Micronycteris sp.

3.2 Morphological diagnosis of the specimen Micronycteris sp.

At first, we thought that specimen MPEG 37789 was of the rare species N. pusilla , last recorded over 70 years ago. However, upon closer examining and, comparing with the holotype of N. pusilla (AMNH 78830), we realized that it belongs to the genus Micronycteris , but it does not match morphological characters of the currently recognized species. Our specimen, a female (MPEG 37789) ( Figures 4 View Figure 4 and 5 View Figure 5 ), seems to belong to the informal group of dark-bellied Micronycteris ( Simmons 1996) . Its morphological characteristics include: self-colored orange-reddish fur color on both ventral and dorsal sides ( Figure 4A View Figure 4 ), forearm length of 34.72 mm, ears rounded and separated by small flaps ( Figure 4B View Figure 4 ), ear length of 18.70 mm, short hairs on the inner edge of ears ( 3 mm), finely rounded nose leaf shape, 3rd metacarpal shorter than the 4th metacarpal, longest skull length of 18.37 mm, developed mandibular 3rd premolar, absent mandibular 4th premolar, and a tooth formula I 2/2, C 2/2, P 2/3, M 3/3.

Craniodental characters, such as the upper external incisors visible to the naked eye and the developed upper premolars, can be observed in Figure 5 View Figure 5 . Unfortunately, this specimen was not well-preserved, and its very fragile skull was broken and fragmented.