COSEWIC assessment and update status report on the Northern Leopard Frog Lithobates pipiens, Rocky Mountain population, Western Boreal/Prairie populations and Eastern populations, in Canada.
Committee on the Status of Endangered Wildlife in Canada, Ottawa. vii + 69 pp. (www.sararegistry.gc.ca/status/status_e.cfm)
The Northern Leopard Frog (Lithobates pipiens) is 60 to 110 millimetres in length, with females generally larger than males. It may be either green or brown on the dorsal surface, which is covered with large, rounded dark spots outlined with light halos. The underside is white. Two light-coloured dorsolateral ridges line its back, one on each side, from behind the eyes to the lower back.
Three designatable units (DUs) are recognized in order to accurately portray the status of the Northern Leopard Frog in Canada. These are based on evidence for genetic distinction between western and eastern populations and the isolation of populations west of the Rocky Mountains. The Rocky Mountain DU consists of populations in British Columbia. The Prairie/Western Boreal DU contains the populations in the Alberta, Saskatchewan, the Northwest Territories and Manitoba approximately west of the Canadian Shield. The Eastern DU consisting of all those populations of the Canadian Shield, Great Lakes/St. Lawrence, Appalachian/Atlantic Coast and Carolinian faunal provinces.