60 



bend); orbital processes lacking; zygomatic arches liiglily reduced, usually indetectable at 

 prepared skull. Skull base with elongate bony palate , the posterior edge reaching the 

 alisphenoid canal. Palate trapezoid m basal view (caninal width of the palate smaller than 

 molar width of the palate). 



Fig.47: Choeronycteris mexicana, a: skull dorsal view, b: mandible top view, c: skull lateral view 



Vomer covered by palatinimi, septimi continues as a presphenoid ridge up to the end of 

 the presphenoid. Alltogether, the base is stronger vaulted than in Choeroniscus. Pterygoids 

 lead into elongate, shovel-hke widened hamuli, diverging concavely and, together with the 

 tympanohyale, forming a bony contact with the bullae. 



Teeth: dental formula - 2 3 1 - - 3 4 5 6 7 



- - - 1 - 2 3 4 5 6 7 



Similar to Choeroniscus, but postcanine tooth row with larger interdental distances. 

 C. harrisoni (fig. 48): Skull: like C. mexicana, but its rostrum is even more elongate. Thus 

 both, the ridge of the nose and the mandibula, are still more convex and show a distinct 

 angle to the braincase (lacrimal inflation). In basal view, the palate appears elongate- 

 rectangular compared to C. mexicana. 

 Teeth: dental formula - 2 3 1 - - 3 4 5 6 7 



- - - 1 - 2 3 4 5 6 7 



Similar to C. mexicana, but the distances between the single teeth are even more 

 distinctly; the last of the molars is situated far anterior (^f the mandibular joint. 



10 mm 



Fig.48: Choeronycteris harrisoni skull, a: lateral view, b: frontal view 



