Bioacoustics of Laephotis robertsi

Description. External characters. A moderately large Neoromicia with a tail less than 40% of total length (Table 3). The three specimens of N . robertsi comprising the type series (UADBA 43677, 43678, FMNH 213931) have notably shaggy dark chocolate drown dorsums and ventrums, longer than, slightly darker, and more saturated than typical N . matroka . The ventrum fur of N . robertsi , particularly the outer fur of the upper portion of the chest, often has a slightly lighter sheen, which gives the impression of being bi-colored and in N . matroka these accents are not present. The surfaces of the patagium and uropatgium are a distinct blackish-brown, similar to N . matroka and N . malagasyensis . The ear length in the holotype of N . robertsi is 13 mm , which is the same measurement as in the two paratypes (Table 3), and in general falls within the range of N . matroka and N . malagasyensis . The dorsal surface of the pinna of N . robertsi , particularly the lower proximal half is furred, which is distinctly less developed in N . malagasyensis and mostly naked in N . matroka . Neoromicia robertsi has notably dark blackish-brown pinna and tragus, the later representing less than 50% of the length of the former. The main body of the tragus in N . robertsi has the two outer margins running mostly in parallel for approximately two-thirds of the proximal length and then turns medially, curves slightly, and terminates with a rounded margin ( Figure 5 A). Further, there is a distinct notch at the base of the tragus along the posterior border. In comparison, N . matroka has a tragus length about 60% that of the ear length, the crescent-shaped tragus terminates as a rounded sickle-shape, and the notch at the posterior base of the structure is less developed than in N . robertsi ( Figure 5 B). In N . malagasyensis the tragus length represents between 50-65% the ear length, the tragus is slightly more crescent-shaped than in N . robertsi , but not as prominent as in N . matroka , and lacks a distinct notch at the base along the posterior border ( Figure 5 C). On the basis of external measurements of the type series of N . robertsi , this species seems to show sexual dimorphism in size, with the single female specimen being notably larger than the two males in total length, tail length, and forearm length. The two males have an average forearm length of 34.5 mm and the female measures 38 mm , as compared to 31.9 mm and 33.9 mm , respectively, in N . matroka from the Central Highlands (OTU 1, Table 3). On average, based on two specimens, N . malagasyensis is smaller than the other two Malagasy members of this genus. Cranio-dental characters. Dental formula in Neoromicia robertsi , as in other members of the genus, is I 2 /3 C 1/1 P 1/3 M 2/3, comprising the adult dentition of 32 teeth. Neoromicia robertsi is easily distinguished from other Malagasy members of this genus based on its notably larger cranial measurements (Table 4). Of the two skulls available of this taxon (both males), the greatest skull length of UADBA 43677 ( holotype ) is 14.3 mm and FMNH 213931 is 14.6 mm . These measurements are larger and do not overlap with the average greatest skull length of N . matroka from the Central Highlands (OTU 1) of 12.9 mm and in N . malagasyensis of 12.8 mm . Further, with the exception of postorbital width, the different cranial measurements of N . robertsi are larger and non-overlapping with those of N . matroka and N . malagasyensis . In N . robertsi , the supraorbital ridge is notably more inflated than N . matroka and N . malagasyensis . Neoromicia robertsi is easily distinguished from other Malagasy Neoromicia based on its notably larger upper and lower dental measurements (Table 5). Of the two skulls available of this taxon (both males), the length of the complete cranial tooth row of UADBA 43677 ( holotype ) and FMNH 213931 are both 6.0 mm. These values are notably larger and do not overlap with the average length of the complete cranial tooth row of male N . matroka from the Central Highlands (OTU 1) of 5.1 mm and in N . malagasyensis of 4.7 mm . The upper tooth rows in N . robertsi are largely in parallel, while in N . matroka and N . malagasyensis are more of an arc shape and converge anteriorly. In N . robertsi , the 2nd upper incisor, which is approximately one-half the height of the 1st upper incisor, has a distinct single cusp on the posterior margin, as compared to N . matroka , which has a more complicated bicuspid 2nd incisor ( Figures 6 A and 6B). The incisors in N . malagasyensis are distinctly different with the 2nd upper incisor without a distinct secondary cusp and the 1st upper incisor being about two-thirds the length of 2nd ( Figure 6 C). Further, in N . capensis , including the holotype (BMNH 97.9.1.32), the 2nd upper incisor is a peg-like tooth with no clear secondary structure ( Figure 6 D). The diastema between the 2nd upper incisor and the upper canine is most prominent in N . robertsi as compared to the other Malagasy members of this genus. Male baculum characters. The baculum of N . robertsi is typical of the genus Neoromicia , with strong ventral deflection of the tip, but diagnostically larger than any described species. Natural history, distribution, and conservation status. Neoromicia robertsi is only known from two localities in central eastern Madagascar , where it occurs in sympatry with N . matroka ( Figure 1 ). The specimens of N . robertsi from the Parc National de Mantadia were obtained at an elevation between 900 and 1000 m , and the holotype from Anjozorobe, between 1200 and 1300 m. These two sites are both associated with partially degraded habitats, one of which is in close proximity to a forested zone. Hence, N . robertsi does not appear to be a forest restricted species, but has not been found roosting in a synanthropic context, which is known for N . matroka (Goodman 2011) . No precise details are known about the reproductive ecology of N . robertsi . The pair obtained on 8 November 2002 at Mantadia (UADBA 43678, FMNH 213931) included a male with relatively large testes and, based on the form and shape of the mammae, a female that recently gave birth and lactated. The holotype (UADBA 43677) was an adult male. Bioacoustic information of animals that can be definitively identified as N . robertsi is not available. Kofoky et al. (2009) made recordings of hand-released individuals of Neoromicia at Mantadia and Anjozorobe, sites N . matroka and N . robertsi are known to occur, and based on the forearm length of released individuals it is not possible to determine which species was involved. Neoromicia at these sites had an average frequency of maximum energy of 41.5 kHz (range 39.2-44.3 kHz); average maximum frequency of 69.2 kHz (range 60.3-88.2 kHz); average minimum frequency of 37.7 kHz (range 35.5-39.3 kHz); average duration of 5.7 ms (range 3.8-8.0 ms); and average interpulse interval of 109.9 ms (range 65.2-196.7 ms), as compared to N . malagasyensis near Isalo where these values were 45.7 kHz (range 41.4-51.0 kHz), 79.8 kHz (range 60.3-100.0 kHz), 40.5 kHz (range 32.4-45.5 kHz), 4.9 ms (range 3.6-6.3 ms), and 34.2 ms (range 34.2-94.4 ms), respectively. Thus, while it is not apparent if differences exist between N . matroka and N . robertsi in bioacoustic parameters, N . malagasyensis shows some divergent aspects in their echolocation calls. An older mummified specimen (MNHN 1882.1964) was obtained by Jean Auguste Lantz in the “interieur de Madagascar C. est, mai 1881 ” at a locality that cannot be properly read from the specimen label but appears to be “Ambohiramiane”. The skull still remains in the specimen, but based on the coloration of the notably long pelage, the partially furred proximal portions of the upper surface of the ears, and a forearm length of 34 mm , it may be referable to N . robertsi . In total, we have examined over 60 specimens of N . matroka , as compared to three specimens of N . robertsi . The disproportional number of specimens of the former species may be in part associated with its broader distribution and use of buildings for day roost sites, providing easier access to field collectors. However, based on current information, N . robertsi has a limited distribution and appears notably less common than N . matroka . Further, information is needed to assess its distribution and population size, in order to properly evaluate its conservation status.