Pteronotus gymnonotus

Field: Agricultural and Biological Sciences (Life Sciences)

5. Big Naked-backed Bat Pteronotus gymnonotus French: Ptéronote a dos nu / German: GroRe Nacktrlickenfledermaus / Spanish: Pteronotus de espalda desnuda Taxonomy. Chilonycteris gymnonotus [sic] Wagner, 1843, “Cuyaba [= Cuiabd],” Mato Grosso, Brazil. Some authors attribute the name P. gymnonotus to J. B. Natterer. When J. D. Smith in 1977 clarified the nomenclatural history recognizing P. gymnonotus as the senior synonym of P. suapurensis, he assigned Natterer as its authority. Smith argued that J. A. Wagner, when he described P. gymnonotus, attributed the name of the species to Natterer because the descriptive notes were taken directly from Natterer’s field diary. D. C. Carter and P. G. Dolan in 1978 examined a photocopy of Natterer’s field notes and stated that, even though Wagner used Natterer’s species name, he wrote the species diagnosis independently, and therefore Smith’s claim was not supported. Carter and Dolan’s argument is followed here. Fossil records of P. gymnonotus are reported from Tobago Island. Monotypic. Distribution. From S Mexico S along Central America, Caribbean coast of South America, and the Guianas to C & NE Brazil, E Peru, and NE Bolivia. Descriptive notes. Head-body ¢.51-69 mm, tail 17-27 mm, ear 13-20 mm, hindfoot 9-13 mm, forearm 50-56 mm; weight 12-18 g. The Big Naked-backed Bat is the largest species of naked-backed bat, both externally and cranially. Fur color varies from dark brown to bright orange and is paler ventrally than dorsally. There are short hairs densely covering fused wing membrane, giving back a “velvety” appearance. Skull rostrum is conspicuously shorter than one-half total length of skull and very broad, with depressed nasals. Braincase is oblong, and basioccipital region between bullae is very broad. Condylo-basal lengths are 15-17 mm. There is a geographical trend of larger overall sizes in the northernmost distribution, but no population structuring at the molecular level is observed. Additional external and cranial features shared with other species in the subgenus Pleronotus are listed in descriptive notes for Davy’s Naked-backed Bat (P. davyr). Habitat. Tropical rainforest, dry forest, xerophytic scrub, and savannas. The Big Naked-backed Bat is more abundant in dry and semi-open environments below elevations of 400 m, although there are several records from the Brazilian central plateau above 1000 m. Food and Feeding. Diets of Big Naked-backed Bats include moths, beetles, flies, and crickets. Breeding. In Nicaragua and Mexico, pregnant Big Naked-backed Bats were reported in April, May, and June. In north-eastern Brazil, it has been suggested that the reproductive pattern is related to the wet season, with pregnant females reported in September—November. Activity patterns. The Big Naked-backed Bat forages more commonly in semi-open areas and over water bodies. Echolocation calls during search phase consist of short CF-FM pulses averaging 6-6 milliseconds, with up to three harmonics. Second harmonic is the most intense, starting with a CF component at 55 kHz and ending with a QCF component of ¢.48-7 kHz. Movements, Home range and Social organization. The Big Naked-backed Bat prefers roosting in large and humid cave systems, where it is found in association with other species of mormoopids and phyllostomids. Status and Conservation. Classified as Least Concern on The IUCN Red List. Bibliography. Bernard et al. (2011), Bredt et al. (1999), Cajaiba (2014), Carter & Dolan (1978), Eshelman & Morgan (1985), GBIF Secretariat (2017), Ibanez & Ochoa (1989), Ibanez et al. (2000), Patton & Gardner (2008), Pavan & Marroig (2016, 2017), Rocha et al. (2011), Sbragia & Cardoso (2008), Simmons & Conway (2001), Smith (1972, 1977), Vargas-Mena et al. (2018), Willig (1985a).