Bioacoustics of Boophis brachychir

Redescription. Based on specimen CAS 156812 (Appendix 9), adult male, SVL 41.5 mm . Body moderately slender; head longer than wide, slightly wider than body; snout long, rounded in dorsal and lateral view, nostrils directed laterally, nearer to eye than to tip of snout; canthus rostralis sharp in cross section, straight in dorsal view, reaching the tip of snout; loreal region slightly concave; eye large; tympanum distinct, rounded, TD 67% of ED; supratympanic fold thin, clearly distinct; vomerine odontophores distinct, well separated in two elongated patches, positioned posteromedial to choanae; choanae medium-sized, elongated. Tongue posteriorly bifid, free. Arms moderately slender; a pointed dermal appendage on elbow; subarticular tubercles single, round; inner palmar tubercle narrow, elongated, in close contact with nuptial pad; fingers moderately webbed and with lateral dermal fringes; webbing formula 1(1.5), 2i(1.5), 2e(0.75), 3i(2), 3e(1.5), 4(1); relative length of fingers 1<2<4<3 (finger 2 distinctly shorter than finger 4); finger discs enlarged. Hind limbs slender; a pointed dermal appendage on heel; tibiotarsal articulation reaching tip of snout when hind limb is adpressed along body; lateral metatarsalia separated by webbing; inner metatarsal tubercle small, distinct, elongated; no outer metatarsal tubercle; toes broadly webbed; webbing formula 1(0), 2i(0.25), 2e(0), 3i(0.75), 3e(0), 4i(0.75), 4e(0.75), 5(0.25); relative length of toes 1<2<3<5<4; toe discs enlarged. Skin smooth on dorsal surfaces, finely granular on throat and chest, coarsely granular on belly, granular on ventral surface of thighs. Measurements (in mm): SVL 41.5, HW 14.3, HL 16.4, ED 5.8, END 3.4, NSD 3.3, NND 4.2, TD 3.9, TL 23.1, HAL 12.4, FOL 18.3, FOTL 30.5. In preservative, ground colour of upper surface of head, dorsum and legs pale brown with darker, irregular, diffuse markings and some dark brown small blotches; legs barred; flanks pale beige; a fine cream stripe on upper lip. Almost no reticulated pattern on posterior surface of thighs and no whitish subocular bar recognizable. Ventral surfaces creamy beige. Colour in life unknown. Variation. Morphological variation is given in Appendix 2. The background colouration of dorsal surfaces is always brown, but the pattern varies from mostly uniform to a pattern consisting of small, scattered grey (in preservative) lichenous blotches (ZSM 933/2003, male) or irregular blackish blotches (ZSM 586/ 2001). Specimens ZSM 897/2003, ZSM 2156/2007 (FGZC 1219), juveniles, and ZSM 2157/2007 (FGZC 1220), female, have a pinkish grey (in preservative) triangle between eyes and snout and two dorsolateral bands of the same colour connected on the sacral region; they also have an oblique, white subocular bar. The supratympanic fold is bordered inferiorly by a dark brown stripe in some specimens. No remarkable variation exists in ventral pattern. Calling specimens were not observed in detail during call emission but as far as recognizable upon capture had a single subgular vocal sac. Referred specimens. ZSM 993 /2003, Camp Norbert , Manongarivo , 5 February 2003 , collected by F. Glaw , R . D. Randrianiaina and M. Vences ; ZSM 2155 /2007, 2156/2007, 2227/2007, 2228/2007 (males) , ZSM 2157 /2007, 2230/2007 (females), Forêt d'Ambre Special Reserve , 12°28'00'' S , 49°13'37'' E , 470 m a.s.l. , collected on 12 March 2007 by P. Bora, F. Glaw and J. Köhler. Natural history. At Manongarivo, calling specimens were observed at perch heights of about 2 m in bushes in a largely cleared and degraded area near rainforest, at a distance of at least 15 m from a larger fastflowing stream with alternating rocky and sandy bottom. At Forêt d'Ambre, non-calling specimens were observed at night in the vegetation of a degraded forest, at perches 0.5–2 m above the ground. Vocalization. The call of B. brachychir from Manongarivo Special Reserve is a long series of short whistles, repeated in very fast succession ( Fig. 9 ). Notes are separated by very short intervals only. Overall amplitude as well as note repetition rate is increasing towards the end of the call. Each note shows some amplitude modulation, with a distinct energy peak at its end. The call ends with two "noisy" pulsatile notes which may also be emitted separately. Numerical call parameters are as follows: call duration, 4015 ms (n = 1); 45 notes/ call; note duration, 50–78 ms (62 ± 9; n = 26); inter-note interval, 20–30 ms (24 ± 2; n = 26); note repetition rate, 10.7–13.0 notes/second. Dominant frequency range 2400–3100 Hz, maximum call energy at 2610–2720 Hz. Pulsatile notes may be of slightly longer duration, 68–94 ms (n = 5), and their call energy is distributed in a slightly wider frequency band (1500–3400 Hz). These pulsatile notes are emitted at irregular intervals ( Vences et al. 2006 , CD 1, track 62, as Boophis sp. aff. brachychir ).