Over-specialization with no adaptive value sometimes occurs (Talk.Origins)
Evolution says that complex structures would not be formed without a selective advantage for them. But overspecialization with no adaptive value sometimes occurs. An example is the enormous antlers of the Irish elk. Despite the seeming disadvantages, animals with such extreme features seem to do as well as other animals.
- Macbeth, Norman, 1971. Darwin Retried. Boston: Delta, pp. 70-73
Talk Origins has a good point on this claim; however it is not commonly used, and would seem to only be used by the cited source.