Bioacoustics of Mantidactylus kortei

Identity and justification .—This lineage has only been found at high elevations of the Andohahela Massif, in a swamp and along streams. In previous DNA barcoding assessments, it has been considered as M. sp. 30 by Vieites et al. (2009) and M. sp. Ca30 by Perl et al. (2014) . It is sister to M. noralottae from Isalo in the phylogenomic analysis (but according to 16S data may also be closely related to M. riparius sp. nov. which is not represented in the phylogenomic analysis; see below). However, it differs from M. noralottae in advertisement call and morphology (e.g. smaller body size; Table 4 ), and from its two siblings by a high genetic divergence (≥4.3% from M. noralottae , and ≥5.9% from M. riparius sp. nov. ), supporting its species status. Some individuals of M. kortei sp. nov. are characterized by a relatively short snout, but this is apparently not the case in all individuals.

Calls. —The advertisement call of M. kortei , recorded on 27 January2005 atAndohahela National Park (specimens not seen calling, therefore attribution of calls not completely certain, but very likely), 17.6°C air temperature ( Vences et al. 2006 : CD2, track 78), consists of a pulsed note ( Fig. 45 ), emitted in series at irregular intervals and slow succession. Notes exhibited slight amplitude modulation, with maximum call energy occurring either during the first third of the note’s length or at the centre of the note, and the terminal pulse of the note always containing the lowest energy. In some calls, initial pulses were separated by longer inter-pulse intervals, whereas the 3-5 terminal pulses of all calls are narrowly spaced and have very short interpulse intervals. Numerical parameters of nine analysed calls, corresponding to at least two different individuals, are as follows: call duration (= note duration) 254–511 ms (356.9 ± 94.5 ms); 12–27 pulses per note (18.9 ± 4.6); pulse duration 3–6 ms (4.4 ± 0.8 ms); pulse repetition rate within notes (excluding narrowly spaced terminal pulses) 29.0–69.0 pulses/s (47.9 ± 10.1); dominant frequency 1123–1399 Hz (1224 ± 124 Hz); prevalent bandwidth 750–3200 Hz; call repetition rate (= note repetition rate) ca 4–11 calls/min. Tadpoles.— The tadpole of this species has not been described.

Diagnosis .— Mantidactylus kortei sp.nov. is a member of the M. betsileanus clade and related to M. noralottae in the phylogenomic analysis. See Table 4 for a list of diagnostic morphological characters. The combination of a relatively small body size (male SVL 27 mm ), slightly tubercular dorsal skin with distinct continuous dorsolateral ridges, relatively large tympanum (13% of SVL in males), presence of a white marking on the snout tip in most specimens, and advertisement call consisting of a single pulsed note not repeated in regular series distinguishes M. kortei sp. nov. from species of all other clades. Species of the M. fergusoni clade are larger and have typically a more tubercular dorsum, while species of the M. curtus clade are often larger and most have a smaller tympanum. Some specimens of the new species have whitish dots on the flanks and only an indistinct white marking on the snout tip, which impedes their distinction from some species of the M. biporus , M. stelliger and M. inaudax clades where advertisement calls are unknown. However, the usually more pointed snout, larger tympanum, longer limbs, and overall different appearance of M. kortei sp. nov. should make a distinction straightforward ( Table 4 ). Within the M. betsileanus clade, the new species can be distinguished from M. betsileanus , M. noralottae and M. tripunctatus by having fewer pulses per note in advertisement calls; furthermore from M. noralottae by smaller body size. Mantidactylus katae has a different advertisement call structure and larger femoral glands; M. jonasi has typically more pulses per note in advertisement calls, a slower pulse repetition rate, and a more tubercular dorsum; and M. incognitus has more expressed dorsal and dorsolateral ridges and supraocular tubercles ( Table 4 ). For a detailed distinction from other new species described herein, see the respective species accounts. A full list of molecular diagnostic sites in the 16S gene of M. kortei sp. nov. in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.