Molossus molossus (Pallas, 1766)

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 : 144-146

Molossus molossus (Pallas, 1766)

Figure 37A

VOUCHER MATERIAL (TOTAL = 26): Jenaro Herrera (AMNH 278458; CEBIOMAS 90; MUSM 5536, 5943, 6663–6666, 6978), Nuevo San Juan (AMNH 272743, 272744, 272776– 272779, 273115; MUSM 13218–13221, 15234), Quebrada Blanco (MUSM 20983), Quebrada

Sábalo (MUSA 15226, 15227), Río Blanco (MUSA 15077, 15078); see table 63 for measurements.

UNVOUCHERED OBSERVATIONS: Many dozens of Molossus molossus were captured and released at Jenaro Herrera during the 2012 CEBIO bat course, and we captured another 15 individuals at El Chino Village in 2019.

IDENTIFICATION: Molossus molossus is a widespread taxon that belongs to a species complex with several other taxa previously treated as subspecies or synonyms; in its current, strict sense, M. molossus is now thought to range from southern Mexico to northern Argentina, including the Lesser Antilles (Loureiro et al., 2018a, 2019). Molossus molossus is distinguished from other congeneric species by its medium size (forearm 35–43 mm, greatest length of skull 15–19 mm); long (> 4 mm), bicolored dorsal fur, varying from cinnamon to cocoa brown; triangular or rounded occipital complex with underdeveloped lambdoidal crests; a low sagittal crest; and elongate upper incisors with parallel tips (Eger, 2008; Loureiro et al., 2018a). Descriptions and measurements of Molossus molossus were provided by Husson (1962, 1978), Dolan (1989), Ascorra et al. (1993), Simmons and Voss (1998), Barquez et al. (1999), Reid (2009), Lim and Engstrom (2001b), Lim et al. (2005), Barros (2014), Catzeflis et al. (2016), Giménez and Giannini (2016), and Loureiro et al. (2018a, 2018b). As noted above, multiple subspecies were traditionally recognized in M. molossus (e.g., by Simmons, 2005; Eger, 2008), but several have now been removed to other taxa (Loureiro et al., 2019). There is current disagreement concerning trinomial usage for the populations that occur east of the Andes in Peru: Simmons (2005) indicated that these should be called M. m. molossus , whereas Eger (2008) placed them in M. m. crassicaudatus. Although recent molecular studies support Simmons’ nomenclature (Lindsey and Ammerman, 2016; Loureiro et al., 2018b, 2019), a comprehensive review of the species is needed, preferably based on analyses that include sequence data from holotypes or topotypic specimens of all nominal taxa currently treated as synonyms or subspecies.

Ascorra et al. (1993), Fleck et al. (2002), and Medina et al. (2015) correctly identified their specimens from Jenaro Herrera, Nuevo San Juan, Quebrada Sábalo, and Río Blanco as Molossus molossus . Most of the voucher material we examined from the Yavarí-Ucayali interfluve conforms to previous descriptions and measurements of the nominotypical subspecies, but one of our vouchers (AMNH 278458) is an albino (Tello et al., 2014).

REMARKS: Of 192 recorded captures of Molossus molossus accompanied by ecological data from our region, 83 were made in ground-level mistnets and 109 in elevated nets. Most (187) of these mistnet captures were made in clearings around buildings, but 2 were captured over a stream and 3 were captured above secondary vegetation. Both of the roosts we encountered were in buildings. Vast numbers (perhaps hundreds) of these bats sheltered between the ceiling and the roof of the school at Nuevo San Juan, and most (if not all) of the 35 individuals that we mistnetted there on 21 June 1998 had probably just emerged from the schoolhouse (our nets were set between the school and the river at dusk in anticipation of the event). At El Chino, we captured two individuals from a larger group that was roosting in a crack between the rafters and the roof of the village school, and it is likely that most of the 139 individuals mistnetted in clearings at Jenaro Herrera had emerged from roosts in nearby station buildings that they are known to inhabit (Ascorra et al., 1993).

Figures

FIG. 37. Photographs of A, an adult Molossus molossus and B, an adult M. rufus, both captured at Jenaro Herrera. Photographs by Marco Tschapka.