Gephyromantis corvus bakilana, Scherz & Rudolph & Rakotondratsima & Ratsoavina & Crottini & Andreone & Glaw & Vences, 2024

Scherz, Mark D., Rudolph, Janina, Rakotondratsima, Marius, Ratsoavina, Fanomezana M., Crottini, Angelica, Andreone, Franco, Glaw, Frank & Vences, Miguel, 2024, Molecular systematics of the subgenus Gephyromantis (Phylacomantis) with description of a new subspecies, Zootaxa 5446 (2), pp. 205-220 : 213-214

Gephyromantis corvus bakilana ssp. nov.

Figs. 5–6

Remark. This lineage was assigned the candidate species number G. sp. Ca31 by Scherz et al. (2017).

Holotype. ZSM 63/2016 (field number MSZC 202), adult male ( Figs. 5–6 ), collected on 14 January 2016 by M.D. Scherz and M. Rakotondratsima at Andranonafindra forest (30 km SW of Bealanana on the RN31), geographical coordinates 14.73654°S, 48.54845°E, 1204 m a.s.l., Sofia Region, northwestern Madagascar.

Paratypes. ZSM 64/2016 (MSZC 227) and UADBA-MSZC 223, two adult females, collected on 16 January 2016 by M.D. Scherz and M. Rakotondratsima at Irogno forest , on the border of the Bealanana District (36 km SW of Bealanana on the RN31), geographical coordinates 14.74999°S, 48.49195 –48.49209 °E, 933–947 m a.s.l., Sofia Region, northwestern Madagascar ; ZSM 505/2009 (DRV 5801), an unsexed adult, collected on 21 June 2009 by M. Vences, D. R. Vieites, F. M. Ratsoavina, R.-D. Randrianiaina, E. Rajeriarison, T. Rajoafiarison, and J. Patton at Sahaovy (camp 0), outside but close to the western border of the Makira Natural Park, geographical coordinates 15.48904°S, 49.07854°E, 603 m a.s.l., Sofia Region , northeastern Madagascar .

Diagnosis. A subspecies of Gephyromantis assigned to the subgenus Phylacomantis based on the combination of presence of intercalary elements between ultimate and penultimate phalanges of fingers and toes (assessed by external examination), absence of nuptial pads, a single patch of well-delimited femoral glands of type 2 (sensu Glaw et al. 2000) in males (no rudiments in females), paired or bilobed blackish subgular vocal sacs in males, tubercular skin without regular dorsolateral ridges, medium body size, outer metatarsalia partly connected by tissue, webbing between toes present, inner and outer metatarsal tubercle present, and molecular phylogenetic affinities.

Within the subgenus Phylacomantis , G. c. bakilana ssp. nov. is distinguished from G. pseudoasper by less expressed yellow-orange coloration ventrally on thighs and on femoral glands (vs. usually distinct yellow-orange color), and less distinct median white stripe on throat (vs. usually distinct stripe); from G. kintana by blackish (vs. whitish) vocal sacs, by blackish (vs. whitish) throat, by a blackish (vs. whitish) belly, more strongly granular dorsal skin (vs. less granular), and lower maximum number of granules in the femoral glands (ca. 45 vs. 96); and from G. atsingy by brownish dorsal coloration with orange-brown elements (vs. light brown-beige with a greenish shading) and a lower maximum number of granules in the femoral glands (ca. 45 vs. 70). Morphologically, the new subspecies does not show any known consistent differences to G. corvus corvus ; one potential difference is lessexpressed dorsal orange-brown color pattern in G. c. corvus , but the holotype was fairly dark when photographed, and more samples are needed to confirm this. According to MolD, the following combination of nucleotide position is diagnostic for the new subspecies among all other taxa in the subgenus Phylacomantis , including nominal G. c. corvus : (positions according to the full 16S sequence of G. pseudoasper, AB 325880): “A” at site 1019, “G” at site 1054.

Description of the holotype. Adult male in good state of preservation ( Fig. 6 ), with part of the ventral surface of left thigh cut and opened for tissue sampling and femoral gland inspection; skin on right thigh also cut. SVL 39.1 mm; for other measurements see Table 2 . Body somewhat stout; head longer than wide, slightly narrower than body; snout rounded in dorsal and lateral views; nostrils directed laterally, much nearer to tip of snout than to eye; canthus rostralis well defined, straight; loreal region concave; tympanum distinct, rounded, its horizontal diameter 60% of eye diameter; supratympanic fold distinct, regularly curved from eye to posterior edge of tympanum, then running straight towards forelimb insertion; tongue ovoid, distinctly bifid posteriorly; vomerine teeth present as two distinct rounded aggregations posteromedially from choanae; choanae rounded; maxillary teeth present. Vocal sacs on throat clearly recognizable as distinct lateral skin folds, the right sac partly distended, the left sac not distended. Arms slender; subarticular tubercles single; paired outer and unpaired inner metacarpal tubercles present and distinct; fingers without webbing; finger disks triangular, distinctly enlarged; nuptial pads absent. Hind limbs slender; tibiotarsal articulation reaching between nostrils and snout tip when hindlimbs are adpressed along body; lateral metatarsalia partly connected; inner metatarsal tubercle distinct, outer metatarsal tubercle small but distinct; webbing of foot 1(1), 2i(1.5), 2e(1), 3i(2), 3e(1.25), 4i(2.5), 4e(2.25), 5(1). Skin distinctly granular on dorsum, with a series of irregular longitudinal rows of tubercles and discontinuous ridges. Ventrally, smooth on throat and chest and finely granular on belly. Femoral macrogland (“Type 2”, according to Glaw et al. 2000) distinctly recognizable in internal and external view, containing ca. 45 single gland granules.

After 7 years in ethanol ( Fig. 6 ), dorsum almost uniformly brown, washed with some poorly contrasted darker and lighter tones. Upper and (more distinctly) lower lip with alternating light and dark bars (the light bars distinctly narrower). Hindlimbs dorsally brown with 4–5 dark brown crossbands on shank and thigh. Flanks dark brown with whitish spotting. Belly cream with irregular brown mottling. Vocal sacs blackish-gray. In life ( Fig. 5 ), color was similar, with a predominance of dark brown color dorsally and ventrally. Eyes had a grayish brown iris, with a vertical dark brown bar medially both in its upper and lower half.

Variation. The two female paratypes for which measurements are available agree morphologically with the male holotype ( Table 2 ), but are slightly smaller (SVL 38.0–38.5 vs. 39.1 mm); they lack femoral glands and vocal sacs. In life, all three paratypes ( Fig. 5 ) had orange-brown color elements dorsally. ZSM 505/2009 from Makira had yellow color ventrally, especially in the inguinal region and on thighs and shanks ( Fig. 5 ).

Etymology. The subspecies epithet is derived from the Malagasy noun “bakilana” = a “piece, scrap, morsel, or fragment”, referring to the tiny fragments of forest where populations were discovered, and also referring to the identity of a subspecies as a putative fragment of a species-level lineage. The name is used as a noun in apposition.

Distribution. So far known only from three localities comprised by the type series (Andranonafindra Forest, Irogno Forest, Makira west slope). None of the known localities of G. c. bakilana ssp. nov. ( Fig. 2 ) is situated in a protected area, although paratype ZSM 505/2009 was found only 5–6 km west and south of the borders of the Makira Natural Park and therefore might be present in the reserve. The known elevational range is 600–1200 m a.s.l.

Natural history. At Makira, specimens were observed along a rather large rocky stream in a largely deforested area, at the western edge of the reserve, while at other nearby sites within primary rainforest, no further specimens were found. At Andranonafindra, specimens were encountered in the early evening around 19–20 h along a narrow stream in an isolated valley forest fragment. One specimen (probably the holotype) was heard calling but could not be recorded. The forest fragment contained actively burning charcoal pits, and lies directly beside a large road built in order access the nearby hills for mining purposes. The hills nearby are largely denuded of forest except a narrow riparian strip, which however harbors a moderately diverse amphibian fauna. The Irogno specimen was found on a dead tree near rocks along a river.

Figures

FIGURE 2. Map of Madagascar showing collection sites of genotyped samples of Gephyromantis (Phylacomantis) used in this study. Note that the sites represent the entire known ranges of the respective species except for G. pseudoasper, which has been collected also in other sites of northern and northeastern Madagascar, for G. atsingy, which has also been recorded from Beanka, and for G. corvus, which has been recorded from the Makay massif (record in need of confirmation). Basemap shows vegetation types according to the CEPF Madagascar Vegetation Mapping Project (https://web.archive.org/web/20170615094352/http:// vegmad.org/). Colors represent the following vegetation types: light green = humid forests, red = dry deciduous forests, orange = spiny forest, light blue = western subhumid forests; light yellow = grassland.

FIGURE 5. Photographs of type specimens of Gephyromantis (Phylacomantis) corvus bakilana ssp. nov. in dorsolateral and ventral views in life.A, B, male holotype ZSM 63/2016 (MSZC 202) fromAndranonafindra forest. C, female paratype UADBA- MSZC 223 from Irogno forest; D, female paratype ZSM 64/2016 (MSZC 227) from Irogno forest; E, F paratype ZSM 505/2009 (DRV 5801) from near the Makira Reserve (western slope). Photographs not to scale.

FIGURE 6. Preserved holotype of Gephyromantis (Phylacomantis) corvus bakilana ssp. nov. (ZSM 63/2016; MSZC 202) in dorsal and ventral views.