Phoniscus atrox Miller, 1905

Thong, Vu Dinh, Bumrungsri, Sara, Harrison, David L., Pearch, Malcolm J., Helgen, Kristofer M. & Bates, Paul J. J., 2006, New records of Microchiroptera (Rhinolophidae and Kerivoulinae) from Vietnam and Thailand, Acta Chiropterologica 8 (1), pp. 83-93 : 89-90

Phoniscus atrox Miller, 1905

Groove-toothed trumpet-eared bat

Phoniscus atrox Miller, 1905: 230 ; Vicinity of the Kateman River, eastern Sumatra

New material, previous records and distri- bution

Thailand: Wildlife Research Station, Bala Forest, Hala-Bala Wildlife Sanctu- ary, Wang District, Narathiwat Province

(05°48’N, 101°50’E), 21 May 2003, 1 ♂ (PSU-M 05.11) collected by S. Bumrungsri.

In Thailand, the previous locality record is Klong Bang Sai, Patiyu District, Chum- phon Province (10°43’N, 99°20’E — Kloss, 1916). It is also known from peninsular Malaysia, Sumatra and Borneo (Simmons, 2005) and possibly Lao PDR (Francis et al., 1999).

Description and taxonomic notes

In general, the pelage of P. atrox is comparable to that of P. jagorii but slightly paler. Kloss (1916) noted that of his two Thai specimens, the female was duller and darker than the male. With a forearm length of 34.3 mm (Table 1), the current specimen slightly exceeds in size those (32.3, 32.6 mm) listed in Hill (1965). However, the condylobasal length of 14.0 mm (Table 2) is within the range (0 = 13.6, 13.1–14.1 mm, n = 7) of specimens of P. atrox in The Natural History Museum, London. The mor- phology of the skull is similar to that of P. jagorii , except that the basioccipital pits are shallower (see above). In the dentition, the upper canine is very large, with its outer side having two deep grooves. The upper

premolars are significantly smaller than those of P. jagorii ( Fig. 3 ). This is evident in the first (P2) and especially the second (P3) premolar. Furthermore, in comparison to P. jagorii , P3 is essentially round in out- line, rather than rectangular, and without an antero-internal elongation. The second lower premolar (P3) is particularly narrow ( Fig. 3 ).

Echolocation

Based on recent material from Thailand, like P. jagorii , the echolocation calls of P. atrox are characterized by broad FM sweeps. The initial frequency (0 ± SD) is 125.53 ± 7.31 kHz (n = 6) and the terminal frequency is 61.80 ± 3.76 kHz. The mean peak frequency is 77.37 ± 6.55 kHz (range 64.6–83.5). Generally, energy is distributed fairly evenly throughout the emitted call. The calls have low intensity and a relative- ly short duration of 2.97 ± 0.79 ms. Occa- sionally, calls are emitted in series with an interval of 14–18 ms. In Malaysia, King- ston et al. (1999) reported a start frequency of 166.1 kHz (145.6–183.2, n = 42), an end frequency of 60.0 kHz (51.2– 72.0, n = 42), a peak frequency of 86.9 kHz (62.4–122.4, n = 42), and a call duration of 2.8 ms (1.9–3.9, n = 42).

Ecological notes and conservation status

In Bala Forest, Thailand, a single indi- vidual was captured in the early evening (19:00 hrs) in disturbed forest interspersed with orchards and rubber plantations. This area, at an elevation of 150 m a.s.l., is adja- cent to a large patch of pristine lowland evergreen forest. Phoniscus atrox appears to favour birds’ nests, particularly those of the broad bill ( Eurylaimus sp.) as a diurnal roost. In eastern Sumatra, the holotype and paratype, both females, were collected on 9th September, 19:03 hrs from an aban- doned nest of a broad bill in dense forest on the banks of the Kateman River. Individuals belonging to this species were also captured in birds’ nests in Malaysia (T. Kingston, personal comm.). The first record from Ma- laysia was of a subadult collected at 615 m a.s.l. from the Ulu Gombak Forest Reserve, Selangor (Medway, 1969). The first record from Thailand was an adult male and fe- male caught in January, 1916 ( Kloss, 1916). Its conservation status is lower risk, least concern (Hutson et al., 2001).

Figures

FIG. 3. Left maxillary (above) and mandibular (below) toothrows of P. jagorii, XS.53 (left), P. atrox, PSU-M 05.11 (centre), and K. kachinensis, CMR-28 (right). (i): I3, much reduced in Phoniscus; (ii): antero-internal elongation of P3 in P. jagorii; (iii): P3 larger and rectangular in P. jagorii in comparison to P. atrox; (iv): P3 narrow in Phoniscus, broader in Kerivoula. Scale = 2 mm