Mammals. Chapter 28. Class Mammalia. Mammals, class Mammalia , are represented by more than 5,000 species. Kitti’s hognosed bat from Thailand weighs 1.5 g. Blue whales exceed 130 metric tons. Derived Characters of Mammals.
October 2, 2009 issue of Science is full of articles on Ardipithicus ramidus. Available for free! http://www.sciencemag.org/ardipithecus/