77 



for Lionycteris within the LonchophyUinae and for Glossophaga within the Glossopha- 

 ginae. 



Within the genus LonchophyJla there are aheady some species with relative long rostra; L. 

 thoniasi has a comparatively short rostnmi; this feature, however, depending on body size: 

 witliin each genus, relative rostmm length increases allometrically witli body size. Tlie 

 longest rostnmi of all LonchophyUinae is found in the genus Platalina with the palate 

 length comprising more than half of the total skull length. 



Also within the Glossophaginae, the smaller species show relatively short rostra 

 (Lichonycteris obsciira, Choeroniscus godmani). There are, however, considerable 

 differences between genera of equal size {Leptonycteris and Choeronycteris). As an 

 extreme, the Mexican banana bat Choeronycteris harrisoni has the longest rostrum (in 

 relative and absolute terms) among all nectar feeding bats. 



Since rostrum length is emphasized, the development of the forehead is increasingly 

 restricted: interorbital and postorbital width are relatively small and, in the extreme case, 

 no longer distinguishable from each other any more. Similar to other extremly long-jawed 

 mammals (cf . Myrmecophaga) the Glossophaginae lack a demarcation from the orbitae by 

 visible orbital processes. 



Zygomatic arches 



Reduction of the zygomatic arches corresponds to the significance of the masticatory 

 musculamre wliich is reduced with increasing specialization. These structures are often 

 damaged during preparation or inadvertently totahy removed (in Husson 1965, the missing 

 zygomatic arches were erroneously recorded as a determination feature within the 

 Glossophaginae sensu strictu). Whereas neither the Carolliinae nor the LonchophyUinae 



Forehead 



Brachyphylla 

 (fhigivorous) 



HKB 



MB 



(nectarivorous) 



Choeroniscus 



Fig. 56: Skulls of bats with 



different diet. 



JOB = interorbital width 



POB = postorbital width 



HKB = width of braiiicase 



MB = mastoid widtli 



C.s. = crista sagittal is 



