Guibemantis razoky, Koppetsch & Pabijan & Hutter & Köhler & Gehring & Rakotoarison & Ratsoavina & Scherz & Vieites & Glaw & Vences, 2023

Koppetsch, Thore, Pabijan, Maciej, Hutter, Carl R., Koehler, Joern, Gehring, Philip-Sebastian, Rakotoarison, Andolalao, Ratsoavina, Fanomezana M., Scherz, Mark D., Vieites, David R., Glaw, Frank & Vences, Miguel, 2023, An initial molecular resolution of the mantellid frogs of the Guibemantis liber complex reveals three new species from northern Madagascar, Vertebrate Zoology 73, pp. 397-432 : 397

Guibemantis razoky sp. nov.

Figs 9 , 12 , 13

Holotype.

ZSM 1746/2010 (field number ZCMV 12515), adult male, collected in Bemanevika 'Camp 1' (Antsira-kala; 14.43061°S, 48.60179°E, 1466 m a.s.l.), Sofia Region, northern Madagascar on 27 June 2010 by M. Vences, D. Vieites, R.D. Randrianiaina, F. Ratsoavina, S. Rasamison, A. Rakotoarison, E. Rajeriarison and T. Rajoafiarison.

Paratypes.

A total of 27 specimens: ZSM 1744-1745/2010, 1747-1750/2010, 1837/2010, 540-543/2014 (field numbers ZCMV 12513, 12514, 12516, 12523, 12531, 12532, 12539; DRV 6339-6341, 6366), adults and subadults, with same collection data as holotype; ZSM 1751-1753/2010 (field numbers ZCMV 12558, 12574, 12591), two males and one female, collected near Bemanevika River (14.48251°S, 48.62723°E, 1109 m a.s.l.) on 29 June 2010 by M. Vences, D. Vieites, R.D. Randrianiaina, F. Ratsoavina, S. Rasamison, A. Rakotoarison, E. Rajeriarison and T. Rajoafiarison; ZSM 70-73/2016 (field numbers MSZC 0036, 0070, 0144, 0157), four adult males collected from a Pandanus swamp at Ampotsidy (14.41694°S, 48.71449°E, 1371 m a.s.l.) on 6 January 2016 by M.D. Scherz, J. Borrell, L. Ball, T. Starnes, E. Razafimandimby, D.H. Nomenjanahary and J. Rabearivony; ZSM 74-75/2016 (field numbers MSZC 204, 240), two adult males collected at Andranonafindra forest (30 km SW of Bealanana on the RN31; 14.73600°S, 48.54831°E, 1180 m a.s.l.) on 14 January 2016, by M.D. Scherz and M. Rakotondratisma; ZSM 877-878/2003 (field numbers FGMV 2002.874, 2002.875), two adult males collected on Montagne d’Ambre (precise coordinates not taken) on 17 February 2003 by F. Glaw, R.D. Randrianiaina and A. Razafimanantsoa; ZSM 890-892/2003 (field numbers FGMV 2002.898, 2002.899, 2002.900), two males and one female, collected at Montagne d’Ambre, Voie des mille arbres (approximately at coordinates 12.520°S, 49.176°E, 1052 m a.s.l.) on 18 February 2003 by F. Glaw, R.D. Randrianiaina and A. Razafimanantsoa; ZSM 120/2018 (field number MSZC 712), an adult male, collected on Montagne d’Ambre (near Lac Maudit: 12.58528°S, 49.15094°E, 1249 m a.s.l.) on 1 December 2017 by M.D. Scherz, J.H. Razafindraibe, A. Razafimanantsoa, O. Randriamalala, S.M. Rasolonjavato, R.T. Rakotonindrina and A. Rakotoarison; ZSM 119/2018 (field number MSZC 520), an adult male collected on Montagne d’Ambre (12.51994°S, 49.17274°E, 1044 m a.s.l.) on 25 December 2017 by M.D. Scherz, J.H. Razafindraibe, A. Razafimanantsoa, O. Randriamalala, S.M. Rasolonjavato, R.T. Rakotonindrina and A. Rakotoarison.

Diagnosis.

This species corresponds to the mitochondrial lineages NOR+NCENTR as defined herein. It is assigned to the subgenus Guibemantis Pandanusicola of the genus Guibemantis based on presence of intercalary elements between ultimate and penultimate phalanges of fingers and toes (verified by external examination), moderate to weakly expressed webbing between toes, connected lateral metatarsalia, the presence of both inner and outer metatarsal tubercles, femoral glands in males, absence of nuptial pads, moderately small body size (SVL 26.5-33.9 mm in males and 29.8-32.8 mm in females), and molecular phylogenetic relationships. Within Pandanusicola , the new species is distinguished from all species except G. liber , G. razandry , and G. tasifotsy by femoral glands type 1 (vs. type 2) as defined by Glaw et al. (2000), thus possessing many small gland granules in a relatively diffuse field covering most of the thigh ventrally, and by its probable breeding in open swamps (vs. phytotelmic breeding in Pandanus leaf axils). It can be distinguished from G. tasifotsy by its different brownish color pattern lacking a green dorsal and lateral coloration with series of distinct white blotches along the lower flanks, and its different advertisement call, namely a short click-like note of 20-117 ms duration and 2598-3010 Hz dominant frequency (vs. a longer trill-like note of 147-516 ms duration and higher dominant frequency; Lehtinen et al. 2012). The new species differs from all G. liber lineages occurring in the Northern and Southern Central East of Madagascar by its high DNA divergence> 2.4% in the mitochondrial 16S gene, by a larger SVL, and differences in the advertisement call. It differs from G. razandry (described above) by larger SVL, different advertisement call, and a molecular 16S divergence>5.5%. It also differs from G. liber and G. razandry by 3 and 41 diagnostic positions in the analyzed fragment of the cytochrome b gene, respectively (see Appendix 2 for a list of diagnostic sites). For a distinction from the third new species described herein, see below.

Description of holotype.

Adult male in good state of preservation (Fig. 9 ). A small piece of muscle tissue from right thigh removed for molecular analysis. Ventral skin cut open and bladder removed for parasite examination. SVL 28.0 mm. For full morphometric measurements see Table 1 . Body relatively slender; head slightly longer than wide, wider than body; snout rounded in dorsal, ventral, and lateral views; nostrils much nearer to tip of snout than to eye, slightly protuberant and pointed anterolaterally; canthus rostralis distinct, straight; loreal region straight; tympanum distinct, relatively small, its diameter 70% of eye diameter; distinct supratympanic fold; tongue ovoid, strongly bifid posteriorly; posterior tongue extensions slightly serrated; vomerine teeth as one weakly expressed rounded aggregation posterolateral of each choana; choanae small, rounded. Forelimbs slender; subarticular tubercles distinct and single; central metacarpal tubercle large and rounded, outer metacarpal tubercle smaller and oval; a small but indistinct prepollex (which could also be considered as an inner metacarpal tubercle) at base of first finger. Fingers without webbing; relative finger length I<II<IV<III; finger discs distinctly enlarged; nuptial pads absent. Outer toe and finger discs darker than inner toe and finger discs. Hind limbs long and slender; when adpressed along body, the tibiotarsal articulation reaches beyond the eye; lateral metatarsalia connected by tissue; inner metatarsal tubercle distinct, larger than outer; outer metatarsal tubercle distinct; webbing formula of the foot 1(traces), 2i(traces), 2e(1), 3i(2), 3e(1), 4i(2.75), 4e(3), 5(1.25); relative toe length I<II<III = V<IV. Skin dorsally smooth; ventral skin as far as recognizable smooth on throat, chest, slightly granular on belly. Femoral glands recognizable from external view but not very distinct, also in life (Fig. 12 ) not very prominent and of same color as surrounding shank, possibly because the specimen was collected outside of the reproductive season. Glands consisting of many small gland granules in a relatively diffuse field covering most of thigh ventrally, thus of type 1 as defined by Glaw et al. (2000).

After eleven years in preservative (70% EtOH; Fig. 9 ), dorsal background coloration grayish brown with two prominent blackish dorsolateral discontinuous bands consisting of densely arranged blotches and extending posteriorly from eye orbits to hips. Rostral stripe dark brownish. Dorsally, from between orbits a dense field of brown blotches, running over most of dorsum and becoming more scattered on posterior dorsum. Interrupted and indistinct whitish middorsal line. Forelimbs with irregular and partially interrupted dark, brownish bands and spots extending from shoulders to fingers. Outer finger discs darkish brown. Ventrally, throat and forelimbs largely unpigmented (yellowish-brownish in preservative), chest with some fine dark brown dotting, belly more pigmented with dense pattern of brown dots that leave out some larger unpigmented markings, and the hindlimbs dark largely brown. Dorsal surface of thighs and shanks dark reddishbrown with indistinct broad dark blotches and interrupted bands. Like finger discs, some outer toe discs dark reddish brown, of noticeably different color than adjacent tissue.

Based on photographs of the holotype specimen (Fig. 12 ), body coloration in life was pinkish brown. Dorsally and on both forelimbs and hindlimbs, with a chocolate brown pattern, consisting of irregular-sized blotches and spots. Also, supratympanic fold and rostral stripe chocolate brown. Dorsally, from an imaginary line between the orbits to the axilla with a dense field of brown blotches. A yellowish interrupted and indistinct middorsal line. Ventrally, background color pinkish-whitish, but chest, throat and the anterior part of belly bright white. Posteriorly and laterally belly semi-transparent. Ventrolaterally, small white spots in anterior part, larger bright yellow spots posteriorly. First finger and toe intensely yellow. Numerous femoral gland granules visible, but not highlighted in color. Iris (whitish in preservative) copper metallic in life.

Variation.

Specimens in the type series show differences in color pattern. For instance, in preservative two specimens of the NOR lineage, ZSM 890/2003 and ZSM 877/2003, have a distinct light vertebral stripe while ZSM 878/2003 is dorsally more or less uniformly brownish. In the NCENTR lineage, ZSM 1748/2010 has highly contrasted beige markings on a brown dorsum, including one beige patch anterior to the eyes. While ZSM 1837/2010 is, again, mostly uniform brown dorsally, and ZSM 1747/2010 is dorsally primarily beige, with some dark brown spots and incomplete light vertebral stripe laterally bordered by dark brown. Males collected during the breeding season have a distinct bright white throat, which is not obvious in any of the specimens collected at Bemanevika in June, making it difficult to sex them; however, many of these specimens appear to be males based on gonad examination, suggesting that outside of the breeding season males do not have white throats/vocal sacs. There seems to be no obvious sexual size dimorphism as is typical for the G. liber complex. For variation in morphometric features see Table 1 .

Natural history.

In November to December of 2017 we observed numerous congregations of calling males of G. razoky on Montagne d’Ambre. One congregation on the shore of Lac Maudit (ca. 1320 m a.s.l.) consisted of several males and clutches of eggs (Fig. 13F-H ), suggesting that the tadpoles of the species may even enter this large lake. A massive congregation, consisting of dozens of specimens and possibly hundreds of clutches, was found in a temporary swamp at ca. 1000 m a.s.l. (Fig. 13A-D ). Among this congregation were also Blommersia wittei and G. albomaculatus . Clutches of eggs were observed to be predated by wasps and ants (Fig. 13E ). In Ampotsidy, calling individuals and clutches were found in a swamp with large Pandanus plants in December. Outside of the breeding season (in June) we found specimens near Bemanevika River hidden in the leaf axils of Pandanus screw pines, syntopic with Blommersia blommersae , Guibemantis sp. aff. pulcher , and G. razandry . As with apparently most lineages in the G. liber complex, G. razoky occurs both in areas of primary rainforest and in highly degraded and fragmented forest patches, e.g., near Bemanevika.

Vocalization.

Advertisement calls recorded on 14 March 1994 at Montagne d’Ambre National Park (air temperature 21.2°C) consists of a single, click-like note of rather variable duration containing a low number of well-separated pulses (Fig. 17 ). Calls (= notes) are usually emitted in short series at rather regular intervals. Numerical parameters of 24 analyzed calls are as follows: call duration (= note duration) 20-117 ms (52.7 ± 29.3 ms); number of pulses per call 2-4 (2.6 ± 0.7); dominant frequency 2598-3010 Hz (2731 ± 120 Hz), with two weaker additional energy peaks at approximately 5400 and 8100 Hz; prevalent bandwidth 2000-8600 Hz. Within call series (containing 3-10 calls; maximum duration of call series 1773 ms), call rate varied from 270-330 calls/minute.

Distribution.

Since many Pandanusicola species appear to be phenotypically similar and are therefore often taxonomically confused, we restrict our assessment of distribution to populations for which molecular data are available. According to our data, G. razoky appears to be a regional endemic of northern Madagascar, and is so far reliably known from six localities (not taking into account the imprecise site "Bealanana region": (1) Bemanevika, the type locality; (2) Ampotsidy; (3) Andranonafrindra forest; (3) Tsaratanana; (4) Makira; (5) Montagne d’Ambre (where a genetically distinct mitochondrial lineage occurs). These localities are from elevations between 1044 and 1466 m a.s.l. Furthermore, genetic samples assigned to this species based on mitochondrial DNA exist from the low-elevation site Ambodiriana (about 50 m a.s.l.) but no voucher specimens from this site are available, and this record thus requires confirmation.

Etymology.

The name is derived from the Malagasy word Guibemantis razoky meaning larger (elder) sibling, and refers to the fact that this species is the larger-sized relative of the syntopic G. razandry . The name is used as a noun in apposition to the genus name.

Figures

Figure 9. Preserved name-bearing holotype specimens of Guibemantis razandry sp. nov. (ZSM 293 / 2005) (A, B), Guibemantis razoky sp. nov. (ZSM 1746 / 2010) (C, D), and Guibemantis fotsitenda sp. nov. (ZSM 292 / 2005) (E, F) in dorsal and ventral view.

Figure 12. Specimens of Guibemantis razoky sp. nov. in life, in dorsal and ventral views. A, B Male holotype ZSM 1746 / 2010 (field number ZCMV 12515) from Bemanevika. C, D Female paratypes ZSM 1744 / 2010 (field number ZCMV 12513), and E, F ZSM 1745 / 2010 (field number ZCMV 12514) from Bemanevika. G, H Male paratype from Montagne d'Ambre (ZSM 878 / 2003) (shown in Lehtinen et al. 2012 as G. liber).

Figure 13. Breeding assemblages of Guibemantis razoky sp. nov. on Montagne d'Ambre. A - E Scenes from a single locality where dozens of specimens and hundreds of clutches were found, alongside individuals of Blommersia wittei and Guibemantis albomaculatus. Red circles are G. razoky sp. nov. individuals, blue circles are clutches. E Ants swarming eggs on a Pandanus frond. F Lac Maudit (~ 1320 m a. s. l.) at sunset. G Guibemantis razoky sp. nov., and H a clutch of their eggs from the bank of Lac Maudit.

Figure 17. Audiospectrogram and corresponding oscillogram of a series of advertisement calls (3 calls) of Guibemantis razandry sp. nov. recorded on 16 February 2005 at Marojejy National Park. Recording band-pass filtered at 1000 - 9500 Hz.