65 



Height of braiiicase to palate length: iii order to cemipare measures being as independent 

 as possible of each other, the height of the braincase (MWx) is related to the length of the 

 palate (MWy): tab.7. 



Table 7: Proportion of mean height of braincase (MWx) / mean length of palate (MWy) 





X / y 



SD 





X / y 



SD 



Brachyphylla 



0.96 



0.05 



An our a 



0.65 



0.04 



Carollia 



0.94 



0.06 



Leptonycteris 



0.59 



0.02 



Phyllonycteris 



0.90 



0.03 



LonchophyUa 



0.59 



0.06 



Erophylla 



0.88 



0.03 



Choeroniscus 



0.56 



0.06 



Phyllostomus 



0.85 





Hylonycteris 



0.53 





Lionycteris 



0.82 



0.02 



Choeronycteris 



0.50 



0.02 



Uchonycteris 



0.74 



0.03 



Platalina 



0.49 





Monophylliis 



0.69 



0.05 



Musonycteris 



0.40 





Glossophaga 



0.69 



0.04 









Total skull length to coronoid height: with relative size of the coronoid process, the force 

 of the M. temporalis to move and hold the mandible against the upper jaw increases. 

 Thus, coronoid height is a morphological mdicator for masticatory pressure achieved by 

 tlie contracting M. temporalis. Tlie larger tlie Proc. coronoideus, the stronger the bite. 

 With respect to a fimctional shift to nectar feeding, also the proportions of coronoid height 

 (MWx) and total skull lengtli (MWy) may be mterestmg: tab. 8. 



Table 8: Proportion of mean coronoid height (MWx) / mean skull length (MWy) 





X / y 



SD 





X / y 



SD 



Phyllostomus 



0.25 





Leptonycteris 



0.16 



0.01 



Brachyphylla 



0.25 





An our a 



0.16 



0.35 



Phyllonycteris 



0.19 



0.01 



Monophyllus 



0.16 



0.01 



Erophylla 



0.18 



0.01 



Platalitia 



0.16 





Lionycteris 



0.18 



0.01 



Hylonycteris 



0.16 





Uchonycteris 



0.18 



0.02 



Choeronycteris 



0.14 



0.01 



Glossophaga 



0.18 



0.01 



Choeroniscus 



0.13 



0.01 



LonchophyUa 



0.17 



0.01 



Musonycteris 



0.12 





Height of braincase to coronoid height: to obtain a measure for the functional reduction of 

 the jaw apparatus, apart from the relationslnp to total length it may also be useful to 

 compare a quantity independent of rostrum prolongation, e.g. braincase height (Mwx) with 

 coronoid height (MWy), as with increasmg jaw length the coronoid process does not 

 necessarily grow at the same ratio. Only if a Crista sagittahs is present, the height of the 

 braincase gives evidence of a fimctional relation to the Ramus mandibularis. Otherwise, 

 this measure is affected essentially by the current morphology (and volume) of the brain 

 (tab. 9). 



