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Sucker Family- 
                Catostomidae 
  Nineteen species of suckers in 8 genera are known from Wisconsin. 
The suckers are a compact group of 12 living genera and about 60 spe- 
cies, essentially North American. In the United States and Canada, 59 
species are listed in 11 genera (Robins et al. 1980). Only two representa-
tives are found in eastern Asia-an ancient monotypic genus in China 
(Myxocyprinus), and Catostomus catostomus; the latter represents a recent
invasion of a species widespread in northern North America. 
  Fossil remains of suckers have been taken from deposits in British Co-
lumbia, Nevada, and Colorado. The earliest reliably dated remains of the
family in North America are from the Eocene, and are some 55 million 
years old (Miller 1959). It is believed that suckers arose in southeastern
Asia and soon crossed a Bering land bridge to America, leaving a relict 
in China. 
  It is generally held that the suckers are ancestral to (or at least more
primitive than) the minnows; however, Eaton (1935), while studying the 
upper jaw mechanism in the bony fishes, concluded that suckers de- 
scended from minnows. The fact is that suckers are closely related to 
minnows, and frequently appear confusingly minnowlike. 
  The sucker family is readily distinguished from native minnows by a 
difference in the distance from the front of the anal fin to the base of
the 
caudal fin. In suckers, this distance is contained more than 2.5 times in
the distance from the front of the anal fin to the tip of the snout; in 
minnows, the anal-caudal distance is contained fewer than 2.5 times in 
the distance from the anal fin to the snout tip. Old World minnows, such
as the carp and the goldfish, resemble suckers in this respect, but may 
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