Gephyromantis hintelmannae, Wollenberg, Katharina C., Glaw, Frank & Vences, Miguel, 2012

Wollenberg, Katharina C., Glaw, Frank & Vences, Miguel, 2012, Revision of the little brown frogs in the Gephyromantis decaryi complex with description of a new species, Zootaxa 3421, pp. 32-60 : 52-54

Gephyromantis hintelmannae sp. nov.

Remark. This species corresponds to the CCS Gephyromantis sp. 8 of Vieites et al. (2009) and Kaffenberger et al. (2012).

Holotype. ZSM 2500/2007 ( ZCMV 5230), adult male, collected in the vicinities of Ambohitsara village on the way to a forest fragment locally named Tsitolaka, south-eastern Madagascar, 21° 21.431' S, 47° 48.941' E, at ca. 300 m above sea level, by K. C. Wollenberg, P. Nürnberger, E. Rajeriarison and T. Rajoafiarison on 3 March 2007.

Paratypes. ZSM 2499/2007 ( ZCMV 5229), and 2501/2007 ( ZCMV 5231), adult males, same locality and collectors as holotype; ZSM 2502/2007 ( ZCMV 5232), ZSM 2503/2007 ( ZCMV 5233), and ZSM 2504/2007 ( ZCMV 5235), same locality and collectors as holotype. ZSM 494–499/2009 (field numbers ZCMV 8574, ZCMV 8628–8632), five males and one female from a site near Ankazorokana at geographical coordinates 21°20.127' S, 48°07.663' E, 142 m a.s.l., collected on 20 February 2009 by E. Rajeriarison, T. Rajoafiarison, K.C. Wollenberg and M. Vences.

Diagnosis. A member of the subgenus Gephyromantis in the genus Gephyromantis on the basis of (1) presence of intercalary elements between ultimate and penultimate phalanges of fingers and toes (verified by external examination), (2) small size (SVL below 35 mm), (3) slightly enlarged terminal discs of fingers, (4) presence of outer metatarsal tubercle, (5) absence of webbing on hands and presence of only rudimentary webbing on feet, (6) tight connection of tissue surrounding the two lateral metatarsalia, (7) presence of femoral glands in males, (8) presence of paired or bilobed blackish vocal sacs in males, (9) diurnal calling behavior not concentrated at water bodies.

Within the subgenus, distinguished from all other species by combination of (1) comparatively moderate size (male SVL 24–26 mm), (2) dorsum in general smooth with only a low number of tubercles and with inner and outer dorsolateral ridges indistinct, usually only traces of inner dorsolateral ridge recognizable, (3) upper lip with light gray or white color usually not interrupted by larger dark markings, (4) lower lip ventrally without a distinct alternating series of brown and yellowish markings; (5) dorsal color relatively uniform, grayish with light brown tones in life, (6) hindlimbs not particularly long, not reaching snout tip, (7) calls consisting of a rather long series of>30 notes of indistinctly pulsed structure with a low note repetition rate of 3.6–4.6/s.

Assigned to the group of species here informally defined as the Gephyromantis decaryi complex based on its molecular phylogenetic relationships (see above) and its calls which are long series of notes with a low note repetition rate. Distinguished from G. decaryi by much less continuous expression of inner and outer dorsolateral ridges which often are lacking completely (versus distinct and usually not interrupted, Fig. 6 ), by the lack of distinct dark patches interrupting light color on upper lip (vs. presence), by the shorter limbs (tibiotarsal articulation not reaching snout tip vs. reaching beyond snout tip), and by a higher number of notes (>100 versus usually <50) in advertisement calls.

Distinguished from G. verrucosus by a dorsum smooth with small tubercles and traces of dorsolateral ridges (versus large regular granules; Fig. 6 ), by the relatively large and distinct femoral glands in males (versus smaller and indistinct), by the absence of distinct dark patches interrupting light color on upper lip in most specimens (versus presence), by usually a uniform grayish dorsum (versus a contrasted pattern), by a higher number of notes (>100 versus <80), and by a shorter note duration (81–103 ms versus 123–157 ms; see Table 2 ) in advertisement calls. G. hintelmannae differs from all other species in the G. decaryi complex with the exception of the population from Manombo by morphometry ( Fig. 5 ).

Etymology. The name is a patronym dedicated to Mrs. Elisabeth Hintelmann (Munich), to acknowledge her dedication to donating the international R. J. H. Hintelmann scientific award for Zoological Systematics since 2000, and thereby significantly encouraging the work of young systematists.

Description of the holotype. Specimen in excellent state of preservation, but right femur is fractured as tissue was taken for DNA analyses. SVL 24.8 mm. For measurements see Table 1. Body slender, ratio of head length to head width HL/HW = 1.13, head slightly wider than body, snout pointed in dorsal view, rounded in lateral view; nostrils directed posterolaterally, slightly protuberant, canthus rostralis moderately distinct, rounded; loreal region concave; tympanum distinct, rounded, ratio of tympanum diameter to eye diameter TD/ED = 0.59; supratympanic fold weakly developed; tongue ovoid, posteriorly bifid; maxillary teeth present; vomerine teeth absent; choanae rounded. Arms slender; distinct single subarticular tubercles; inner and outer metacarpal tubercles distinct; fingers without webbing; relative length of fingers 1<2<4<3, fourth finger longer than second finger; finger disks distinctly enlarged; nuptial pads absent. Hindlimbs slender; tibiotarsal articulation reaches the snout tip when the hindlimb is adpressed along the body; lateral metatarsalia strongly connected; inner and outer metatarsal tubercles distinct; traces of webbing between toes; relative length of toes 1<2<3=5<4; fifth toe of same length as third toe. Skin on the dorsal surface smooth, with only one weakly developed dorsolateral ridge. Very weakly developed folds on the lateral sides. Ventral skin smooth on throat, chest and limbs, granular on central and posterior belly, and coarsely granular on the lateral belly. The subgular vocal sac is laterally black, probably indicating a paired or bilobed shape when inflated, femoral glands are a large distinct patch in external view.

After almost three years in preservative, dorsally uniformly grayish brown with a lighter snout region and few dark dorsolaterally scattered spots, color between the eyes slightly darker forming a broad band between the eyes. Around the anterior margin of the eyes, a thin dark vertical line transects the lip. On the flanks, the dorsal color gradually fades into the light ventral coloration. The tympanic area is dark brown; this color is dorsally sharply limited by the supratympanic fold, which is embedded in a black stripe with sharp borders, and ventrally by a white line which runs from the snout tip to the forelimb insertion, and partly continues on the upper arm. Contrast between dark dorsal coloration and white lip stripe is less distinct between eye and nostril. Along the light lip stripe scattered small black markings, which do not form a regular alternating pattern. Very faint brownish crossbands on limbs. Ventrally, the color is light tan, shanks and thighs are brownish. A white irregular median band, bordered by tan coloration and some additional white blotches, runs along the throat and chest, which also has some additional white pigment. The lower lip shows ventrally a distinct alternating brown-white pattern. The anterior belly has some white pigment on tan background.

Color in life was very similar to that in preservative ( Fig. 4 e–f). The dorsal ground color was gray with some light brown shades. Ventrally, the stripe on the throat and the whole belly was silvery white, femoral glands were dark yellow. The iris was light brown in its upper part and dark brown in its lower part.

Variation. For measurements see Table 1. The two ZSM paratype specimens from Ambohitsara are similar in appearance. The male paratype ZCMV 5231 (2501/2007) has a much lighter dorsal coloration which appears grayish-pinkish after almost three years in preservative. The male paratype ZCMV 5229 (ZSM 2499/2007) has a more strongly developed pattern on darker dorsal coloration. The specimens from Ankazorokana were collected after completion of the morphometric analyses and therefore not measured in detail. However, they perfectly agree in coloration and external morphology (dorsal skin texture) with those from Ambohitsara.

Natural history. We collected calling males near Ambohitsara village and at Ankazorokana in dense fern shrubs and secondary vegetation. Specimens were sitting in the shrubs, at very low perch heights of less than 10 cm, or on the ground, calling during the day. They were locally common but rather evenly spaced, not forming aggregations, and not close to water, suggesting a possible nidicolous reproduction as in other species of the subgenus Gephyromantis .

Advertisement calls. Calls from Ambohitsara were very long series of notes (ca. 123 notes in one fully recorded call that lasted ca. 32.5 seconds; note repetition rate 3.8/s). Fundamental frequency was 1800–2200 Hz, dominant frequency between 3800–4200 Hz, and a weak frequency component was also recognizable at 5800–6000 Hz. Calls from Ankazorokana agree with this description.

Distribution. Known from (1) the type locality, near Ambohitsara village, at ca. 300 m a.s.l., and (2) near Ankazorokana at 142 m a.s.l., ca 30 km east of the type locality.

Figures

FIGURE 4. Comparative dorsolateral and ventral views of males of the four species respectively candidate species in the Gephyromantis decaryi complex. (a, b) Gephyromantis decaryi from Ranomafana, specimen photographed in 2007 and preserved in the UADBA collection; (c, d) Gephyromantis verrucosus from Manombo, specimen ZSM 2508 / 2007 (field number ZCMV 5495); (e, f) Gephyromantis hintelmannae from Ambohitsara, holotype specimen ZSM 2500 / 2007 (field number ZCMV 5230); (g, h) Gephyromantis sp. 7, specimen preserved in UADBA (field number ZCMV 5484).

FIGURE 5. Morphometric differentiation of specimens from Ranomafana (G. decaryi, open gray dots), from Ambohitsara (G. hintelmannae, filled gray dots), from Manombo (G. verrucosus, red filled dots), and Manakara (G. sp. 7, filled black dots). Polygonal shapes denote morphological differences among groups. A - G. verrucosus and G. sp. 7 differ in PCs 3 and 5; B – G. decaryi shows different PC 1 / SVL values as compared to all other species of the G. d e c a r y i complex. C – G. hintelmannae is well distinguished from G. sp. 7 by the residuals of TL and HL, but shows some overlap with specimens belonging to G. v e r r u - cosus.

FIGURE 6. Photographs of dorsal skin structure in preserved specimens of (a) Gephyromantis decaryi (ZSM 2497 / 2007; field number ZCMV 5223), (b) G. verrucosus (ZSM 2462 / 2007; ZCMV 5459), (c) G. hintelmannae (holotype ZSM 2500 / 2007; ZCMV 5230), and (d) G. sp. 7 (ZSM 2492 / 2007; ZCMV 5485). Note continuous dorsolateral ridges in G. decaryi, discontinuous ridges and elongated tubercles in G. verrucosus, and relatively smooth skin with weakly expressed ridges in G. hintelmannae and G. sp. 7. Scale bars represent 1 mm.