A group of closely related organisms, populations of which are distributed geographically in a ring-shaped cline, diverging in opposite directions and culminating in one point on the ring where two populations coexist but cannot interbreed.
Origin
1950s.
Definition of ring species in US English:
ring species
noun
Biology
A group of closely related organisms, populations of which are distributed geographically in a ring-shaped cline, diverging in opposite directions and culminating in one point on the ring where two populations coexist but cannot interbreed.