Gephyromantis matsilo sp. nov. (lineage A)

Vences, Miguel, Koehler, Joern, Crottini, Angelica, Hofreiter, Michael, Hutter, Carl R., du Preez, Louis, Preick, Michaela, Rakotoarison, Andolalao, Rancilhac, Lois, Raselimanana, Achille P., Rosa, Goncalo M., Scherz, Mark D. & Glaw, Frank, 2022, An integrative taxonomic revision and redefinition of Gephyromantis (Laurentomantis) malagasius based on archival DNA analysis reveals four new mantellid frog species from Madagascar, Vertebrate Zoology 72, pp. 271-309 : 271

Gephyromantis matsilo sp. nov. (lineage A)

Holotype.

ZSM 711/2009 (field number ZCMV 7234), adult male, from campsite "Ambatoroma, S II " (a campsite in the Manompana - Befanjana Forest area, approximately at coordinates 16.66°S, 49.59°E; precise elevation unknown), Analanjirofo Region, eastern Madagascar, collected on 19 May 2009 by J.E. Randrianirina.

Paratypes.

ZSM 712/2009 (ZCMV 7300), adult female, from campsite "Babitanety, S III" (Manompana - Befanjana Forest), Analanjirofo Region, eastern Madagascar, collected on 20 May 2009 by J.E. Randrianirina; MRSN A5678 (FAZC 13344), adult male, from Sahavontsira (Miorimivalana, Fenerive Est), Analanjirofo Region, eastern Madagascar, collected on 23 January 2006 by F. Andreone, F. Mattioli and J.E. Randrianirina; ZMA 20247 (ZCMV 90), adult male, from Ambohitsara (21.3572°S, 047.8157°E, 294 m a.s.l.), Vatovavy-Fitovinany Region, eastern Madagascar, collected on 21 January 2004 by D.R. Vieites and I. de la Riva.

Etymology.

The species epithet is derived from the Malagasy adjective Gephyromantis matsilo (spiny) and refers to the spiny tubercles on the dorsum of this frog. The name is used as a noun in apposition.

Diagnosis.

A member of the subfamily Mantellinae based on the presence of intercalary elements between terminal and subterminal phalanges of fingers and toes (verified externally), and on the absence of nuptial pads and presence of femoral glands in males. Assigned to the subgenus Gephyromantis Laurentomantis in the genus Gephyromantis based on the strongly tubercular dorsal skin, absence of foot webbing, completely connected lateral metatarsalia, and molecular phylogenetic relationships. The new species differs from all nominal species of the subgenus Gephyromantis Laurentomantis as follows: From G. horridus by smaller body size (male SVL 21.7-21.9 mm vs. 33.5 mm) and absence of a dorsal pattern of two blackish transverse patches (vs. presence); from G. ranjomavo by slightly smaller body size (male SVL 21.7-21.9 mm vs. 23.5-28.1 mm), absence of light brown to orange-brown color covering limbs dorsally (vs. presence), and absence of a tibial gland (vs. presence); from G. striatus by absence of a vertebral stripe posteriorly on dorsum (vs. presence) and a more strongly tubercular dorsal skin; from G. malagasius (as redefined herein) by absence of a distinct bluish gray pattern on a dark venter (vs. presence); and from G. marokoroko by a more coarsely tubercular dorsal skin, presence of red color ventrally on limbs (vs. absence), absence of orange spots and vermiculations on dorsum (vs. presence), and absence of gray to whitish color on vocal sac (vs. presence). Also distinguished from G. horridus and G. striatus by longer notes in advertisement calls (13-21 vs. 3-12 ms). Furthermore, from all nominal Laurentomantis species distinguished by the presence of bright red color in the inguinal region and probably ventrally on limbs and posterior belly in life (see. Fig. 17 where this color is recognizable in the inguinal region) (vs. absence), and by a substantial genetic divergence (>8% uncorrected pairwise distance in the 16S gene). For a distinction from the other new species described in the following (lineages B, C and D), see the diagnoses in the respective species accounts below.

Description of the holotype.

Adult male in good state of preservation (Fig. 18 ). SVL 21.9 mm, for other measurements see Table 1 . Body slender; head slightly longer than wide, wider than body; snout rounded in dorsal and lateral views; nostrils directed laterally, distinctly protuberant, much nearer to tip of snout than to eye; canthus rostralis concave; loreal region distinctly concave; tympanum distinct, rounded, 77% of eye diameter; no supratympanic fold except some elevated skin folds directly encircling the tympanum dorsally; tongue ovoid, distinctly forked posteriorly; vomerine teeth absent; choanae rounded; maxillary teeth present. Dermal fold along the posterior part of the lower jaws (the inflatable parts of the vocal sac) weakly expressed. Arms slender, subarticular tubercles single; outer and inner metacarpal tubercles weakly expressed, not prominent; fingers without webbing; relative length of fingers 1 <2 = ≤ 4 <3, second finger distinctly shorter than fourth finger on right hand, almost of same length on left hand; finger discs enlarged; nuptial pads absent. Hindlimbs slender; tibiotarsal articulation reaching nostrils when hindlimb is adpressed along body; lateral metatarsalia connected; inner metatarsal tubercle distinct, outer metatarsal tubercle small but recognizable; webbing between fingers and toes absent; relative toe length 1 <2 <5 = 3 <4. Third toe of same length as fifth toe. Toe discs enlarged. Skin on upper surface granular, with rather indistinct ridges especially on anterior dorsum, and many smaller irregularly distributed tubercles on head, eyes, and dorsum. Ventral skin smooth on throat, chest and limbs, slightly granular on posterior belly. Femoral glands well delimited and distinctly recognizable from external view. No tibial glands.

After twelve years in preservative, dorsal coloration of head and body uniformly dark brown, with darker crossbands on hind- and forelimbs. Posterodorsal surface of thigh with a small pigmentless patch near the knee joint, this area presumably corresponding to reddish color in life. Ventrally cream, with a rather faint and irregular brown marbling, which is more contrasted on the ventral surface of the hindlimbs.

Variation.

All photographed and examined specimens of G. matsilo lack a tibial gland. The male ZMA 20247 from Ambohitsara agrees with the morphology of the specimens examined from the northern localities in the Befanjana forest, including body size, and a more spiny-granular dorsal skin compared to specimens of lineage B. The female ZSM 712/2009 is distinctly larger than the two measured males (SVL 24.9 mm vs. 21.7-21.9 mm).

Call.

The advertisement call (Fig. 19 ) was recorded on 12 December 2007 at Vohitsivalana, RNI Betampona (air temperature 20°C; Rosa et al. 2011: track 24; sequence HM364637 from specimen FAZC 13977). It consists of a series of short distinctly pulsed notes. There is considerable amplidude modulation within each call, with call energy being greatest at approximately the middle of the call, with initial notes being the least energetic. Within calls, notes are repeated at very constant intervals. Each note contains several clearly separated pulses repeated at an approximate rate of 500 pulses/second. In some notes, the terminal pulse is separated by a slightly larger interval from preceding pulses. Numerical parameters of 14 analyzed calls are as follows (range followed by mean ± standard deviation in parentheses): call duration 355-660 ms (552.3 ± 88.0 ms); note duration 13-21 ms (16.2 ± 2.5 ms); number of notes per call 8-15 (12.6 ± 1.9); note repetition rate within calls 20.8-21.6 notes/second (21.2 ± 0.3 notes/second); pulses per note 6-10 (6.9 ± 1.1); dominant frequency 3090-3434 Hz (3200 ± 116 Hz); prevalent bandwidth 2000-4700 Hz. Calls were emitted more or less isolated or in short call series (containing up to 12 calls) at a rate of 24-31 calls/minute within series.

Distribution and natural history.

Based on genetically verified records, the distribution area spans a south-north direction from: (1) Ambohitsara to (2) Betampona, (3) Ambodiriana, (4) two sites in Befanjana, and (5) Sahavontsira. The known elevational range of the species spans from near sea level (Ambodiriana, 53 m a.s.l.) to approximately 294 m a.s.l. (Ambohitsara). Very little is known on the natural history of this species. Despite intensive sampling, only three individuals of this species have been collected at Betampona, where the most commonly found Laurentomantis species is the lineage D. All individuals were collected in rainforest habitat.

Figures

Figure 17. Specimens of Gephyromantis matsilo sp. nov. (lineage A) in life in dorsolateral view. A Specimen from Ambodiriana probably corresponding to tissue sample PSG 1015. B Specimen from Antanambe, probably corresponding to tissue sample PSG 49. Vouchers not collected (photo by P. S. Gehring).

Figure 18. Preserved holotype specimens of the four new Gephyromantis species in dorsal and ventral view. A, B G. matsilo sp. nov. (lineage A), ZSM 711 / 2009 (ZCMV 7234) from Ambatoroma, Befanjana Forest. C, D G. fiharimpe sp. nov. (lineage B), ZSM 164 / 2016 (FGZC 5181) from Mandraka. E, F G. oelkrugi sp. nov., ZSM 314 / 2010 (FGZC 4220) from Ambodivoangy. G, H G. portonae sp. nov. (lineage D), ZSM 115 / 2021 (ACZCV 0032) from Betampona.

Figure 19. Audiospectrogram and corresponding oscillogram of one advertisement call of Gephyromantis matsilo sp. nov. recorded on 12 December 2007 at Betampona. The oscillogram below shows a 100 ms section of the call figured above, showing two notes and their respective pulse structure.