Mantidactylus noralottae Mercurio & Andreone, 2007

Scherz, Mark D., Crottini, Angelica, Hutter, Carl R., Hildenbrand, Andrea, Andreone, Franco, Fulgence, Thio Rosin, Köhler, Gunther, Ndriantsoa, Serge Herilala, Ohler, Annemarie, Preick, Michaela, Rakotoarison, Andolalao, Rancilhac, Loïs, Raselimanana, Achille P., Riemann, Jana C., Rödel, Mark-Oliver, Rosa, Gonçalo M., Streicher, Jeffrey W., Vieites, David R., Köhler, Jörn, Hofreiter, Michael, Glaw, Frank & Vences, Miguel, 2022, An inordinate fondness for inconspicuous brown frogs: integration of phylogenomics, archival DNA analysis, morphology, and bioacoustics yields 24 new taxa in the subgenus Brygoomantis (genus Mantidactylus) from Madagascar, Megataxa 7 (2), pp. 113-311 : 217-223

Mantidactylus noralottae Mercurio & Andreone, 2007

Type material.— The species is based on holotype (by original designation) MRSN A5317 from ‘ Ambovo, Parc National de l’Isalo, Fianarantsoa Faritany, Ranohira Fivondronana , 22°30.48′S, 45°21.15′E, 996 m a.s.l. ’. A total of 12 paratypes were defined in the original description: MRSN A5036 ( FAZC 13021 ), MRSN A5035 ( FAZC 13020 ), MRSN A5254 ( FAZC 13008 ), MRSN A5318 ( FAZC 13024 ), SMF 85861 (ex MRSN A5253 / FAZC 13007 ), SMF 85862–85864 (ex MRSN A5255– 5257 / FAZC 13011–13013 ), MRSN A5252 ( FAZC 13005 ), PBZT-FAZC 12996 , PBZT-FAZC 12998 , and ZSM 49/2011 (ex MRSN A5319 / FAZC 13022 ) , all with the same locality, date and collector as the holotype.

Identity.—This species is genetically defined by the sequences of various paratypes published in the original description (MRSN A5252 and A5254; SMF 85861‒SMF 85864 corresponding to previous MRSN A5253 and A5255‒A5257; Mercurio & Andreone 2007). Unfortunately, no genetic data are available for the holotype or the call voucher paratype, MRSN A5317. However, both the holotype and the call voucher are comparatively large-sized individuals of 34.8 and 33.4 mm SVL, respectively, and thus distinctly larger than the second species of the M. betsileanus clade occurring at Isalo (described below as M. riparius sp. nov.). Furthermore, according to measurements in Mercurio & Andreone (2007) and here reproduced in Table 7, the male holotype of M. noralottae has a smaller relative tympanum size and smaller femoral glands than the third species of Brygoomantis at Isalo, M. mahery (see above and Tables 4‒5 ), confirming the holotype of M. noralottae is conspecific with the paratypes and other individuals usually assigned to this taxon.

Diagnosis.—A member of the M. betsileanus clade as revealed by the phylogenomic analysis, sister to M. kortei sp. nov. described below. See Table 4 for a list of diagnostic morphological characters. The combination of a moderate body size in males (SVL 33–36 mm) and distinctly larger size in females (SVL 36–40 mm), rather smooth to slightly tubercular dorsal skin with distinct continuous dorsolateral ridges, relatively large tympanum (10–12% of SVL), absence of white spots on flanks, absence of a white marking on snout tip, and advertisement call consisting of a single, long note composed of ≥90 pulses distinguishes M. noralottae from species of all other clades ( Table 4 ); M. noralottae may appear superficially similar to some species of the M. curtus clade but these have a smaller tympanum and less pulses in advertisement calls. Within the M. betsileanus clade, the species differs from all species except M. betsileanus (for M. incognitus sp. nov. calls are unknown) by a higher number of pulses in advertisement calls ( Table 4 ); it differs from these two species by larger body size of males, and from M. betsileanus also by fewer pulses in advertisement calls ( Table 4 ). For a detailed distinction from its sister species M. kortei sp. nov., from the sympatric M. riparius sp. nov., and from all other new species described herein, see the respective species accounts. A full list of molecular diagnostic sites in the 16S gene of M. noralottae in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.

Variation.—Variation in measurements is given in Table 7. See Fig. 36 for colouration in life and its variation. A light vertebral line can be present. There is moderate sexual size dimorphism (confirmed male SVL 32.8–35.5 mm [n = 4] vs confirmed female SVL 35.5– 40.0 mm [n = 7]). Tympanum size is somewhat larger in males compared to females (HTD/ED ratio is 56–63% in females, 63–95% in males). Femoral glands in males are not very prominent and not conspicuously coloured.

Natural history.—According to Mercurio and Andreone (2007) the species inhabits canyons in the Isalo limestone massif, and can be found from the initial openings all the way to their deep end (eg. Anjofo waterfall). Individuals can climb on rocks and cling at 150– 200 cm height above the water or the ground. Mercurio and Andreone (2007) also provide some information on stomach content, according to which the species feeds on different groups of insects. Although the species cooccurs with M. noralottae at Isalo, the two species have so far not been found in the same streams or at exactly the same sites in this massif.

Calls.—The advertisement call of M. noralottae , recorded on 18 December 2004, 20:00 h, at Ambovo, Isalo National Park, 20°C air temperature (from paratype MRSN A5319), consisted of a very long, regularly pulsed note ( Fig. 37 ), emitted in irregular series. Each note showed some significant amplitude modulation with call energy slowly increasing to approximately the middle of the note’s duration and then slowly decreasing towards its end. Numerical parameters of five analysed calls were as follows: call duration (= note duration) 2054–2705 ms (2411.4 ± 273.9 ms); ca 92–108 pulses per note (100.6 ± 7.1); pulse duration 9–15 ms (10.9 ± 1.6 ms); pulse repetition rate within notes 37.4–41.2 pulses/s (39.7 ± 1.3); dominant frequency 1345–1405 Hz (1370 ± 26 Hz); prevalent bandwidth 1200–2100 Hz; call repetition rate (= note repetition rate) ca 12 calls/min.

Tadpoles.— The tadpole of this species has not been described.

Distribution.— Apparently microendemic to the Isalo massif ( Fig. 7 ). Elevation range: 640–996 m a.s.l.

Etymology.—Eponym for Nora Lotta Mercurio née Fr̂hder, wife of V. Mercurio, one of the authors of the original description.

Figures

FIGURE 7. Mantidactylus subgenus Brygoomantis species distribution based on verified records, divided by clade (Mantidactylus stelliger sp. nov. is presented alongside the inaudax clade for practicality). Colours for species correspond to those in Figs 2 and 4. Inset map shows the geographic regions of Madagascar identified by Boumans et al. (2007), referred to throughout the text.

FIGURE 36. Mantidactylus noralottae from the Isalo massif in life, in dorsolateral and ventral view. (a,b) Adult female (tissue ACZC 7948; FAZC 14340). (c,d) Adult male (tissue ACZC 7947; FAZC 14339).

FIGURE 37. Audiospectrogram and corresponding oscillogram of a 1000 ms section of one advertisement call (call duration 2704 ms) of Mantidactylus noralottae, recorded 18 December 2004 at Ambovo, Isalo National Park (20°C air temperature). Recording bandpass-filtered at 1000–3500 Hz.