Rhombophryne mavokely Scherz, Glaw, Petzold, Andreone, Köhler, Raselimanana, Hutter, Belluardo, Rakotoarison, Hofreiter, Vences & Crottini, 2026, sp. nov.

Résumé fourni par la source

Rhombophryne mavokely sp. nov. Figures 2, 5 –9, 26 –29 Informal names. This species was listed as ‘ Rhombophryne sp. Ca 17 ’ by Belluardo et al. (2022), and ‘ Rhombophryne sp. 17 ’ and ‘ CCS “ Sp. 17 ” ’ by Carné and Vieites (2024). Justification of the new species. The new species is placed in a clade containing R. mangabensis, R. savaka, and an undescribed candidate species (R. sp. Ca 16) from the Andapa area for which only genetic data are known. It differs, however, from all nominal species of Rhombophryne by very high genetic divergences: 10.3 % and 10.9 % uncorrected p distance in the 16 S 3 ’ fragment from R. mangabensis and R. savaka, respectively; and> 11 % from all other species (Belluardo et al. 2022). It furthermore differs from R. mangabensis and R. savaka by the presence of reddish-orange colouration on the posterior thigh, and from the syntopic R. savaka by bioacoustic and further morphological characters (see Diagnosis below). In addition, it is phylogenetically sister to the R. mangabensis / R. savaka subclade (Belluardo et al. 2022) and thus cannot be considered conspecific with either of these species. Its status as distinct species is therefore beyond doubt. Holotype. ZSM 521/2016 (MSZC 0269), an adult male (call voucher), collected on 22 November 2016 in low elevation primary rainforest within Marojejy National Park (14.4400°S, 49.7782°E, 402 m a. s. l.), Sava Region, northeastern Madagascar, by M. D. Scherz, J. H. Razafindraibe, and A. Razafimanantsoa (Figs 8, 9, 26 A – C, 28). Paratypes. Three specimens: ZSM 517/2016 (ZCMV 15088), an unsexed adult, collected on the morning of 16 November 2016 at ‘ Camp 0 ’ (ca 14.446°S, ca 49.785°E, ca 310 m a. s. l.), Marojejy National Park, Sava Region, northeastern Madagascar, by M. D. Scherz, M. Vences, A. Rakotoarison, M. C. Bletz, J. H. Razafindraibe, and A. Razafimanantsoa (Fig. 26 D – G); ZSM 518/2016 (MSZC 0310), a juvenile, and UADBA -A- MSZC 0307 (Fig. 26 H – K), an unsexed adult, both collected in the evening of the 26 November 2016 from the same locality as ZSM 517/2016, by M. D. Scherz, J. H. Razafindraibe, A. Razafimanantsoa, and C. R. Hutter. Assignment of specimens. The holotype is used as the reference specimen for this species in 16 S rRNA barcoding (16 S 5 ’ OL 780607; Belluardo et al. 2022). All paratypes conform well with the holotype in morphology, and are from near the type locality. Assignment of specimens ZSM 518/2016, ZSM 517/2016, and UADBA -A- MSZC 0307 is further confirmed by molecular taxonomic identification (Fig. 2). RAG 1 sequence of this species is so far not available. Definition. Within the R. testudo group, this species is most closely related to R. mangabensis, R. savaka, and its possible sister lineage R. sp. Ca 16 based on molecular phylogenetic data (Fig. 2; Belluardo et al. 2022). It is characterised by the possession of the following unique suite of characters: (1) small body size, adult SVL 21.2–21.3 mm; (2) head wider than long (HW / HL 1.60–1.68); (3) moderately small eyes (ED / HL 0.36–0.38); (4) short hindlimbs (HIL / SVL 1.50–1.61); (5) small inner metatarsal tubercle (IMTL / FOL 0.12–0.13); (6) outer metatarsal tubercle absent; (7) second finger distinctly longer than fourth; (8) third toe distinctly longer than fifth; (9) dorsal skin finely granular with a few scattered warts, especially a suprascapular pair outlined in black; (10) absence of chin barbels; (11) absence of pronounced superciliary spines; (12) absence of inguinal ocelli or spots; (13) presence of reddish orange in the inguinal region and on the posterior thigh; (14) unfortified skull without expansion of maxilla or posterior process of angulosplenial; (15) clavicles present, thin, curving; and (16) advertisement call (based on 16 analysed calls by one individual) tonal, with (17) call duration 231–262 ms, (18) inter-call interval 623–808 ms, and (19) dominant frequency 3178–3265 Hz. Rhombophryne mavokely sp. nov. is furthermore distinguished from all other Rhombophryne species analysed by the following robust diagnostic nucleotide combination in the mitochondrial 16 S rRNA gene (positions relative to the full 16 S sequence of Anilany helenae MZ 751042): in 16 S 5 ’, ‘ A’ at site 315, ‘ C’ at site 326, and ‘ T’ at site 331; in 16 S 3 ’, ‘ G’ at site 937, ‘ G’ at site 938, and ‘ A’ at site 956. Diagnosis. Within the genus Rhombophryne, R. mavokely sp. nov. can easily be distinguished from all species except R. ellae, R. ornata, and two other species described below (R. quentini sp. nov. and R. kotrobaratra sp. nov.), by the presence of reddish orange colouration on the posterior thigh. Among these species, it can be distinguished from R. ellae by a more dorsoventrally compressed habitus, smaller body size (SVL 21.2–21.3 mm vs 24.9 mm), wider head (HW / HL 1.60–1.68 vs 1.47), and shorter hindlimbs (HIL / SVL 1.50–1.61 vs 1.71); and from R. ornata by the absence of superciliary spines (vs presence). For distinction from R. quentini sp. nov. and R. kotrobaratra sp. nov., see the descriptions of those species, below. When the orange of the limbs is not visible there is also some resemblance to R. coudreaui and R. maraorao, which however differ by generally larger adult body size (SVL 21.5–28.9 vs 21.2–21.3 mm), much shorter hindlimbs (HIL / SVL 1.10–1.30 vs 1.50–1.61), and presence of chin barbels (vs absence). Rhombophryne mavokely sp. nov. occurs syntopically or in near sympatry with the closely related R. savaka. Aside from colouration, R. mavokely sp. nov. can be distinguished from R. savaka by its rougher dorsal skin with more ridges (vs relatively smooth), and by the longer advertisement call duration (231–262 ms vs 121–142 ms), longer inter-call interval (623–808 ms vs 221–395 ms), and slightly lower dominant frequency (3178–3265 Hz vs 3714–3861 Hz). Description of holotype. A specimen in a good state of preservation (Fig. 8). A tissue sample was taken from its left thigh for genetic analysis. Body rotund. Head wider than long (HW / HL 1.68). Eyes quite small (ED / HL 0.36), pupils small, round. Snout rounded in dorsal view, truncate in lateral view. Canthus rostralis distinct, concave. Loreal region concave, oblique. Nostril closer to tip of snout than to eye, slightly protuberant. Tympanum indistinct, round, TDH / ED 0.62. Supratympanic fold indistinct, demarcated at its anterior end by a dark comma-shaped marking. In life it was more distinct, curving from the posterior corner of the eye over the tympanum and towards the insertion of the arm (Fig. 26 A). Superciliary spines absent, but two white dots above each eye. Small granules and ridges distributed over the body in life are largely flat in preservative but mostly still marked by a lighter colouration. Most prominent of these are a pair of markings in the suprascapular region, and a series of three (left) and two (right) bumps along the ilia and in the sacral region. Tongue broad, attached anteriorly, posteriorly free. Maxillary and vomerine teeth present, vomerine teeth present in two curving rows separated at the midline by a small gap. Choanae round, placed laterally in the roof of the mouth. Forelimbs relatively short (FARL / SVL 0.417), fairly slender. Fingers without webbing, all short, relative lengths 1 <4 <2 <3, second finger slightly longer than fourth (Fig. 9). Finger tips not expanded, slightly pointed. Finger subarticular tubercles indistinct, whitish; inner metacarpal tubercle broad and flat, outer metacarpal / palmar tubercle indistinct, greyish. Hind limb thick, tibiotarsal articulation reaching the eye when adpressed anteriorly along the body. TIBL / SVL 0.461. Inner metatarsal tubercle present, oblong, whitish. Outer metatarsal tubercle visible only as a slightly lightened area of the outer metatarsus. Toes not webbed; toes unreduced, toe lengths 1 <2 <5 <3 <4, fifth toe distinctly shorter than third; subarticular tubercles distinct, greyish, rather flat; toe tips slightly enlarged, slightly pointed (

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