Mantidactylus marintsoai, 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 : 250-253

Mantidactylus marintsoai sp. nov.

Identity and justification.—This lineage was newly identified in this study. It consists of frogs from the North East of Madagascar that form a mitochondrially homogeneous lineage that probably is the sister group of M. georgei ( Fig. 2 ; M. marintsoai sp. nov. is not included in the phylogenomic tree), with which it shares a unique Rag-1 haplotype ( Fig. 4 ). Despite the lack of unambiguous morphological differences to M. georgei and the absence of bioacoustic data for M. marintsoai sp. nov., we here name this lineage as new species, given its enormous genetic divergence (7.6–9.3% uncorrected 16S distance to M. georgei ).

Holotype.— CURSA-A 0033/2021 (field number THC301), adult male, collected by T.R. Fulgence, D.A. Martin, R. Randriamanantena, R. Botra, E. Befidimanana, A. Wurz, K. Osen, H. Kreft, A. Andrianarimisa, and F. M. Ratsoavina on 30 August 2018 in the eastern part of Marojejy National Park ‘Bangoabe’ (14.4467°S, 049.8251°E, ca 225 m a.s.l.), Sava Region, Madagascar. A 16S barcode sequence of the holotype was obtained in this study and was included in the analysis.

Paratypes.—A total of six paratypes: CURSA-A 0034/2021 (THC248, THC245, THC246), three adult females, collected by T.R. Fulgence, D.A. Martin, R. Randriamanantena, R. Botra, E. Befidimanana, A. Wurz, K. Osen, H. Kreft, A. Andrianarimisa, and F. M. Ratsoavina on 18 January 2018 in a stream of Fokontany Andramanolotra/Sambava (13.9953°S, 050.0711°E, ca 54 m a.s.l.); CURSA-A 0036/2021 (THC354), adult female, and THC355, juvenile, collected by the same team on 22 November 2018 in the same location; CURSA –A 0035/2021 (THC233) adult female, collected by T.R. Fulgence, D.A. Martin, R. Randriamanantena, R. Botra, E. Befidimanana, A. Wurz, K. Osen, H. Kreft, A. Andrianarimisa, and F. M. Ratsoavina on 3 February 2018 in a stream in the Antsirabe-Nord / Vohemar, Fokontany of Bemanevika (13.9864°S, 049.9519°E, ca 61 m a.s.l.) .

Diagnosis.— Mantidacytlus marintsoai sp. nov. is a member of the M. fergusoni clade, and is probably the sister lineage of M. georgei , according to the 16S tree (it is not included in the phylogenomic analysis). See Table 4 for a list of diagnostic morphological characters. The combination of a moderate to large body size (male SVL 29 mm, female SVL 35–39 mm), moderately tubercular dorsal skin, relatively large tympanum size in males (13% of SVL), absence of white spots on flanks, and absence of a white marking on the snout tip, distinguishes M. marintsoai sp. nov. from most species of the other clades ( Table 4 ). Two species from the M. ulcerosus clade ( M. ulcerosus and M. bellyi ) can be morphologically similar; these two species occur in the Sambirano and North West regions, and the distribution area especially of M. bellyi may overlap with that of M. marintsoai sp. nov. which is known from the North East; a distinction may be possible by the apparently more strongly developed foot webbing in M. bellyi and M. ulcerosus ( Table 4 ). Mantidactylus marintsoai sp. nov. shows similarities to species of the M. betsileanus clade but does not appear to occur sympatrically with any of them; in general, it has a more tubercular dorsum and seems to lack a distinct white marking on the snout tip which characterizes many species of the M. betsileanus clade ( Table 4 ). Within the M. fergusoni clade, a bioacoustic comparison is not possible due to the lack of call data for M. marintsoai sp. nov.; the species might be distinguished from M. fergusoni , M. georgei and M. jahnarum by less developed foot webbing ( Table 4 ), and seems to differ from many specimens of M. georgei and M. jahnarum by the lack of a clear white marking on snout tip. For a 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. marintsoai sp. nov. in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.

Description of the holotype.— Adult male in good state of preservation ( Fig. 48 ). For measurements, see Table 8. Body rather stout. Head longer than wide. Snout rather pointed. Nostrils directed laterally, slightly protuberant, nearer to tip of snout than to eye. Canthus rostralis distinct, loreal region slightly concave. Tympanum distinct, large, round, horizontal diameter of tympanum 97% of horizontal eye diameter. Supratympanic fold distinct, beginning straight above, with rather distinct bend midway towards insertion of forelimb. Tongue ovoid, distinctly bifid posteriorly.Vomerine teeth form two elongate aggregations, positioned posterolateral to choanae. Choanae rounded.

Subarticular tubercles single. Outer metacarpal tubercle not recognisable, inner metacarpal tubercle present. Fingers without webbing. Relative length of fingers: I<II<IV<III.

Finger discs slightly enlarged. Nuptial pads absent. Foot slightly shorter than tibia (98%). Lateral metatarsalia separated. Inner metatarsal tubercle present. Outer metatarsal tubercle not recognisable. Webbing formula: 1(1), 2i(1), 2e(0.5), 3i(2), 3e(1), 4i(2), 4e(2), 5(1). Relative length of toes: I<II<V<III<IV. Skin on the upper surface smooth, dorsolaterally smooth. Ventral side smooth. Femoral glands small and distinct in external view.

Colour in preservative: dorsally brown, with two distinct light spots. Forelimbs light brown with 2–3 dark brown crossbands on hand and arm. Hindlimbs light brown with distinct dark brown crossbands. Inguinal region with few scattered whitish spots. Snout tip with a light spot (width 1.1 mm, height 1.2 mm), tympanum region slightly lighter than remaining head sides. Venter beige with light brown mottling, throat darker than belly with brown mottling. Lower lip with distinct alternating light and brown spots. Toe discs dark brown.

Variation.—Variation in measurements is given in Table 8. See Fig. 55 for colouration in life and its variation. Some individuals have mid-dorsal stripes ( Fig. 55b ). There may be pronounced sexual size dimorphism, but sample sizes are small (confirmed male SVL 29.0 mm [n = 1] vs confirmed female SVL 34.6–38.7 mm [n = 5]). Males seem to have a larger tympanum than females (HTD/ED ratio is 103% in the only known male, 50–71% in females). Femoral glands in life, in the only known male, are relatively small and indistinct, and not conspicuously coloured; tiny rudimentary glands are recognisable in females.

Natural history.—Found in rainforest patches of the North East of Madagascar. All individuals were found in or near streams in rainforest, including degraded primary forest, secondary forest, and narrow riparian forest fragments. In 2019, the riparian forest beside the village of Bemanevika was felled.

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

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

Distribution.— Apparently endemic to a rather small area of the North East of Madagascar ( Fig. 7 ).

This species is known from Marojejy, Andramanolotra, and Bemanevika village (a Fokontany of AntsirabeNord, in the Vohemar district). Elevation range: 16–273 m a.s.l.

Etymology.—T.R. Fulgence wishes to dedicate this species to his father, the late Marintsoa, in recognition of his support of his son’s scientific career and pursuit of a PhD degree. The name is used as a noun in apposition.

Figures

FIGURE 2. Maximum Likelihood tree of 1305 sequences of a fragment of the 16S rRNA gene (alignment length 519 bp) from a RAxML analysis. Numbers at nodes are bootstrap proportions in percent (100 ML fast bootstrap replicates); not shown if <50%. A sequence of Mantidactylus melanopleura was used as the outgroup (removed from the tree after analysis for better graphical representation). Note that some of the ‘Museomics’ sequences (obtained by targeted capture from historical type specimens) are represented twice, after assembly with different reference sequences. Some sequences in the analysis (several ‘Museomics’ sequences as well as others obtained from Illumina sequencing) only partially covered the fragment analysed (226 sequences <300 bp). We emphasize that this tree is based on a single short mitochondrial marker and therefore is unlikely to represent the deep relationships among lineages correctly; for such relationships, refer to the phylogenomic tree (Fig. 5).

FIGURE 4. Network based on sequences of the nuclear-encoded Rag-1 gene (alignment length 351 bp) from 265 specimens of Brygoomantis. The network was built from phased alleles, i.e. each sample is represented twice. The size of circles is proportional to the number of sequences with the same allele. Small black dots represent hypothetical haplotypes (not sampled or extinct) separating sampled haplotypes, when they differ by more than one mutational step.

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 48. Preserved holotype specimens of newly named species in the Mantidactylus fergusoni clade. Scale bars equal 5 mm.

FIGURE 55. Mantidactylus marintsoai sp. nov. in life, in dorsolateral, dorsal and ventral view. (a) Unsexed adult (tissue THT 204, not collected). (b,c) Adult female (THT282, not collected). (d,e) Adult female (CURSA-A036/2021 = THC354). (f,g) Adult male (holotype CURSA-A033/2021 = THC301).