188 Evolution? The Fossils Say YES!
or Permian, ask a fusulinid expert to look at it, and you will get the most precise estimate
possible.
There are many other examples of dramatic transformations in the forams that could be
shown. For example, in the Pliocene, one of the common planktonic forams is Globigerinoi-
des sacculifer (Kennett and Srinivasan 1983), which has a shell shaped like a series of porous
(A)(B)FIGURE 8.4. (A) Fusulinids evolved very rapidly during the late Paleozoic (Pennsylvanian and Permian) by
developing increasingly more complex chambers and wall structure, and a variety of shapes based on the
fundamental plan of a spiral shaped like a spindle. (B) Some photos of fusulinids at natural size. (Modified
from Boardman et al. 1987; courtesy Blackwell Scientific Publications)