Notes on patagium morphology in the Gliding Flat-tailed House Gecko (<i>Hemidactylus platyurus</i>)

Several species of geckos have independently evolved patagia, membranous features that facilitate gliding.Detailed morphological investigations of gecko patagia have largely been limited to gliding members of the genus Gekko(formerly in the genus Ptychozoon). Herein we describe the morphology of gliding patagia of the Flat-tailed HouseGecko (Hemidactylus platyurus), a species with an independent evolutionary origin of gliding patagia from Gekko andan important species for researching gliding biomechanics. We compared morphology of H. platyurus with a closelyrelated non-gliding species, the Common House Gecko (Hemidactylus frenatus). Using external examination and histologicaltechniques, we compared and contrasted three regions that exhibit patagia (trunk, femoral region, and tail)in H. platyurus but not in H. frenatus. We find that patagia in a gliding Hemidactylus, like patagia in gliding membersof the genus Gekko, are derived from expansion of lateral fat bodies, suggesting analogous processes to achieve similarphenotypic outcomes.