Mantidactylus tripunctatus Angel, 1930

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 : 223-224

Mantidactylus tripunctatus Angel, 1930 bona species

Type material.— Mantidactylus tripunctatus Angel, 1930 is based on syntypes: MNHN 1931.21 , 1931.23–25 and MCZ 14280 [formerly MNHN 1931.22 ] ( Barbour & Loveridge 1946; Guibé 1978), from ‘ Pic St. Louis , province de Fort-Dauphin’ and ‘ Befotaka , province de Farafangana ... à l’altitude de 700 mètres, au bord d’un torrent, en forêt’. We here designate MNHN 1931.24 , probably a subadult/ juvenile specimen from Pic St. Louis , as lectotype because we could obtain genetic data from this specimen . Lectotype designation is justified by the need to stabilize this and other nomina in Brygoomantis , given the uncertain identity and morphological similarity of many taxa in the subgenus.

Identity.—This nomen has been considered a nomen dubium by Guibé (1978), Blommers-Schl̂sser and Blanc (1991) and Glaw and Vences (1992a), and as a junior synonym of M. betsileanus by Frost (2021). Using barcode fishing we obtained a 16S sequence of the lectotype which firmly clusters among sequences of a lineage morphologically similar to M. betsileanus that is widespread and common in the Tolagnaro (= Fort Dauphin) area, including the environments of the Pic St. Louis, and considered as M. sp. 29 or M. sp. Ca29 by Vieites et al. (2009) and Perl et al. (2014), and depicted as ‘ Mantidactylus sp. aff. betsileanus “Tolagnaro”’ by Glaw andVences(2007).In the phylogenomic tree, a specimen of M. tripunctatus is placed in a subclade with M. noralottae and two other new species described below as M. katae sp. nov. and M. kortei sp. nov., and relationships between these species are also supported by the 16S tree; all of the species differ from each other in their advertisement calls, and M. noralottae also is characterized by larger body size ( Table 4 ), confirming their species-level distinctness and justifying elevation of M. tricinctus to species status.

Diagnosis.—A member of the M. betsileanus clade as revealed by the phylogenomic analysis, probably sister to M. katae sp. nov. described below (but see below for uncertainties regarding the samples of M. katae included in the phylogenomic analysis). See Table 4 for a list of diagnostic morphological characters. The combination of a relatively small body size in males (SVL 26–27 mm) and distinctly larger size in females (SVL 33–35 mm), slightly tubercular dorsal skin with distinct continuous dorsolateral ridges, reduced webbing (one phalanx of fifth toe free of web), absence of white spots on flanks, presence of a white marking on snout tip, and advertisement call consisting of a single, long note composed of ≥70 pulses distinguishes M. tripunctatus from species of all other clades ( Table 4 ). Within the M. betsileanus clade, the species differs from M. betsileanus by a lower number of pulses in advertisement calls and a lower pulse repetition rate; and from M. noralottae by smaller body size and presence of a distinct white marking on snout tip ( Table 4 ). For a distinction from the new species described herein, see the respective species accounts. A full list of molecular diagnostic sites in the 16S gene of M. tripunctatus in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.

Variation.—Variation in measurements is given in Table 7. See Fig. 38 for colouration in life and its variation.

A light vertebral line can be present. There is pronounced sexual size dimorphism (confirmed male SVL 26.4–27.0 mm [n = 3] vs confirmed female SVL 32.9–34.7 mm [n = 5]). Tympanum size is quite variable but does not seem to differ consistently and strongly between sexes (HTD/ED ratio is 53–93% in females, 93–95% in males).

Natural history.—At the base of Pic St. Louis (Tolagnaro) we observed calling males at night, sitting at the edge of shallow puddles in a small, very slowly running stream surrounded by remains of rainforest.

Calls.—Advertisement calls of individuals probably belonging to M. tripunctatus (but not DNA barcoded), recorded in February 1991 at a site near Tolagnaro, air temperature unknown ( Vences et al. 2006: CD2, track 68, cut 1), consists of a long, regularly pulsed note ( Fig. 39 ), emitted in series. The available recording was of relatively poor quality and partly suffered from the overlap of calls of different individuals, making it difficult to assess and measure all parameters precisely. Numerical parameters of five analysed calls were as follows: call duration (= note duration) 1380–1870 ms (1612.8 ± 197.8 ms); ca 70–80 pulses per note (estimate according to overlap of calls); pulse duration 11–19 ms (14.2 ± 2.6 ms); pulse repetition rate within notes 41.7–47.6 pulses/s (45.6 ± 2.3); dominant frequency 1383–1556 Hz (1460 ± 75 Hz); prevalent bandwidth 1200–3400 Hz; call repetition rate (= note repetition rate) ca 8–9 calls/min.

Calls recorded on 1 January 1992 at Pic St. Louis near Tolagnaro, 23°C air temperature ( Vences et al. 2006: CD2, track 68, cuts 2 & 3), generally agree in character with the other calls from Tolagnaro described above. Although difficult to evaluate due to overlapping calls of multiple individuals, call duration seems to be longer, roughly ranging from 2100–2600 ms. Pulse repetition rate in these calls is slightly lower and ranges from ca 30–39 pulses/s.

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

Distribution.— Apparently microendemic to a small area in far South East of Madagascar ( Fig. 7 ). This species is known from Andohahela, Manantantely, Mandena, Nahampoana, Pic St. Louis, and Tsitongambarika. Elevation range: 8–415 m a.s.l.

Etymology.—Latin adjective meaning ‘having three spots’, presumably in reference to some feature of the colouration.

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 38. Specimens assigned to Mantidactylus tripunctatus in life, in dorsolateral view. (a) Probably adult male (based on large tympanum size) from Pic St Louis near Tolagnaro, photographed in 1991. (b) Probably adult male (based on large tympanum size) from Nahampoana, photographed in 1991.

FIGURE 39. Audiospectrogram and corresponding oscillogram of a 1000 ms section of one advertisement call (call duration 1545 ms) of Mantidactylus tripunctatus, recorded February 1991 near Tolagnaro. Recording bandpass-filtered at 1200–4100 Hz.