Leptolalax maculosus, Rowley & Tran & Le & Dau & Peloso & Nguyen & Hoang & Nguyen & Ziegler, 2016

Rowley, Jodi J. L., Tran, Dao T. A., Le, Duong T. T., Dau, Vinh Q., Peloso, Pedro L. V., Nguyen, Truong Q., Hoang, Huy D., Nguyen, Tao T. & Ziegler, Thomas, 2016, Five new, microendemic Asian Leaf-litter Frogs (Leptolalax) from the southern Annamite mountains, Vietnam, Zootaxa 4085 (1), pp. 63-102 : 93-96

Leptolalax maculosus sp. nov.

Figs. 8C , 9C , 13 .

Holotype. UNS 00513, adult male, in dry stream bed in evergreen forest in Phuoc Binh National Park , Ninh Thuan Province, Vietnam (12.0152º N, 108.7271º E, 900 m elevation, Fig. 1 ). Collected on 24 September 2011 by Dao T. A. Tran and Duong T. T. Le.

Paratypes. ZFMK 96600, adult male from same date and location as holotype. AMS R 177660, adult male, and UNS 00514, adult female, collected on 27 September 2011 from evergreen forest in Phuoc Binh National Park, Ninh Thuan Province, Vietnam (12.0413º N, 108.7385º E, 1166 m elevation). All specimens were collected by Dao T. A. Tran and Duong T. T. Le.

Etymology. The specific name “ maculosus ”, meaning spotted, speckled, mottled or variegated, is used as an adjective in reference to the more mottled dorsal pattern of this species.

Diagnosis. Assigned to the genus Leptolalax on the basis of the following characters: small size, rounded finger tips, the presence of an elevated inner palmar tubercle not continuous to the thumb, presence of macroglands on body (including supra–axillary, pectoral, femoral and ventrolateral glands), the absence of vomerine teeth, the presence of tubercles on eyelids, and anterior tip of snout with pale vertical bar ( Dubois 1983; Lathrop et al. 1998; Delorme et al. 2006). Leptolalax maculosus sp. nov. is distinguished from its congeners by a combination of (1) supra-axillary and ventrolateral glands present; (2) dark brownish red ventral surface with white speckling; (3) small/medium SVL for the genus (24.2–26.6 mm in three adult males, 27.0 mm in one female); (4) toes lacking webbing and lateral fringes; (5) tibia length 48–50% of SVL in males; (6) pectoral gland 3.5–4.2% of SVL in males, (7) mostly smooth dorsum, (8) iris copper in upper half and gold in lower half (9) distinct black supratympanic line present, (10) an advertisement call with 7–38 notes, lacking a distinct introductory note.

Description of holotype. Head width equal to head length; snout rounded in dorsal view and slightly truncate in profile, projecting slightly beyond margin of the lower jaw; nostril closer to snout than to eye; canthus rostralis indistinct, gently rounded; lores straight; pupil vertical; eye diameter slightly larger than snout length; tympanum distinct, round, diameter smaller than that of the eye; tympanic rim slightly elevated relative to skin of temporal region; vomerine teeth absent; pineal ocellus absent; vocal sac openings slit–like, located posteriolaterally on floor of mouth; tongue wide with broad, shallow notch at posterior tip; supratympanic ridge distinct, running from eye to axillary gland. Tips of fingers rounded, very slightly swollen; relative finger lengths I <IV = II <III; nuptial pad absent; subarticular tubercles absent; a large, round inner palmar tubercle distinctly separated from smaller, laterally compressed outer palmar tubercle; finger webbing and dermal fringes absent. Tips of toes like fingers; relative toe length I <II <V <III <IV; subarticular tubercles absent; large, oval inner metatarsal tubercle present, outer metatarsal tubercle absent; toe webbing rudimentary, most visible between toes II and III; slight lateral fringes present. Tibia 48% of snout–vent length; tibiotarsal articulation reaching tip of snout. Skin on dorsum smooth; ventral skin smooth; pectoral gland oval, 1.0 mm diameter; femoral gland oval, approximately 1.7 mm diameter, on posteroventral surface of thigh, slightly closer to knee than to vent; supra–axillary gland oval, raised, 1.3 mm diameter. Ventrolateral glands forming broken lines.

Colour of holotype in life. Dorsal surface dark brown with irregular, darker brown blotch down back; small, pale brown blotches scattered over dorsum; dark interorbital bar with pale copper edging anteriorly; two small, pale copper V-markings between axilla ( Fig. 13A, B ). Black line along supratympanic ridge, terminating above axilla, encompassing most of tympanum; irregular copper band under black supratympanic line; transverse dark brown bars on dorsal surface of thighs, tibia, tarsus, lower arms, fingers and toes; elbows and upper arms copper; numerous, small darker brown spots on sides from groin to axilla. Brownish pink ventral surface with white speckling on ventral surfaces of throat, chest, belly, legs and arms. Supra-axillary gland copper; femoral glands white; pectoral glands white, ventrolateral glands white. Iris copper in upper half, gold in lower half, black reticulations throughout.

Colour of holotype in preservative. Dorsum medium brown with small, pale brown blotches on top of head, barely visible paler intraorbital blotch; dark brown/black banding on dorsal surface of tibiotarsus, antebrachium, hands and feet ( Fig. 8C ). Black blotch on groin. Ventral surface medium brown with white speckling. Macroglands creamy white.

Measurements (mm). Holotype: SVL 24.2, HDL 8.9, HDW 9.0, SNT 3.3, EYE 3.4, IOD 3.5, TMP 1.5, TEY 0.9, TIB 11.6, EN 2.3, IN 2.3, NS 1.1, ML 6.0, PL 10.1.

Variation: Measurements of the type series are shown in Tables 5–6 and representative photographs of paratypes are shown in Figs. 9C and 15. AMS R 177660 and to a lesser extent ZFMK 96600 have more distinct patterning, with paler blotches on the dorsum

Advertisement call. Call descriptions are based on the calls of two individuals, recorded at 23.3–24.1 ºC ambient temperature. Calls were an average of 907 ms in duration and consisted of 7–38 notes (Table 7, Fig. 6C ). Calls were highly amplitude modulated, with a slow rise in amplitude, and amplitude peaking towards the middle of each note. Notes near-invariably contained a single pulse. Notes were repeated an average of 17 notes/s, but note repetition rate was higher at the start of each call. The average dominant frequency was 2.7 kHz, with peak frequency spread over ~2.7–3.5 kHz. A fundamental frequency was not visible. To the human ear, the advertisement call of L. maculosus sp. nov. is a squealch grading gently into a chirp.

Ecology. All specimens of Leptolalax maculosus sp. nov. were found in evergreen forest between 900–1166 m elevation at Phuoc Binh National Park. Specimens were found within leaf-litter and in clay holes in a dry stream bed of 1.5–2.0 m width, connecting to a larger stream.

Distribution. Leptolalax maculosus sp. nov. is only known from Phuoc Binh National Park, Ninh Thuan Province, Vietnam. The maximum distance between known localities is only 3.2 km.

Comparisons. Leptolalax maculosus sp. nov. differs from all other Leptolalax species in mainland Southeast Asia on the basis of morphology, and from all congeners in the region for which comparable data is available on the basis of molecular and acoustic data.

The new species differs from L. aereus by ventral coloration and presence of distinct black supratympanic line, from L. bourreti by ventral coloration and male body size, from L. botsfordi by male body size and relative body weight (0.41–0.47 versus 0.75–0.94 g /mm in L. botsfordi ), from L. croceus by ventral coloration, presence of black supratympanic line and iris coloration; from L. eos by ventral coloration, male body size, presence of black supratympanic line and lateral fringes on toes; from L. firthi by ventral coloration, iris coloration and lateral fringes on toes; from L. fuliginosus by ventral coloration, male body size and iris coloration; from L. heteropus by ventral coloration and iris coloration; from L. kecil by ventral coloration, male body size and iris coloration; from L. melanoleucus by ventral coloration and iris coloration; from L. minimus by ventral coloration; from L. nahangensis by ventral coloration and male body size; from L. nyx by ventral coloration and male body size, from L pelodytoides by ventral coloration and male body size; from L. platycephalus by ventral coloration and male body size; from L. pluvialis by ventral coloration and male body size; from L. solus by ventral coloration, male body size and iris coloration; from L. sungi by ventral coloration, male body size and iris coloration; from L. tuberosus by ventral coloration, presence of black supratympanic line and skin texture; from L. ventripunctatus by ventral coloration and iris coloration; and from L. zhangyangpingi by ventral coloration, male body size and iris coloration. See Table 8 for details.

From members of the L. applebyi group, L. maculosus sp. nov. differs from all species by at least one morphological character (all following morphometric differences refer to males only). The new species differs from L. applebyi by having a significantly greater body size (Wilcoxon post-hoc Z=2.7, p=0.007), greater relative head width (Wilcoxon post-hoc Z=2.7, p=0.007), greater relative diameter of the eye (Wilcoxon post-hoc Z=2.2, p=0.025), and greater relative pectoral gland size (Wilcoxon post-hoc Z=2.4, p=0.017). L. maculosus sp. nov. differs from L. bidoupensis by having a significantly greater relative tibia length (Wilcoxon post-hoc Z=2.4, p=0.018), and a bronze iris (versus reddish upper and silver below in L. bidoupensis ). L. maculosus sp. nov. differs from L. melicus by having a significantly greater body size (Wilcoxon post-hoc Z=2.6, p=0.009), and greater length between eye and tympanum (Wilcoxon post-hoc Z=2.1, p=0.034). L. maculosus sp. nov. differs from L. pyrrhops by having a significantly smaller body size (Wilcoxon post-hoc Z= -2.6, p=0.010), smaller relative length between eye and tympanum (Wilcoxon post-hoc Z= -2.4, p=0.018) and smaller relative diameter of the eye (Wilcoxon posthoc Z=-2.4, p=0.018). L. maculosus sp. nov. differs from L. ardens sp. nov. by having a significantly greater body size (Wilcoxon post-hoc Z=2.8, p=0.006). L. maculosus sp. nov. differs from L. pallidus sp. nov. by having a black supratympanic line (versus no black supratypmanic line in L. pallidus sp. nov) and smooth- finely shagreened skin texture (versus tuberculate in L. pallidus sp. nov). L. maculosus sp. nov. differs from L. kalonensis sp. nov. by having a significantly smaller body size (Wilcoxon post-hoc Z=-2.7, p=0.007). L. maculosus sp. nov. differs from L. tadungensis sp. nov. by having a significantly greater relative tibia length (Wilcoxon post-hoc Z=-2.5, p=0.013). See Table 4 and Fig. 5 .

The male advertisement call of L. maculosus sp. nov. differs from all species in the L. applebyi group. The call of the new species differs from L. applebyi in call duration, number of notes per call, an introductory note, and dominant frequency; from L. bidoupensis in call duration, average number of notes per call, presence of an introductory note, and average dominant frequency; from L. melicus in call duration, number of notes per call, having an indistinct introductory note, and dominant frequency; from L. pyrrhops by call duration, number of notes per call, having an indistinct introductory note, and dominant frequency; from L. ardens sp. nov. by call duration, number of notes per call and dominant frequency; from L. pallidus sp. nov. by call duration and number of notes per call; from L. kalonensis sp. nov. by average call duration, and number of notes per call; from L. tadungensis sp. nov. by call duration, number of notes per call, having a less distinct introductory note and different relative duration of introductory note. See Table 7 and Figs. 5–6 .

Leptolalax maculosus sp. nov. differs from all species within the L. applebyi group by>6.3% divergence at the 16S gene fragment examined. Interspecific variation in four L. maculosus sp. nov. collected from up to ~ 3 km apart was 0.0–0.2%.

Figures

FIGURE 1. Map showing the localities where specimens in the Leptolalax applebyi group were collected in Cambodia and Vietnam. Colours of localities assigned based on molecular lineages. Paler areas are higher elevation. Dark grey lines show country boundaries, pale grey lines show watershed boundaries and blue lines show rivers.

FIGURE 5. Advertisement calls of species in the Leptolalax applebyi group minus L. pyrrhops (i) 10 s waveform of relative amplitude (Rel. amp.) over time, (ii) waveform and (iii) corresponding 2 s spectrogram of representative call expanded from first section shown in i for (A) L. applebyi holotype AMS R 171703, (B) L. bidoupensis paratype UNS 00101 / AMS R 173135, (C) L. melicus holotype MVZ 258198, and (D) L. ardens sp. nov. paratype UNS 00534 / AMS R 176466. For ambient temperatures during recordings, see Table 4.

FIGURE 6. Advertisement calls of species in the Leptolalax applebyi group minus L. pyrrhops (i) 10 s waveform of relative amplitude (Rel. amp.) over time, (ii) waveform and (iii) corresponding 2 s spectrogram of representative call expanded from first section shown in i for (A) L. pallidus sp. nov. holotype UNS 00510, (B) L. kalonensis sp. nov. paratype IEBR A. 2014.21, (C) L. maculosus sp. nov. holotype UNS 0 0 513, (D) L. tadungensis sp. nov. AMS R 177666. For ambient temperatures during recordings, see Table 4.

FIGURE 8. Dorsal and ventral views of holotypes of (A) L. pallidus sp. nov. UNS 00510, (B) L. kalonensis sp. nov. IEBR A. 2014.14, (C) L. maculosus sp. nov. UNS 00513, (D) L. tadungensis sp. nov. UNS 00516. Scale bar = 5 mm.

FIGURE 9. Calling sites and representative habitats of species in the Leptolalax applebyi group. (A) L. ardens sp. nov., (B) L. kalonensis sp. nov., (C) L. maculosus sp. nov.. (D) stream in Kon Ka Kinh National Park, Gia Lai Province, where L. ardens sp. nov. males were observed 1 - 2 m from stream, calling under leaf-litter, (E) downstream from dry section of stream in Bidoup Nui Ba National Park, Lam Dong Province, where L. pallidus sp. nov. were observed calling, (F) dry stream bed in Song Luy Watershed Forest, Binh Thuan Province, where calling L. kalonensis sp. nov. were collected, and (G) dry stream bed in Ta Dung Forest, Dak Nong Province, where L. tadungensis sp. nov. were calling and collected.

FIGURE 13. Leptolalax maculosus sp. nov. in life (A) dorsolateral view of male holotype UNS 0 0 513, (B) anteroventral view of male holotype UNS 0 0 513, (C) male holotype AMS R 177660, (D) female paratype UNS 0 0 514.