charismatic megafauna
n. Animals that have popular appeal and so can form the basis of conservation campaigns and fundraising drives.
Examples
1999
Giant pandas are 'charismatic megafauna,' a category that includes whales and other sea mammals, salmon and other inspirational fish, eagles and other flashy raptors. In each instance, the creatures help spotlight the hundreds of humbler but equally endangered species: the black-spored quillwort, the longhorn fairy shrimp.
—“Birth and Rebirth,” USA Today, August 23, 1999
1985 (earliest)
Most people, if ever exposed, remember and are able to name elephants, tigers, bears, rhinoceroses, and gorillas. The giant panda probably tops this list of charismatic megafauna in terms of attractiveness and mass appeal.
—Devra G. Kleiman, “The giant pandas of wolong,” Science, May 17, 1985
Notes
There's nothing all that new about this phrase (it's been seen in print since about the mid-80s), but when subscriber Viki Bankey told me about it, some obscure area of my fancy was tickled enough to want to post it. While researching this phrase, I came across some less-scientific substitutes: glamour animals, heroic species, and flagship species.