Figure 1. A female colugo with her infant, depicted in a naturalistic pose. Note the expansive patagium and the unusual hanging posture. Living dermopterans cannot employ the typical quadrupedal postures that characterize most mammals because of numerous specializations in their fore- and hindlimb skeleton. Illustration by Mark Klingler.

Figure 2. Alternative phylogenetic reconstructions for dermopterans and their close relatives. (a) A traditional phylogenetic reconstruction showing close evolutionary relationships between tree shrews (Scandentia) and primates on the one hand, and dermopterans and bats (Chiroptera) on the other. (b) A more plausible phylogenetic reconstruction showing a close evolutionary relationship between tree shrews (Scandentia) and Primatomorpha, the supraordinal group that includes primates and dermopterans. Note that bats (Chiroptera) are not necessarily thought to be closely related to these animals. (c) The same phylogenetic tree as in (b), but with the addition of fossil dermopteran taxa (denoted by daggers). The acquisition of gliding behaviour in dermopterans occurred at the point on the tree designated by a star, after the common ancestors of paromomyids and living flying lemurs split away from the plesiadapid lineage. Accordingly, the evolution of gliding in dermopterans postdates their divergence from all other living mammals, and has no bearing on the evolution of flight in bats.