ADAPTATION AND EVOLUTION IN THE HAND MUSCLES OF AUSTRALO-PAPUAN HYLIDFROGS (ANURA, HYLIDAE, PELODRYADINAE)

Members of the Pelodryadinae possess a hitherto undescribed set of dis tal extensor muscles to the ultimate phalanges; this set is found also in the hyline frogs that formed an outgroup for this study, and also in scansorial but not terrestrial microhylids. The M. palmaris longus of Cyclorana consists of two slips, whereas in most other pelodryadine s the division is three-fold. The problematic species Litoria albogutt ata and L. dahlii exhibit the Cyclorana condition. The hand musculatur e of Litoria infrafrenata is typical of its genus, and this study give s no support to the hypothesis that this species has evolved independe ntly of the other pelodryadines; however, there is support for the hyp othesis that montane New Guinean Litoria are closely related to some m embers of the freycineti assemblage of mostly terrestrial frogs. The h and musculature of Nyctimystes possesses no features to distinguish it from that of a generalised Litoria species, and sheds no light on the origins of Nyctimystes.