Mantidactylus brevirostris, Scherz & Crottini & Hutter & Hildenbrand & Andreone & Fulgence & Köhler & Ndriantsoa & Ohler & Preick & Rakotoarison & Rancilhac & Raselimanana & Riemann & Rödel & Rosa & Streicher & Vieites & Köhler & Hofreiter & Glaw & Vences, 2022

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 : 273-275

Mantidactylus brevirostris sp. nov.

Identity and justification.—A deep genetic lineage of the M. biporus clade known from Betampona, and Sahavontsira. This lineage has been considered as unconfirmed candidate species M. sp. 31 by Vieites et al. (2009) and M. sp. Ca31 by Perl et al. (2014). It was referred to as ‘ M. sp. aff. biporus [Ca FJ559260 ]’ by Rosa et al. (2012). According to the phylogenomic analysis, it represents the sister taxon of another lineage named below ( M. eulenbergeri sp. nov.) but differs from that lineage by a 16S distance of 8.6–9.1%, and possibly by at least one morphological difference in foot webbing, suggesting a status as distinct species.

Diagnosis.— Mantidactylus brevirostris sp. nov. is a member of the M. biporus clade, sister to the new species M. eulenbergeri sp. nov. (described below) according to our phylogenomic analysis. See Table 4 for a list of diagnostic morphological characters. The combination of a small body size (male SVL 23 mm, female SVL 28 mm), rather smooth dorsal skin without dorsolateral ridges, large tympanum size in males (12% of SVL), presence of white spots on flanks, and absence of a white marking on the snout tip, distinguishes M. brevirostris sp. nov. from species of the M. betsileanus , M. curtus , M. fergusoni , M. tricinctus , and M. ulcerosus clades. The distantly related M. inaudax ( M. inaudax clade) is morphologically very similar but appears to reach larger body sizes, has more developed foot webbing, and has in many individuals a pattern where the colour of flanks differs from that on the dorsum; M. biporus occurs syntopically with M. brevirostris sp. nov. but has a larger body size and a more developed foot webbing; M. augustini has longer hindlimbs and a more developed foot webbing; M. bletzae has a more granular dorsal skin with dorsolateral ridges and a more developed foot webbing ( Table 4 ). For a distinction from the other 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. brevirostris sp. nov. in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.

Holotype.— MRSN A6257 ( FAZC 13581 ), adult male, collected by G.M. Rosa, and F. Andreone on 9 February 2007 at Sahambendrana, Réserve Naturelle Intégrale de Betampona (17.8984°S, 049.2154°E, 458 m a.s.l.), Antsinanana Region, Madagascar. A 16S barcode sequence of the holotype is available from GenBank (accession HM364736 ).

Paratypes.—A single paratype: ZSM 185/2021 ( ACZCV 265 , extraction ACP 2211 ; tissue ACZC 6309 ), adult female, collected by A. Crottini, D. Salvi, E. Scanarini, George, J. N̂el, and F. Andreone on 22 November 2013 at Betampona ( Sahabefoza ).

Description of the holotype.—Adult male in good state of preservation ( Fig. 62 ). Fourth and fifth finger from right foot missing (taken as tissue sample). Body rather stout. Head as wide as body. Snout rounded in dorsal view, somewhat truncate in lateral view. Nostrils directed laterally, not protuberant, nearer to tip of snout than to eye.

Canthus rostralis weakly recognisable, slightly concave; loreal region slightly concave. Tympanum distinct, large, as wide as high, horizontal diameter of tympanum 89% of horizontal eye diameter. Supratympanic fold not clearly recognisable, basically corresponding to outer edge of tympanum. Tongue ovoid, bifid posteriorly. Maxillary teeth present. Vomerine teeth form two somewhat elongate aggregations, positioned posterolateral to choanae.

Choanae rounded. Subarticular tubercles single. Inner and outer metacarpal tubercles present. Fingers without webbing. Relative length of fingers: I<II<IV<III. Finger discs slightly enlarged. Nuptial pads absent. Foot very slightly longer than tibia (103%). Lateral metatarsalia separated. Inner metatarsal tubercle present. Outer metatarsal tubercle small but recognisable. Webbing formula: 1(1), 2i(1.5), 2e(1), 3i(2.25), 3e(2), 4i(2.5), 4e(2.5), 5(1.5). Relative length of toes: I<II<V<III<IV.

Skin on the upper surface smooth, without recognisable dorsolateral ridges. Ventral side smooth. Femoral glands small but distinct in external view.

Colour in preservative: dorsally brown, with small dark brown speckles arranged irregularly to give an appearance of three large broad patches of darker colour interrupted by lighter areas. A broad beige vertebral stripe is present and is interrupted in the middle of the dorsum, probably representing a colouration anomaly. Some white spots on the upper jaw and underneath the eye. Two to three relatively distinct dark crossbands on hindlimbs.Ventrally beige, with sparse dark pigmentation on throat, and an alternating light-dark pattern ventrally on lower lip. Colour in life unknown.

Variation.—Variation in measurements is given in Table 10. See Fig. 68 for colouration in life and its variation. Too few specimens have been sexed to assess the degree of sexual size dimorphism. Femoral glands in life are not documented (no photographs of the ventral side available).

Natural history.—Species usually observed in slowrunning parts of streams and other small courses. Active both day and night. Quite shy and able to hide under the mud or actively swimming when disturbed.

Calls.— The call of this species has not been recorded.

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

Distribution.— Endemic to low-elevation (<500 m a.s.l.) rainforest in the Northern Central East ( Fig. 7 ). It is currently known from Betampona and Sahavontsira. Elevation range: 190–517 m a.s.l.

Etymology. — The species epithet is a Latin thirddeclension two-termination adjective, derived from the adjective ‘brevis’, meaning short, and ‘rostrum’, meaning snout, in the genitive singular, and refers to the short snout observed in several individuals of this species.

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 62. Preserved holotype specimens of newly named species in the Mantidactylus biporus clade and of the M. stelliger clade. Scale bars equal 5 mm.

FIGURE 68. Mantidactylus brevirostris sp. nov. from Betampona in life, in dorsolateral view. (a) Unsexed individual (ACP5444 = Bet76). (b) Unsexed individual (ACP5463 = Bet101). (c) Unsexed individual (ACP5463 = Bet68). (d) Unsexed individual (ACP5467 = Bet91).