Studies on the Two New Zealand Bats
Mystacina is not, as far as can be ascertained, a crevice dweller, and the extreme protection of the delicate membranes from possible injury correlated with a maximum degree of freedom for the limbs must be interpreted in relation to terrestrial locomotion. Similar protection of wing membranes occurs in the molossid Cheiromeles torquatus with the wing tips being folded into pouches, but here the pouches are in the armpits and open backwards (Kitchener, 1954). In the molossids the ability to crawl rapidly is possibly an adaptation related to roosting. Eumops, for instance, is unable to take flight from a level surface (Vaughan, 1959). In Mystacina freedom of the limbs provided by the reduced propatagium and wing folding process, the robust limbs, the specialized claws, and the wide range of movement of the femur permitted by the form of the acetabulum are terrestrial or arboreal adaptations. The ability to take flight from level ground has been recorded for Mystacina and terrestrialism in this bat is not connected with roosting but is rather to be associated with foraging habits. The scanty information available pertaining to the ecology of this species does appear to substantiate Dobson's earlier conclusions.
Abbreviations: 3m, 4m, 5m, metacarpals of digits 3, 4 and 5; 3 ph. 1, 3 ph. 2, 3 ph. 3, phalanges of digit 3; 4 ph. 1, 4 ph. 2, phalanges of digit 4; 5 ph. 1, 5 ph. 2, phalanges of digit 5.