97 



I suppose will mainly have encouraged Tliomas in classifying this species in a genus of its 

 own, is meanwhile linked by L. handleyi wliich Hill described m 1983. 



2. Choeroniscus, Hylonycteris and Choeronycteris differ from the remaining 

 Glossophaginae in essential construction prmciples: with reference to skull morphology, 

 Choeronisciis resembles Hylonycteris by its airorhynchic skull; on the other hand (in con- 

 trast to Hyloncteris) Choeronisciis and Choeronycteris share extremely elongate pterygoid 

 processes as well as considerably flatter ramus mandibulares. By allometrical comparison, 

 all three genera give evidence of a transposition of the allometric line m tlie ratio of SIZE 

 to palate length: although palate lengtli increases with growing total skull lengtli by the 

 same factor as in other Glossophaginae, the allometric Ime (reduced major axis) nms 

 parallel but on a higher level. So, even in tlie smaller Choeronisciis godmani, relative 

 length of the palate clearly exceeds that of an equal-sized Lichonycteris. 

 Wliereas Hylonycteris in allometric comparison behaves almost identical to Choeronisciis 

 in four of the measmes examined (CC, GL, OZR, UKL), allometric analysis of the 

 relation of SIZE to coronoid height reveals a different development of the Ramus 

 mandibularis wliich would have been overlooked by merely examining the skuUs 

 individually. Although, like other Glossophaginae even Hylonycteris has a comparatively 

 flat mandible, in Choeronisciis and Choeronycteris this flattening developed to a more 

 advanced level, distinctly demarcated by the integration constant. 

 These data on skull morphology and allometry allow to differentiate four predommantly 

 nectarivorous subfamilies within the PhyUostomatidae: these are the Brachyphyllinae imd 

 PhyUonycterinae endemic to tlie Antilles Islands as well as the Lonchophyllinae and 

 Glossophaginae (having been sunmiarized as Glossophaginae by other authors). Hiis 

 systematic subdivision is in accordance with Griff itlis (1982). 



Within the Glossophaginae sensu strictu tlie tribe Clioeronycterini comprising the genera 

 Hylonycteris, Choeronisciis and Choeronycteris (incl. subgenus Miisonycteris) represents 

 an extremely liigh specialized group of nectar feeders. 



SUMMARY 



SkuU morphology of 13 New World nectarivorous bat genera was analyzed under 

 fimctional aspects and compared with individuals from systematically neighbouring 

 subfamilies of the PhyUostomatidae (CaroUiinae, Phyllostominae) . 



Tlie nectarivorous flower bats are characterized by special adaptations to this diet, 

 primarily imposing cranially by rostral prolongation to various extent. The degree of tliis 

 prolongation varies considerably within and between individual genera and can be judged 

 as an evidence of the extent of feeding specialization. Species takhig varied diet 

 {Glossophaga, Lionycteris) have shorter jaws tlian liiglily specialized nectar feeders 

 {Choeronycteris) whose palate length reaches half the total skull length. These proportions 

 are, however, also itifluenced by body size: small species possess relatively larger 

 braincases and shorter jaw lengtlis, larger specimens relatively smaller braincases and 

 longer jaws, respectively. 



By means of 17 measures, skiUl proportions as well as their allometric conditions 

 (gradient of tlieir reduced major axes, integration constants) were compared among the 

 genera examined (total number of specimens: 265). 



