Valvata virens (Tryon)
|Emerald Valve Snail
USA: Lake County; Santa Cruz County / California
|local name: -|
extinction date: (?)
|It seems not fully resolved,
where exactly this species occurs / occurred, thus, depending on which author, also
Nevada, Oregon and other states of the USA are given as home of this
More precise researches of the known collection specimens seem to indicate merely two localities in California, one of them is the Clear Lake in the Lake County, the second one is located near the town of Watsonville in the Santa Cruz County, but, however, seems not to be exactly determinable anymore.
The Clear Lake nowadays is heavily polluted and populated with numerous non-native species - recent collections of the Emerald Valve Snail are lacking and it is considered very possibly extinct.
- Peter Hovingh: Intermountain Freshwater Mollusks, USA (Margaritifera, Anodonta, Gonidea, Valvata, Ferrissia): Geography, Conservation, and Fish Management Implications. Monographs of the Western North American Naturalis 2: 109-135. 2004