Micronycteris (Micronycteris) microtis Miller, 1898

Velazco, Paúl M., Voss, Robert S., Fleck, David W. & Simmons, Nancy B., 2021, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 4: Bats, Bulletin of the American Museum of Natural History 2021 (451), pp. 1-201 : 61

Micronycteris (Micronycteris) microtis Miller, 1898

VOUCHER MATERIAL (TOTAL = 28): Nuevo San Juan (AMNH 272856, 273072, 273081, 273098, 273123, 273134, 273148, 273149, 273163, 273169, 273170, 273190, 273192; MUSM 13210–13212, 15218–15226, 15230, 15232, 15233); see table 28 for measurements.

UNVOUCHERED OBSERVATIONS: None.

IDENTIFICATION: Micronycteris microtis is widely distributed from southern Mexico to northern Argentina (Williams and Genoways, 2008; Díaz and Barquez, 2009; Reid, 2009; Moras et al., 2015). Our material represents the first record of this species in Peru. Micronycteris microtis can be distinguished from other congeners by external and craniodental features including: ear <22 mm; fur on lower third of leading edge of pinna ≤ 8 mm in length; dorsal fur between the shoulders <11.5 mm in length; calcar longer than foot; forearm <36.5 mm; first and second upper premolars subequal in anteroposterior length; height of first upper premolar very slightly less than that of second upper premolar; and first, second, and third lower premolars similar in size (Simmons and Voss, 1998; Moras et al., 2015). Descriptions and measurements of M. microtis have been provided by Brosset and Charles-Dominique (1990), Simmons (1996), Simmons and Voss (1998), Lim et al. (1999), Larsen et al. (2011), and Moras et al. (2015). Two subspecies are currently recognized: M. m. mexicana ( Mexico to western Costa Rica) and M. m. microtis (eastern Nicaragua to South America) (Simmons, 1996).

Fleck et al. (2002) and Moras et al. (2015) correctly identified their material from Nuevo San Juan, which conforms to previous descriptions of Micronycteris microtis and has measurements that fall within the previously documented range of size variation for the species. However, one individual from this series (AMNH 273169), which has a cytochrome b genetic distance of 4.7% from Brazilian samples of M. microtis , was identified as “ M. sp.” by Porter et al. (2007), as “ M. sp.” and M. megalotis by Larsen et al. (2011), and as M. microtis and “ M. sp.” by Siles et al. (2013). These taxonomic discrepancies reflect ongoing uncertainty about species limits among the dark-bellied forms of Micronycteris . Pending resolution of these issues with more extensive sampling and additional molecular markers we recognize the Nuevo San Juan material as M. microtis based on the phenotypic data at hand.

REMARKS: We captured one individual of Micronycteris microtis in a ground-level mistnet in secondary vegetation near Nuevo San Juan, but the 27 other specimens from this locality were taken from roosts (table 29). Most roosts were in tunnellike shelters (hollow logs or animal burrows), but occasionally also in cavities in standing trees; all roosts were found at or near ground level. Most roosts were in well-drained primary upland forest (typically on hill slopes or hillcrests), but one was in secondary vegetation in an old blowdown. Micronycteris microtis was usually found roosting alone, but one roost was shared with M. hirsuta , and five roosts were shared with Carollia brevicauda .

Hollow logs are the commonest roost type from which this species has been reported at Amazonian localities (Voss et al., 2016).