Leptolalax kalonensis, 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 : 90-93

Leptolalax kalonensis sp. nov.

Figs. 8B , 9B , 11 .

Holotype. IEBR A.2014.15, adult male, collected from rocky crevice, 0.5 m from 4–5 m wide, rocky stream in disturbed evergreen forest in Song Luy Watershed Forest, Binh Thuan Province, Vietnam (11.2748º N, 108.2109º E; 200 m elevation; Figs 1 , 9F ). Collected 5 August 2011 by Dao T. A. Tran, David Kizirian, Truong Q. Nguyen, Pedro L. V. Peloso, and Cuong T. Pham.

Paratypes. AMNH A191768–9, 2 adult males, and IEBR A.2014.22, one adult female, collected on 6 August 2011; AMNH A191770, adult male collected on 11 August 2011; AMNH A191761 adult male collected on 12 August 2011; IEBR A.2014.18, adult male collected on 13 August 2011; all from disturbed evergreen forest in Song Luy Watershed Forest , Binh Thuan Province, Vietnam (11.2748º N, 108.2109º E; 200 m elevation) . AMNH A191762, AMNH A191765, AMNH A191763, IEBR A.2014.19, AMNH A191764, IEBR A.2014.21, AMNH A191767, seven adult males, and AMNH A191766, IEBR A.2014.20, two adult females, collected on 5 August 2011; IEBR A.2014.15, adult male, collected on 12 August 2011; IEBR A.2014.16 and IEBR A.2014.17, two adult males, collected on 13 August 2011 in disturbed evergreen forest in Song Luy Watershed Forest , Binh Thuan Province, Vietnam (11.2919º N, 108.2150º E, 571 m elevation). Paratypes were collected by Dao T. A. Tran, David Kizirian, Truong Q. Nguyen, Pedro L. V. Peloso, and Cuong T. Pham.

Etymology. Specific epithet “ kalonensis ” is in reference to the type locality of the species, which is in close proximity to the village previously known as Kalon.

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 kalonensis sp. nov. is distinguished from its congeners by a combination of (1) supra–axillary and ventrolateral glands present; (2) pale brownish pink ventral surface with white speckling; (3) small/medium SVL for the genus (25.8–30.6 mm in 16 adult males, 28.9–30.6 mm in three females); (4) toes lacking webbing and lateral fringes; (5) tibia length 45–52% of SVL in males; (6) pectoral gland 2.5–7.0% of SVL in males, (7) mostly smooth dorsum, (8) iris gold, coppery orange in upper third in some specimens (9) distinct black supratympanic line present in most specimens, (10) an advertisement call with 4–5 notes including introductory note, comprising almost one-third of each call duration.

Description of holotype. Head width slightly subequal to head length; snout slightly truncate in dorsal view and in profile, projecting slightly beyond margin of the lower jaw; nostril closer to snout than eye; canthus rostralis indistinct, gently rounded; lores sloping; pupil vertical; eye diameter smaller than snout length; tympanum indistinct, 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 small, 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, replaced by dermal ridges, distinct on base of toes II and III; large, oval inner metatarsal tubercle present, outer metatarsal tubercle absent; toe webbing rudimentary; lateral fringes absent. Tibia 46% of snout–vent length; tibiotarsal articulation reaching to anterior edge of eye. Skin on dorsum smooth; ventral skin smooth; pectoral gland oval, 1.0 mm diameter; femoral gland oval, 1.1 mm diameter, on posteroventral surface of thigh, closer to knee than to vent; supra–axillary gland oval, raised, 1.2 mm diameter. Ventrolateral glands indistinctly present as broken lines.

Colour of holotype in life. Dorsal surface brown with slightly darker interorbital bar; faint dark W-shaped marking between axilla ( Fig. 12A ). Darker brown line along supratympanic ridge, terminating above axilla, encompassing most of tympanum; transverse dark brown bars on dorsal surface of thighs, tibia, tarsus, lower arms, fingers and toes; elbows and upper arms paler brown; several small dark brown spots on sides from groin to axilla. Dark brownish ventral surface with white speckling on ventral surfaces of throat, chest and belly, more sparse on 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 greyish brown with darker brown, elongated, oval blotches and intraorbital blotch; dark brown/black banding on dorsal surface of tibiotarsus, antebrachium, hands and feet. Groin on blotch ( Fig. 8B ). Ventral surface cream. Macroglands creamy white.

Measurements (mm). Holotype: SVL 27.5, HDL 10.2, HDW 10.1, SNT 4.3, EYE 3.6, IOD 2.9, TMP 1.7, TEY 1.3, TIB 12.6, EN 2.5, IN 2.8, NS 1.6, ML 6.7, PL 11.5.

Variation. Measurements of the type series are shown in Tables 2–3 and representative photographs of paratypes are shown in Figs. 9B and 12 . AMNH A191768, AMNH A191769, IEBR A.2014.16, IEBR A.2014.17, and IEBR A.2014.22 are darker in dorsal colouration and have less distinct patterning. IEBR A.2014.18 and AMNH A191763 are pale and have only dark brown, rather than black markings. Specimens vary in degree of patterning on dorsum. Specimens vary in degree of medium brown speckling on venter; AMNH A191768, IEBR A.2014.16, AMNH A191762, IEBR A.2014.20, and AMNH A191766 have variably medium brown throats with white speckling and medium brown speckling on chest and belly (especially IEBR A.2014.16). The ventrolateral line varies in distinctness and completeness; the most distinct and complete in AMNH A191769.

Advertisement call. Call descriptions are based on the call of AMNH A191770, recorded at 26.4 ºC ambient temperature. Calls were an average of 201 ms in duration and consisted of 4–5 notes (Table 7, Fig. 6B ). Introductory notes of low relative amplitude were present in all calls, were an average of 29% of the call duration, and contained up to an average of 15 pulses. Non-introductory notes near-invariably contained a single pulse. Notes were repeated an average of 16 notes/s. The average dominant frequency was 2.8 kHz, spread more widely (2.6–2.9 kHz) in non-introductory notes. Harmonics and a fundamental frequency were not visible due to poor recording quality. To the human ear, the advertisement call of L. kalonensis sp. nov. is a short rasp, similar to an orthopteran.

Ecology. All specimens of Leptolalax kalonensis sp. nov. were found in evergreen forest between 200–791 m elevation in Song Luy Watershed Forest. Specimens were located on the ground, 0.5–4.0 m from 2–5 m wide, shallow, rocky streams ( Fig. 9F ). Forest in the area was disturbed secondary forest, consisting of discontinuous patches of small hardwoods, bamboo and shrubs. Forest on mountain slopes was replaced by plantations and cultivated fields.

Distribution. Leptolalax kalonensis sp. nov. is only known from Song Luy Watershed Forest in Binh Thuan Province, Vietnam. The greatest distance between known localities for the species is 43 km. Given the relatively large distance between localities, low elevation, and relatively larger streams, this species is likely to be more widely distributed than other species in the L. applebyi group.

Comparisons. Leptolalax kalonensis 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 black supratympanic line, from L. bourreti by ventral coloration, from L. botsfordi by ventral coloration, from L. croceus by ventral coloration, presence of black supratympanic line, and skin texture; 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, presence of black supratympanic line, skin texture and lateral fringes on toes; from L. fuliginosus by ventral coloration and iris coloration; from L. heteropus by ventral coloration and male body size; 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, from L pelodytoides by ventral coloration; 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 and iris coloration; from L. sungi by ventral coloration, male body size and iris coloration; from L. tuberosus by ventral coloration, iris coloration 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. kalonensis 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 larger body size (Wilcoxon post-hoc Z=4.0, p<0.001), larger relative tibia length (Wilcoxon post-hoc Z=2.8, p=0.005), greater relative diameter of the eye (Wilcoxon post-hoc Z=2.9, p=0.004), and larger relative pectoral gland size (Wilcoxon post-hoc Z=2.6, p=0.009). L. kalonensis sp. nov. differs from L. bidoupensis by having a significantly larger body size (Wilcoxon post-hoc Z=4.4, p<0.001), larger relative tibia length (Wilcoxon post-hoc Z=3.2, p=0.001), larger relative eye size (Wilcoxon post-hoc Z=2.3, p=0.019), and gold iris (versus reddish upper and silver below). L. kalonensis sp. nov. differs from L. melicus by having a significantly larger body size (Wilcoxon post-hoc Z= -3.9, p<0.001), and greater length between eye and tympanum (Wilcoxon post-hoc Z= -3.0, p=0.003). L. kalonensis sp. nov. differs from L. pyrrhops by having a significantly smaller body size (Wilcoxon post-hoc Z=3.7, p<0.001), smaller relative tympanum size (Wilcoxon post-hoc Z=2.7, p=0.006), smaller relative distance between eye and tympanum (Wilcoxon post-hoc Z=2.2, p=0.025) and smaller relative eye width (Wilcoxon post-hoc Z=3.5, p=0.001). L. kalonensis sp. nov. differs from L. ardens sp. nov. by having a significantly greater body size (Wilcoxon post-hoc Z=4.7, p<0.001). L. kalonensis sp. nov. differs from L. pallidus sp. nov. by having a significantly greater body size (Wilcoxon post-hoc Z=3.0, p=0.002), smaller relative tympanum diameter (Wilcoxon post-hoc Z= -3.1, p=0.002), black supratympanic line in most specimens (versus no black supratypmanic line in L. pallidus sp. nov) and smooth skin texture (versus tuberculate in L. kalonensis sp. nov). L. kalonensis sp. nov. differs from L. maculosus sp. nov. by having a significantly greater body size (Wilcoxon post-hoc Z= -2.7, p=0.007). L. kalonensis sp. nov. differs from L. tadungensis sp. nov. by having a significantly greater body size (Wilcoxon post-hoc Z= -3.3, p=0.001), and greater relative tibia length (Wilcoxon post-hoc Z=-3.5, p=0.001). See Table 4 and Fig. 4 .

Although based on a single call recording, the male advertisement call of L. kalonensis sp. nov. differs from all members of the L. applebyi group with the exception of L. ardens sp. nov. In particular, the species differs from L. applebyi in length of introductory note and dominant frequency; from L. bidoupensis in call duration, presence of a distinct introductory note and dominant frequency (although similar); from L. melicus in dominant frequency; from L. pyrrhops by dominant frequency; from L. pallidus sp. nov. by average call duration, average number of pulses in the introductory note and average note repetition rate; from L. maculosus sp. nov. by average call duration, number of notes per call, and having a distinct introductory note; from L. tadungensis sp. nov. by average call duration, and average duration of introductory note. See Table 7 and Figs. 5–6 .

Leptolalax kalonensis sp. nov. differs from all species within the L. applebyi group by>5.2% divergence at the 16S gene fragment examined. Interspecific variation in four L. kalonensis sp. nov. collected from up to 43 km apart was 0.0–0.6%.

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 4. Morphometric variation and differentiation among adult male frogs in the Leptolalax applebyi group. Boxplots of (A) SVL, (B) relative tibia length (TIB / SVL), (C) relative pectoral gland size (PEC / SVL) and (D) relative tibia length (TIB / SVL) of adult males in each molecular lineage. For all boxplots, horizontal lines within each box represent the median and boxes encompass the 75 th and 25 th quartiles.

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 11. Leptolalax pallidus sp. nov. in life (A) male holotype UNS 0 0 510, (B) male paratype AMS R 177657 (C) male paratype UNS 0 0 512, (D) ventral surface male paratype UNS 0 0 512.

FIGURE 12. Leptolalax kalonensis sp. nov. in life (A) male holotype IEBR A. 2014.15, (B) male paratype AMNH A 191770, (C) male paratype AMNH A 191770, (D) paratype (registration number not recorded).