Coelocanth (Latimeria chalumnae)

Coelocanths are members of a group of lobe-finned fishes called Crossopterygia, thought to have been extinct since the Mesozoic. Rediscovered in 1938 by Marjorie Courtenay Latimer, Latimeria combines ancestral (hollow spines, fleshy fins) and derived (marine habit, "lung" filled with fat) characters, and as such is an excellent example of mosaic evolution. The largest known population is near the Comoro Islands between Mozambique and Madagascar; a second species, L. menadoensis,  has recently been discovered near Sulawesi in Indonesia (see http://www.dinofish.com)