82 



Thus, witliin the resulting order of relative lengths of the maxillar tooth row (the smallest 

 value for quotients represents tlie longest tooth row) the dental formula which differs from 

 the original pattern of the subfamily (five postcanine teeth on one half of the upper jaw) 

 must be taken into consideration: in Leptonycteris and Lichonycteris there are two 

 premolars and molars each on one half of the upper jaw, and in Anoiuxi there are 6 teeth 

 in total forming the postcanine tooth row. In comparison, there is an extreme long tooth 

 row in Monophyllus. Though considered primitive by other characteristics, in this respect, 

 this genus is in no way inferior to the highly speciahzed species. 



3) Height of the braincase to palate length: Whereas total skull length in 1) certainly 

 shows a trend to muzzle prolongation, this will not be expected for height of the 

 bramcase. Size and shape of the braincase are determined primarily by brain morphology, 

 and in forms with strong masticatory musculamre there is an additional influence by the 

 musculamre originating at the braincase (Crista sagittalis). As the latter is weakly 

 developed in all Glossophaginae (revealing a decrease of masticatory function in food 

 intake), it does not influence the height of the braincase at all. 



Tlie position of Phyllostomus within the order of the quotients remains remarkable, 

 suggesting that the palate is relativly longer compared to braincase height - in this case, 

 tlie quotient is determined by the Crista sagittalis with an incomparable brain case height. 



4) Total skull length to coronoid height: The height of the coronoid process at the Ramus 

 mandibularis refers to masticatory functions of tlie species examined: here the M. 

 temporalis which is essential for efficient snapping, inserts at the mandible. As 

 specialization on nectarivory increases, tliis musculature becomes less important. The 

 quotient of total skull length and coronoid height mdicates which of the genera 

 experienced the most distinctive prolongation of the visceral skull witli a simultaneous 

 reduction of the masticatory fimction. 



5) Height of the braincase to coronoid height: Apart from the relation to total length, the 

 comparison of a quantity mdependent of rostrum prolongation as braincase height and 

 coronoid height does make sense as a measure reflecting the functional reduction of the 

 jaw apparatus: in this context, tlie otherwise very long-headed Platalina takes a basal rank, 

 and with a quotient of 2.12, Hylonycteris shares the same level with the unspecialized 

 genus Lionycteris (2.13). In contrast to the comparison SGL to CH, also Musonycteris has 

 shifted to a middle position, and Erophylla stands out with a quite flat mandible compared 

 to the hight of the braincase (2.17). These partly different orders in both quotients are 

 strongly determined by absolute skull size - the denominator - braincase size - is 

 comparatively larger in smaller individuals. Tliis supports once more the necessity of 

 performing allonietric comparisons, too. 



6) Mandible lengtli to coronoid height: The length of the mandible may be referred to as 

 a rehable measure for tlie lengtli of the viscerocraniuni. Setting mandible length to 

 coronoid height also results in a representative perspective for tlie extent of specialization 

 in the genera examined. The larger the quotient, the longer the mandible related to 

 coronoid height. In addition to its significance, the value of mandible length is reinforced 

 by the negative trend of coronoid height in the course of higher specialization on nectar 

 and poUen feeding. 



