. Current range is the streams that flow north off the Salem and Springfield Plateaus (Oesch 1984, 1995). The first record from Minnesota was from the Cannon River in 1987 (Davis 1987). Within the Cannon River watershed, extant populations were discovered in the Straight River, Wolf Creek and the Cannon River proper. The largest population was found within the tailwaters of an old mill dam on the Straight River (Davis 1987) and although recent survey efforts did not discover this species there (Swift and Wagenbach 1999), Hove et al. (2005) found 2 live and 3 dead shells in June 2005. Although presently limited in distribution within the drainage, past distribution appears to have been much wider. Subsequent to the Cannon River survey, sites have been found in other river systems within the southeastern corner of the state, the Zumbro (Bright pers. comm. 2010) and tributaries to the Root (Ostlie pers. obs. 2010). Allen et al. (2007) compiled data from 1800 sample sites across all of Minnesota (almost 500 from the St. Croix drainage and drainages in southeastern Minnesota) and found the species in 219 sites in five primary tributaries to the Mississippi River: the Cannon, Cedar, Root, Upper Iowa, and Zumbro River systems; with no relic shells in any other systems. Allen et al. (2007) also discounted other records from outside these areas including specimens from the St. Croix River proper (see Graf 1997). In Iowa, range is the upper reaches of rivers in the northeastern third of Iowa (Frest pers. comm. 2010, Howell pers. comm. 2010). Although some records are available from large rivers (judging from recent records of this species from the Mississippi River at Davenport, Muscatine, Prairie du Chien and Keokuk, Frest, Pers. Comm. 2010) it is rarely found in large river habitats. There have been no records in the state of Ohio (Hoggarth pers. comm. 2010). Sterki (1907) recorded the species from the Ohio River, but that record did not come from the Ohio portion of the river (Hoggarth pers. comm. 2010). Although some records also exist in Lake Erie tributaries, none of these are from Ohio. The ellipse was historically found in the northern half of Illinois, particularly in the northeast. However, many streams in that part of Illinois have been negatively effected by urban development and agricultural impacts and many populations have been extirpated. The ellipse is now relatively uncommon in Illinois. A few apparently healthy populations can still be found in tributaries to the Kankakee, Fox, Mackinaw, and Vermilion (Illinois River drainage) rivers. This mussel is rare in Indiana occurring only at a few sites primarily in streams draining into Lake Michigan. A few historical records exist for glacial lakes in the headwaters of the Tippecanoe River (K. Cummings pers. obs. 2010).


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© International Union for Conservation of Nature and Natural Resources

Source: IUCN

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