Epioblasma obliquata

Epioblasma obliquata

Critically Imperiled  (NatureServe)[1]
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Unionoida
Family: Unionidae
Genus: Epioblasma
Species: E. obliquata
Binomial name
Epioblasma obliquata

Epioblasma obliquata, commonly called the catspaw, is a species of freshwater mussel. It is native to eastern North America, where it is classified as Endangered under the Endangered Species Act.

Natural History and Conservation

This species was historically widespread in the Ohio River and Great Lakes drainage basins. Like many other North American freshwater mussels, it relies on a habitat of shallow, gravelly riffle zones in larger rivers. This oxygen-rich habitat has largely been destroyed over the past 200 years by dam construction and dredging, which caused a massive population decline.[1]

Both subspecies are critically endangered. By the time E. obliquata obliquata, the purple catspaw, was listed in 1990 under the Endangered Species Act, no surviving breeding populations were known. This changed in 1994 when a few young individuals were found in Killbuck Creek, Ohio, indicating a small breeding population. An attempt to collect young individuals was made in order to start a captive breeding program. However, to the researchers disappointment, surveys from 2006-2007 recorded a population of only 12 males and zero females. It wasn't until 2012 that researchers were able to find their first female individuals that could be used for captive breeding programs, which are now underway.[2][3]

The purple nacre is characteristic of subspecies obliqua, the purple catspaw

The status of subspecies E. obliquata perobliqua, the white catspaw, is more dire. Only a single population has persisted into the modern day, found in Fish Creek, a tributary of the St. Joseph River in Indiana. At this location, only five living individuals were documented during surveys from 1975 to 1999, with the last living female recorded in 1975. Since then, surveys of Fish Creek have failed to find any living white catspaw mussels.[4]

Subspecies

This species exhibits variable shell characteristics, which have been taxonomically treated as either subspecies or separate species. The latter approach is not favored by modern taxonomists due to its reliance on shell color, which is a poor distinguishing character.[1]

  • Purple catspaw (Epioblasma obliquata obliquata)
  • White catspaw (Epioblasma obliquata perobliqua)

References

  1. 1 2 3 NatureServe
  2. ↑ Scientific American John R. Platt
  3. ↑ Purple Catspaw 5-year Review U.S. Fish and Wildlife Service, April 2015
  4. ↑ White Catspaw 5-year Review U.S. Fish and Wildlife Service, April 2009
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