Bioacoustics of Mantidactylus biporus

Calls.— The advertisement call of M. biporus recorded at Betampona on 31 October 2007 at 20:00 h, 19°C air temperature ( Rosa et al. 2011 : track 34), consisted of a short, regularly pulsed note ( Fig. 64 ), emitted in regular series at very fast succession. Slight amplitude modulation was present, with relative amplitude increasing from the beginning of the call, reaching its maximum approximately at the last third of the note’s duration. Calls in call series tended to become louder and longer from the beginning to the end of a series. Numerical parameters of 45 analysed calls of two individuals were as follows: call duration (= note duration) 93–132 ms (109.7 ± 11.2 ms); 15–21 pulses per note (17.4 ± 1.8); pulse duration 4–5 ms (4.7 ± 0.5); pulse repetition rate within notes 130.4–210.5 pulses/s (165.8 ± 27.9); dominant frequency 832–997 Hz (884 ± 61 Hz); prevalent bandwidth 400–3000 Hz; call repetition rate (= note repetition rate) within regular series ca 300–360 calls/min. Call series (n = 4) had a duration of 2290–5875 ms. Tadpoles.— The tadpole of this species has not been described. The tadpole described under this name by Knoll et al. (2007) refers to M. inaudax bona species , see below.

Diagnosis .—A member of the M. biporus clade, sister to the new species M. augustini sp. nov. (described below) according to our phylogenomic analysis. See Table 4 for a list of diagnostic morphological characters. The combination of a moderate body size (male SVL 28- 32 mm , female SVL 31–36 mm [one probably immature female 19.3 mm ]), rather smooth dorsal skin without dorsolateral ridges, moderate to relatively large tympanum size in males (10–12% of SVL), presence of white spots on flanks, absence of a white marking on the snout tip, and a short, pulsed advertisement call emitted in rapid succession in regular series, distinguishes M. biporus from species of the M. betsileanus , M. curtus , M. fergusoni , M. tricinctus , and M. ulcerosus clades. Mantidactylus inaudax ( M. inaudax clade) is morphologically similar but appears to have a larger tympanum in males, and a lower pulse repetition rate in advertisement calls. Mantidactylus biporus is distinguished from its sister species M. augustini sp. nov. by larger body size, smaller tympanum, shorter hindlimbs, less pulses per note and higher pulse rate in advertisement calls. For a distinction from the other (all new) species in the M. biporus , M. stelliger and M. inaudax clades, see the diagnoses in the respective species accounts below. A full list of molecular diagnostic sites in the 16S gene of M. biporus in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.