Mantidactylus eulenbergeri, 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 : 275-276

Mantidactylus eulenbergeri sp. nov.

Identity and justification.—This lineage is a member of the M. biporus clade and has been considered as confirmed candidate species M. sp. 23 by Vieites et al. (2009), and M. sp. Ca23 by Perl et al. (2014). It was depicted as ‘ Mantidactylus sp. aff. biporus “Andasibe”’ by Glaw and Vences (2007). It shows a rather distinctive morphology with a very short snout in at least some specimens, and differs from other lineages of the M. biporus clade by concordant divergence in 16S and Rag-1.According to the phylogenomic analysis, it represents the sister taxon of M. brevirostris but differs from that lineage by a 16S distance of 8.6–9.1%, and possibly by a difference in foot webbing ( Table 4 ). We consider the available evidence sufficient to assign a status of separate species to this lineage.

Holotype.— ZSM 85/2002 (field number MV 2001.1092), adult male, collected by M. Vences on 23–25 November 2001 at Andasibe (18.9333°S, 048.4167°E, 915 m a.s.l.), Alaotra-Mangoro Region , Madagascar. 16S and cox1 barcode sequences of the holotype are available from GenBank (accessions AY848239 and JN133224 ).

Paratypes.—A total of seven paratypes: ZSM 84/2002 ( MV 2001.1090 ), adult female, with same collection data as the holotype; ZSM 919/2003 ( FGMV 2002.949 ), putative female, collected by G. Aprea and collaborators on 20 February 2003 in Vohidrazana ; ZSM 198/2021 ( FAZC 15509, extraction ACP 3664, tissue ACZC 8596), ZSM 199/2021 ( FAZC 15516, ACP 3671, ACZC 8603), MRSN A7047 ( FAZC 15517, ACP 3672, ACZC 8604), MRSN A7048 ( FAZC 15549, ACP 3702, ACZC 8636), MRSN A7049 ( FAZC 15540, ACP 3693, ACZC 8627), all collected in January 2017 at Maromizaha (18.9713°S, 048.4642°E) by E. Coppola .

Additional material.—The following specimens (without genetic data) are tentatively assigned to this species: ZFMK 52674–52675 , collected by F. Glaw and M. Vences in February 1991 and ZFMK 62214 collected by F. Glaw on 1 February 1996 (all from Andasibe ).

Diagnosis.— Mantidactylus eulenbergeri sp. nov. is a member of the M. biporus clade, sister to M. brevirostris according to our phylogenomic analysis. See Table 4 for a list of diagnostic morphological characters. The combination of small body size (male SVL 20–23 mm, female SVL 25–28 mm), smooth dorsal skin with weakly expressed dorsolateral ridges sometimes recognisable, large tympanum size in males (12–14% of SVL), presence of (sometimes only few) white spots on flanks, and absence of a white marking on the snout tip, distinguishes M. eulenbergeri sp. nov. from species of the M. betsileanus , M. curtus , M. fergusoni , M. tricinctus , and M. ulcerosus clades.

M. inaudax ( M. inaudax clade) is morphologically similar but differs by larger body size; M. biporus has a larger body size; M. augustini has longer hindlimbs; M. bletzae has a more granular dorsal skin with dorsolateral ridges; M. brevirostris has a less developed foot webbing ( Table 4 ).

For a distinction from 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. eulenbergeri sp. nov. in pairwise comparisons to all other Brygoomantis species is provided as Supplementary appendix.

Description of the holotype. —Adult male in moderate state of preservation ( Fig. 62 ). Tissue sample removed from right thigh. Body stout. Head as wide as body. Snout very short and rounded in dorsal and lateral views. Nostrils directed laterally, slightly protuberant. Nostrils nearer to tip of the snout than to eye. Canthus rostralis weak, slightly concave. Loreal region weakly concave. Tympanum distinct, large, rounded, diameter 91% of eye diameter.

Supratympanic fold indistinct, following exactly the outline of the large tympanum. Tongue ovoid, distinctly posteriorly bifid. Maxillary teeth present. Vomerine teeth present in two rounded aggregations, positioned posterolateral to choanae. Choanae rounded. Subarticular tubercles single.

Outer metacarpal tubercle recognisable, inner metacarpal tubercle present. Fingers without webbing. Relative length of fingers: I<II<IV<III. Finger discs slightly enlarged.

Nuptial pads absent. Foot longer than tibia (114%). Lateral metatarsalia separated. Inner metatarsal tubercle present.

Outer metatarsal tubercle not present. Webbing formula: 1(1), 2i(1.5), 2e(1), 3i(2), 3e(1), 4i(2.5), 4e(2.5), 5(1).

Relative length of toes: I<II<V<III<IV. Skin on the upper surface smooth. Ventral side smooth. Femoral glands distinct, consisting mainly of a distal ulcerous macrogland recognisable in external view, while only a very small proximal granular gland field is recognisable in external view. Skin on the back is smooth.

Colour in preservative: dorsum brown, with distinct irregular darker markings. A dark brown band between eyes present. Forelimbs brown with distinct darker markings. Hindlimbs brown with distinct darker crossbands. Inguinal region without whitish spots. Snout tip without a light dot. Venter beige, throat darker than belly. Lower lip with distinct alternating light and brown spots. Toe discs dark. Toes light and dark striped. Colour in life as in preservative but more vibrant ( Fig. 69 ).

Variation.—Variation in measurements is given in Table 10. There is pronounced sexual size dimorphism (confirmed male SVL 20.0– 23.3 mm [n = 6] vs confirmed female SVL25.0–28.0mm [n = 4]). Horizontal tympanum diameter is 73–86% of eye diameter in males and 60–78% of eye diameter in females. Skin on the back is smooth. Colour on the back brown with few indistinct markings (e.g. ZSM 84/2002). Few white spots on the flanks are always present. Two dark spots on the back at level of forelimb insertion are present only in ZSM 84/2002. A light interrupted vertebral line is present in ZFMK 62214, ending on the snout tip with a distinct white dot. A light vertebral band is never present. A dark brown and more or less triangular band between eyes is always present. Lower lip with more (e.g. ZSM 85/2002) or less (e.g. ZSM 84/2002) distinct alternating light and brown spots. Venter and throat uniformly beige, in ZFMK 62214 with little white spots. A longitudinal white median line on thorax and throat is present in ZFMK 62214 and very faintly in ZSM 84/2002. Forelimbs brown with irregular darker markings and stripes. Femoral glands of adult males are large and prominent with one indistinct spot on the femoral gland as a small side structure proximal to the cloaca in ZSM 85/2002, with two distinct spots in ZFMK 62214. In females femoral glands are small but can be recognised (e.g. ZSM 84/2002), with two gland rudiments of the same size on each shank.

Natural history.—A species found along small and shallow running water bodies in rainforest.

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

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

Distribution.— Endemic to the Northern Central East ( Fig. 7 ). This species is known from Anivorano Est, Sahafina, Andasibe, Maromizaha, and Vohidrazana. Elevation range: 60–1100 m a.s.l.

Etymology.—We dedicate this species to Klaus Eulenberger, former chief veterinary of Leipzig Zoo, in recognition of his contributions to knowledge on husbandry and veterinary care of captive amphibians and reptiles.

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 69. Mantidactylus eulenbergeri sp. nov. in life, in dorsolateral and ventral view. (a,b) Adult male (holotype ZSM 85/2002 = FGMV 2001.1092) from Andasibe.