63 



Statistically, oiily those random samples comprising nmnerous individuals can be 

 processed, whereas rare species with little material available may only be referred to by 

 individual records. 



Sex-specific differences 



Withiii the genus Phyllostomiis (examined as outgroup), in the extremely large species P. 

 hastatiis, most of the male skull measures examined rank over the female ones (see 

 appendix). 



hi all species of the genus Choeroniscus the cranial length values of the females proved 

 statistically significantly larger than those of the corresponding males (p < 0.05, t-test). 

 hi Lonchophylla wbiista the only available male was distinctly larger than the females 

 examined - in contrast to the smaller species of the genus. In L. handleyi which is even 

 larger, in 12 of 17 parameters the male values on average exceed the female ones, too, 

 although in the given random samples this could not be secured statistically. In all the 

 remaining taxa the sexes did not show any significant differences in tlieir skull measures. 



Skull proportions 



Tlie extent of adaptation to nectarivory may be expressed by the relation of rostmm length 

 to total skuU length, as the following measure relations give evidence: 



- Total length of skull to length of palate. 



- Total length of skull to upper tooth row. 



- Height of braiiicase cranium to length of palate. 



- Total skull length to coronoid height. 



- Height of braincase cranium to coronoid height. 



- Mandible length to coronoid height. 



Total length of skull to length of palate: the quotient of the means for the total skull 

 length (MWx) and the length of the bony palate (MWy) gives a good idea of relative 

 muzzle lengtli m the species examined (the larger the quotient, the shorter the palate) 

 (tab.5, fig.49). 



Table 5: Proportion of mean total skiill length (MWx) / mean palate length (MWy) 





X / y 



SD 





X / y 



SD 



Phyllonycteris 



2.30 



0.08 



Anoura 



1.83 



0.07 



Erophylla 



2.24 



0.07 



Leptonycteris 



1.77 



0.05 



Carollia 



2.28 



0.04 



Lonchophylla 



1.73 



0.08 



Lionycteris 



2.08 



0.04 



Choeronycteris 



1.61 



0.05 



Monophyllus 



1.95 



0.07 



Hylonycteris 



1.57 



0.02 



Glossophaga 



1.83 



0.06 



Choeroniscus 



1.57 



0.08 



Lichonycteris 



1.83 



0.07 



Musonycteris 



1.50 





