1. Forearm ≥ 35.0 mm; hairs between the shoulders ≥ 9 mm; dermal papillae on chin arranged in a V and separated by a wide basal cleft; metacarpal V longer than metacarpal IV; rostrum broad; lateral margin of infraorbital foramen does not project beyond rostral outline in dorsal view; outer upper incisors large; P5 lingual cusp weakly developed.......................................................................... Hsunycteris dashe

1′. Forearm ≤ 34.5 mm; hairs between the shoulders ≤ 8 mm; dermal papillae on chin arranged in a V but not separated by a wide basal cleft; metacarpal V shorter than or subequal to metacarpal IV; rostrum narrow; lateral margin of infraorbital foramen does project beyond rostral outline in dorsal view; outer upper incisors small; P5 lingual cusp well-developed..............................................................2

2. Postorbital region with a lateral projection; M1 parastyle weakly developed; lower incisors large and broad; m1 paracristid notch strongly developed; m2 hypoconid wide...................................................................... Hsunycteris cadenai

2′. Postorbital region lacks a lateral projection; M1 parastyle well developed; lower incisors small and narrow; m1 paracristid notch weakly developed or absent; m2 hypoconid narrow....................................................................... 3

3. Metacarpal V shorter than metacarpal IV; extent of maxillary posterior to M3 less than the length of M3; dentary slender; angular process narrow; P4 lingual cusp absent; P5 lingual cusp narrow.................................................. Hsunycteris pattoni

3′. Metacarpal V subequal to metacarpal IV; extent of maxillary posterior to M3 greater than the length of M3; dentary deep; angular process broad; P4 lingual cusp present; P5 lingual cusp broad.................................................... Hsunycteris thomasi