Mantidactylus paidroa, Bora, Parfait, Ramilijaona, Olga, Raminosoa, Noromalala & Vences, Miguel, 2011

Bora, Parfait, Ramilijaona, Olga, Raminosoa, Noromalala & Vences, Miguel, 2011, A new species of Mantidactylus (subgenus Chonomantis) from Ranomafana National Park, eastern Madagascar (Amphibia, Anura, Mantellidae), Zootaxa 2772, pp. 52-60 : 53-58

Mantidactylus paidroa sp. nov.

( Fig. 1 a–c)

Remarks. This species has been referred to as Mantidactylus sp. 59 by Vieites et al. (2009) and Grosjean et al. (in press).

Holotype. ZSM 1777/2008 (field number ZCMV 7108), adult male ( Fig. 1 ), collected by P. Bora, J. Solo and D. Razafindraibe on 24 January 2008 at a site locally named Ankerana, in Ranomafana National Park, Southern Central East of Madagascar (21°15.582’S, 47°25.320’E), approximately 963 m above sea level.

Paratypes. ZSM 1778/2008 (field number ZCMV 7109, male) and ZSM 1776/2008 ( ZCMV 7107, female), same collecting data as holotype.

Diagnosis. Assigned to the genus Mantidactylus based on the presence of an intercalary element between terminal and subterminal phalanges of fingers and toes (verified by external observation), and of a central depression in femoral glands and presence of a rudimentary femoral gland in the female. Within Mantidactylus , assigned to the subgenus Chonomantis based on: (a) a specialized funnel-mouth tadpole, (b) a sharp dorsolateral colour border between dorsal and lateral coloration, (c) presence of a frenal stripe, (d) diurnal calling activity close to streams, (e) intersexual difference in tympanum size, (f) relatively small size (male SVL 22 mm).

Mantidactylus paidroa sp. nov is distinguished from all other species in the subgenus Chonomantis by presence of serial double notes in advertisement calls (vs. single notes) and a substantial genetic differentiation (see below). In addition, it is distinguished from Mantidactylus aerumnalis , M. brevipalmatus , M. charlotteae , and M. delormei by a bigger ratio of tympanum/eye diameter in males (1.4–1.5 vs. 0.7–1.3); from M. aerumnalis , M. charlotteae , M. opiparis , M. melanopleura , and M. zipperi by a lower amount of webbing on fifth toe (2 vs. 0.75–1.5 phalanges free of web); from M. brevipalmatus and M. delormei by smaller body size (male SVL 22 vs. 28–35 mm) and by shorter hindlimbs (tibiotarsal articulation reaching anterior eye corner vs. reaching beyond snout tip); from M. opiparis , M. melanopleura and M. charlotteae by presence of distinct and rather large femoral glands in males (vs. small glands), from Mantidactylus aerumnalis by presence of a frenal stripe between forelimb and eye (vs. absence); from M. aerumnalis , M. opiparis , and M. zipperi by a well-delimited narrow extension of the frenal stripe (bending upwards) between eye and nostril (vs. absence), and from M. aerumnalis , M. melanopleura and M. opiparis by having the third toe longer than the fifth (vs. fifth toe longer than third). Mantidactylus paidroa is morphologically most similar to M. albofrenatus from which it can be mainly distinguished by the throat colouration, which has a continuous median white line (vs. a row of spots in M. albofrenatus ). Tadpoles of M. paidroa differ from those of all other Chonomantis by the presence of very few keratodonts on the upper labium of the oral disk (vs. complete absence; see Grosjean et al. in press). Table 1 includes a comparison of diagnostic characters in Chonomantis species.

Throat black or black with a grey with light with black, with light black or dark black or light grey–

coloration dark brown, distinct large white indistinct, small white brown, with a dark yellowish, with with a white stripe spots weak darker spots which median line or brown, a rather broad median line which is forming a marbling form a row of spots with a light median and spots continued median row median row, median line stripe which onto the ven- sometimes or row of begins as dister fusing to a spots tinct white spot median close to the lip stripe

...... continued Etymology. The specific name—paidroa—refers to the typical advertisement call of the species, and derives from Malagasy words paika (meaning notes) and roa (double or two) (according to Malagasy grammar, the ending —ka is replaced by —d in the composite word). The name is used as an invariable noun in apposition.

Description of the holotype. SVL 22.3 mm. Body relatively slender; head longer than wide, of same width as body; snout rounded in dorsal view, slightly pointed in lateral view; nostrils directed laterally, slightly protuberant, nearer to tip of snout than to eye; canthus rostralis rather indistinct, straight; loreal region concave; tympanum distinct, oval, wider horizontally than vertically, its horizontal diameter 143% of eye diameter; supratympanic fold indistinct; tongue absent, taken for tissue sampling; vomerine teeth distinct, one rounded aggregation on each side of buccal roof, positioned posteromedian to choana; choanae small, rounded. Arms slender, subarticular tubercles distinct, single; inner metacarpal tubercle distinct and ovoid, outer metacarpal tubercle dinstinct but smaller and rounded; fingers without webbing; comparative finger length 1<2<4<3, second finger distinctly shorter than fourth finger; finger disks slightly enlarged; nuptial pads absent. Hindlimbs slender; tibiotarsal articulation reaches the anterior eye corner; lateral metatarsalia not connected; comparative toe length 1<2<5<3<4; third toe slightly longer than fifth toe; inner metatarsal tubercle distinct, outer metatarsal tubercle not recognizable; webbing between toes weakly expressed, formula 1 (1), 2i (>>1), 2e (1), 3i (2.25), 3e (2), 4i (3.5), 4e (3.25), 5 (2). Exact extension of web on 2i cannot be determined more in detail because only one subarticular tubercle is recognizable. Dorsal skin smooth; dorsum with distinct dorsolateral folds; ventral skin smooth, slightly granular in the cloacal region; no distinct tubercles in the cloacal region. Femoral glands large and distinct (length 5.0, width 3.5 mm, distance between internal borders of glands on opposite thighs 0.7 mm (almost in contact in the cloacal region), of type 3 with central depression as defined by Glaw et al. (2000).

Colour of the holotype. Colour in life ( Fig. 1 a–c) is dorsally light brown with irregular black blotches, with a conspicuous dorsolateral bold black border that separates the dorsum from the dark brown flanks, which have a few irregular bronze and white spots. From the insertion of forelimbs there is a white frenal stripe running under the tympanum and the eye, bending upward anterior to the eye and reaching the nostril. In the area between upper lip and nostril there are small bronze to light brown flecks. The iris is light brown in its upper and lower parts, with reddish brown colour in its anterior and posterior parts. The hindlimbs are light brown with dark brown transversal stripes. The ventral side is dark brown on the throat and greyish on the venter, with rounded white spots and a discontinuous median narrow white stripe running from the snout tip to the venter. The limbs are ventrally blackish with dark grey blotches. After two years in preservative, the colour tones are much less contrasted and especially the white and bronze elements have partly faded to dirty grey.

Variation. The male paratype is morphologically similar to the holotype. The female paratype, in contrast, in preservative has a much lighter dorsal and ventral colouration with only indistinct white ventral spots and an indistinct white midventral line. The female has rudimentary femoral glands.

Measurements. All given in mm. The first value refers to the holotype, the second and third values (in parentheses, male and female) to the paratypes. SVL 22.3 (22.0; 27.0), HW 7.3 (7.4; 8.0), HL 9.5 (9.0; 10.0), TD 3.3 (3.3; 2.4), ED 2.3 (2.2; 2.3), END 2.4 (2.2; 2.4), NSD 1.7 (1.7; 1.8), NND 3.0 (3.3; 3.3), FORL 14.3 (13.3; 16.0), HAL 6.2 (6.3; 7.0), HIL 35.0 (36.0; 41.5), FOTL 15.5 (16.0; 18.3), FOL 10.7 (10.8; 12.5), TIL 11.1 (11.1; 13.0).

Natural History. Calls of Mantidactylus paidroa were heard only at the type locality, Ankerana, in Ranomafana National Park, which is also the only locality where adults were collected. Other syntopic anurans at this site included two Chonomantis species ( Mantidactylus opiparis , M. melanopleura ) as well as Mantidactylus biporus , Gephyromantis asper , G. tschenki , and Stumpffia sp.

The type locality is characterized by the presence of various rocks of different size along a small, slow-running stream in rainforest. Specimens were found in humid sites under big rocks. Calls were emitted by the holotype during the day, on 24 January 2008 between 13:30–15:30. The two paratypes were collected close to the holotype. The female was found next to a rock under which the second male was calling, at about 5 m distance from the collecting site of the holotype.

The tadpole of M. paidroa is described in detail in Grosjean et al. (in press). It is of the funnel-mouthed type typical for Chonomantis , but as a character state unique in the subgenus, it has rudimentary labial teeth (keratodonts).

Advertisement calls. The call of Mantidactylus paidroa consists of a series of pulsatile note pairs ( Fig. 2 ). One completely recorded series had a duration of 47 seconds. At the beginning of the series, five single notes were emitted, followed by 33 note pairs, with a single note emitted in one case in-between two note pairs. Call frequency ranged from 1500–5900 Hz. Temporal call parameters are as follows: note length of single notes 8–14 ms (10.6±10.6 ms; n= 5); note length of first note in note pairs 12–14 ms (12.6±0.8 ms; n=11); note length of second note in note pairs 12–16 ms (13.4±1.1 ms; n=11); interval between single notes 908–1915 ms (1218.5±468.2 ms; n=4); interval between notes in note pairs 100–135 ms (116±8.6 ms; n=11); interval between note pairs 479–1471 ms (980.7±368.7 ms; n=11). For comparison of some call characters with other species in the subgenus see Table 1 .

Genetic divergence. In the alignment of 458 nucleotides of the 16S rRNA gene (after deleting portions at the beginning and the end of the DNA fragment that were missing in some taxa), the male paratype of Mantidactylus paidroa differed by a single substitution from the holotype and female paratype, which had identical sequences. The new species was strongly differentiated from all other species of Chonomantis (sequences as reported by Vieites et al. 2009). We found 24–46 substitutions in pairwise comparisons to all other species, corresponding to 5.6– 10.8% uncorrected pairwise sequence divergence (p-distances). The lowest distances (24–25 substitutions; 5.6– 5.8% divergence) were found to Mantidactylus brevipalmatus . For a preliminary phylogenetic analysis of the 16S sequences that however could not satisfyingly resolve relationships among species of Chonomantis , see supplementary information of Vieites et al. (2009) where the species is included as Mantidactylus sp. 59.

Figures

FIGURE 1. (a), (b) and (c), Photographs of male holotype of Mantidactylus paidroa (ZSM 1777 / 2008) in life (SVL 22.3 mm), in dorsolateral and ventral views.

FIGURE 2. Sonagrams and oscillograms of parts of a series of double notes, recorded from the holotype of Mantidactylus paidroa on 24 January 2008; (a) fragment of the call with 8 double notes; (b) enlarged view of two double notes.

Tables

TABLE 1. Morphometric ratios and distinctive morphological and bioacoustic characters in Mantidactylus paidroa sp. nov. compared with other species of Chonomantis, based on data published by Vences & Glaw (2004). Abbreviations used: SVL, snout-vent length; TD, tympanum diameter; ED, eye diameter; FOL, foot length; HAL, hand length; RHL, relative hindlimb length; TT, tibiotarsal articulation. Measurement values are mean ± standard deviation, followed by minimum – maximum values in parentheses. Data for M. delormei are based on the female holotype and photos of additional specimens in Glaw & Vences (2007) for colour in life.

	M. paidroa sp. nov.	M. aerumnalis	M. albofrenatus	M. brevipalmatus	M. charlotteae	M. delormei	M. melanopleura	M. opiparis	M. zipperi
SVL males (mm)	22.0–22.3	22.8–26.6	19.3–23.0	27.6–35.3	22.4–26.2	--	29.9–39.5	23.8–26.1	21.5–23.4
SVL females (mm)	27.0	28.3–31.0	25.3–27.1	34.8–44.9	26.3–32.2	38.9	32.3–40.5	27.0–33.2	29.5
TD/ED ratio males	1.45 (1.4–1.5)	0.77 ± 0.08 (0.67–0.87)	1.27 ± 0.10 (1.10–1.38)	1.17 ± 0.08 (1.05–1.31)	0.92 ± 0.13 (0.70–1.13)	--	1.24 ± 0.16 (0.93–1.47)	1.34 ± 0.14 (1.20–1.50)	1.24 ± 0.16 (1.03–1.44)
TD/ED ratio females	1.04	0.68 ± 0.05 (0.61–0.74)	0.73–0.74	0.82 ± 0.07 (0.70–091)	0.75 ± 0.08 (0.62–0.84)	0.66	0.80 ± 0.03 (0.76–0.85)	0.81 ± 0.09 (0.62–0.91)	0.79
FOL/SVL ratio	0.48 (0.46–0.49)	0.56 ± 0.03 (0.51–0.60)	0.51 ± 0.05 (0.46–0.63)	0.66 ± 0.04 (0.60–0.71)	0.49 ± 0.03 (0.45–0.56)	0.64	0.54 ± 0.06 (0.51–0.80)	0.54 ± 0.04 (0.49–0.62)	0.52 ± 0.03 (0.47–0.55)
HAL/SVL ratio	0.28 (0.26–0.29)	0.29 ± 0.01 (0.27–0.32)	0.29 ± 0.02 (0.27–0.31)	0.30 ± 0.02 (0.27–0.32)	0.29 ± 0.01 (0.27–0.33)	0.30	0.27 ± 0.01 (0.25–0.31)	0.29 ± 0.02 (0.25–0.32)	0.30 ± 0.02 (0.27–0.33)
RHL of most specimens	TT reaches at most nostril	TT reaches snout tip or beyond	TT reaches at most nostril	TT reaches beyond snout tip	TT reaches at most nostril	--	TT reaches beyond snout tip	TT reaches snout tip or beyond	TT does not reach snout tip
Webbing of toe 5	2	0.75–1	1.5–2	2	1.25	--	1	1	1.5
Femoral glands in males	large, prominent	large, prominent	large, prominent	large, very prominent	small to large, not very prominent	--	small, i ndistinct	small, indistinct	large, not very prominent
Frenal stripe between forelimb and eye	present	absent	present	present	present	present	present	present	present
Frenal stripe between eye and nostril	present, reaches close to nostril	absent	present, reaches nostril or close to it	present, reaches close to nostril	usually stops anterior to the eye	slightly fading anterior to eye	present, reaches nostril or close to it	fades ante- rior to eye	fades anterior to eye