A new species of Leptolalax (Anura: Megophryidae) from central Vietnam
Author
Rowley, Jodi J. L.
Author
Trung, Cao Tien
text
Zootaxa
2009
2198
51
60
journal article
10.5281/zenodo.189550
61a00500-771b-4656-83c9-eff9b3627d9f
1175-5326
189550
Leptolalax applebyi
sp. nov.
Holotype
: AMS R171703, an adult male, calling in leaf litter,
2 m
from steep, narrow, rocky stream in Song Thanh Proposed Nature Reserve, Phouc Son district, Quang Nam Province,
Vietnam
(
15.27394 º N
,
107.76015 º E
,
1402 m
;
Figure 1
). Collected at 18:15 h on
23 July
, 2007 by the authors.
Paratypes
: AMS R 171704–171706 adult males from
type
locality (
Figure 1
), collected between 18:16– 18:30 h on
23 July
, 2007. All males were calling. AMS R 171707, one adult female collected at 19:00 h, on
24 July
, 2007, from
15.26253 º N
,
107.75759 º E
,
1312 m
. All specimens were found
1–2 m
from steep, narrow, rocky streams in evergreen forest.
Etymology
: specific epithet is a patronym honouring Robert Appleby, an investor in biodiversity conservation and scientific capacity building in Asia.
Diagnosis
: Assigned to the genus
Leptolalax
on the basis of the following: small size, the presence of an elevated thenar tubercle not continuous to the thumb, chest glands present but not forming teats, vomerine teeth absent, anterior tip of snout with vertical white bar (Dubois 1980;
Lathrop
et al
. 1998
).
Leptolalax applebyi
is distinguished from its congeners by a combination of (1) body size (
19.6–20.8 mm
for five adult males;
21.7 mm
for single adult female), (2) uniformly smooth dorsum lacking tubercles, (3) dark brown dorsal surface lacking distinct patterns and dark brownish pink ventral surface with white speckling (4) an absence of webbing and dermal fringes on fingers, (5) slight basal webbing and no dermal fringes on toes (6) short tibia (TIB:SVL 0.466–0.480), and (7) unique advertisement call consisting of 4–5 notes with a dominant frequency of 3962.1–4306.6 Hz, repeated at a rate of approximately 9 notes per second.
FIGURE 1.
Type locality of
Leptolalax applebyi
sp. nov.
(black circle), central Vietnam.
Description of
holotype
: Head longer than wide; snout rounded or truncate in profile, projecting slightly over lower jaw; nostril closer to tip of snout than eye; canthi rostralis rounded, constricted; lores sloping, concave; vertical pupil; diameter of eye less than length of snout; tympanum distinct, round, diameter smaller than that of the eye; anterioventral three-quaters of tympanic rim slightly elevated relative to skin of temporal region; vomerine teeth absent; pineal ocellus absent; vocal sac openings absent; tongue large, broad, and weakly notched posteriorly; weak supratympanic ridge running from eye towards axilla. Tips of fingers rounded, slightly enlarged; relative finger lengths I<II=IV<III; nuptial pad absent; subarticular tubercles absent; a large, round inner palmar tubercle distinctly separated from small, laterally compressed outer palmar tubercle; no finger webbing or lateral fringes. Tips of toes like fingers; relative toe length I<II<V<III<IV; subarticular tubercles absent, replaced by dermal ridges, distinct on second, third and fourth toes; small, oval inner metatarsal tubercle pronounced, outer metatarsal tubercle absent; webbing basal, confined to very base of toes; no lateral fringes. Tibia short and stout, width approximately one-third of length; tibiotarsal articulation reaches anterior corner of eye. Skin on dorsal and ventral surfaces smooth, only eyelid with low, indistinct tubercles; pectoral gland small, indistinct, circular; femoral gland distinct, small white, on posteroventral surface of thigh, closer to knee than to vent; small gland above axilla; no ventrolateral glandular ridge.
FIGURE 2.
(A) Male holotype of
L. applebyi
sp. nov.
in life (AMS R 171703), and (B) ventral view of male holotype and paratypes of
L. applebyi
sp. nov.
in life (AMS R 171703–171706, L to R).
Colour of
holotype
in life:
Dorsal surface dark brown with indistinct, diffuse darker brown patch between axillae; vertical darker brown bars on upper lip, indistinct lighter vertical stripes at tip of snout and under eyes; no interorbital bar; black line along canthus rostralis, through eye, and continuing along supratympanic ridge, encompassing most of tympanum, terminating above axilla; transverse darker bars on dorsal surface of limbs; large, black blotch on posterior flank anterior to sacrum and two smaller black spots on lateral flank; ventral surface of elbow and upper arm without dark bars, indistinct paler colouration on elbow; fingers with indistinct transverse barring; ventral surface dark brownish pink, with white speckling concentrated on belly, but also on throat, ventral surfaces of arms, tibio-tarsus and feet; fine white speckling extends to ventrolateral surface of belly and on lower margins of head, with a single distinct and slightly larger white spot just posterior to tympanum; ventral margin of throat bearing row of larger white spots. Macroglands white. Iris coppery gold, with minute, black reticulations.
FIGURE 3.
(A) Dorsal view, (B) ventral view, and (C) lateral view of head of preserved holotype (AMS R 171703) of
L. applebyi
sp. nov.
, (D) ventral surface of right hand of preserved male paratype of
L. applebyi
sp. nov.
(AMS R171705), and (E) lateral view of preserved female paratype of
L. applebyi
sp. nov.
(AMS R 171707). Scale bar = 2 mm.
FIGURE 4.
Advertisement call of
L. applebyi
sp. nov.
(holotype AMS R 171703) recorded at ambient air temperature of 21.5º C. (A) a 3 s waveform of relative amplitude, (B) corresponding 3 s spectrogram, (C) expanded, 0.27 s waveform and (D) corresponding spectrogram for same call.
Colour of
holotype
in preservative:
Dark brown dorsal surface. Ventral surface pale brown with white speckling and white macroglands. Colours faded.
Measurements
:
Holotype
: SVL 19.6, HDL 7.4, HDW 6.6, SNT 3.0, EYE 2.0, IOD 2.6, TMP: 1.1, TEY 0.7, TIB 9.2, weight
0.8g
Variation
: Specimens vary in dorsal colouration, from uniformly coloured dark brown (AMS R 171706) to weakly mottled (AMS R 171704–5). Dark barring on limbs may be indistinct and diffuse (AMS R 171706). Female (AMS R 171707) pale brown with diffuse darker chevrons on dorsum, above axilla. Paler vertical stripes at tip of snout and under eyes vary from indistinct (AMS R 171706) to distinct (AMS R 171704–5), most distinct in the single female (AMS R 171707). Ventral surface of chest and belly may be white with dark speckling in places, as opposed to all dark with white speckling. Female (AMS R 171707) has slightly paler throat. Elbows of female (AMS R 171707) and one male (AMS R 171705) are distinctly paler. Colouration on dorsal surface of head between the snout and eyes may be slightly paler. Iris colour varies from uniform gold to uniform reddish copper. Black spots on lateral flank variable in number (1–4 spots), size and shape. Female (AMS R 171707) has black spot on left knee. Tibiotarsal articulation reaches between anterior corner of eye and nostril. In life, males weighed
0.8–0.9g
. Female, with distinct follicles present in ovary, weighed 1.0 g in life. Measurements of the
type
series are shown in table 1.
Advertisement call
: Call descriptions are based on the calls of the
holotype
and a non-vouchered individual, both taken at 21.5ºC ambient temperature. Calls consisted of 4–5 notes, repeated at a rate of approximately 9 per second, with each note consisting of between one and five distinct pulses (Table 2,
Figures 4
A, C). There was little frequency modulation, with the dominant frequency between 3962.1–4306.6 Hz (
Figures 4
B, D), and harmonics at approximately 7752 Hz. Pulse duration was between 2–7 ms. To the human ear, the call of
L. applebyi
sounds like a faint, rapid rasping, similar to an orthopteran. The calls of
L. applebyi
and
L. tuberosus
differ considerably in structure and frequency (Rowley & Cao, unpublished data).
TABLE 1
. Measurements (mm) of adult
Leptolalax applebyi
,
sp. nov.
Abbreviations defined in text.
Males Female R171703 R171704 R171705 R171706 R171707
Ecology:
All specimens were found at the headwaters of rocky streams in medium montane forest (evergreen forest between
1200–1500m
;
Tordoff
et al.
2003
). Streams were steep, narrow (<
2 m
wide) and had little water flow. Despite intensive surveys,
L. applebyi
was never heard or observed below
1300 m
elevation. Male
L. applebyi
were found calling from under leaf litter, always approximately
2 m
from the stream.
Leptolalax applebyi
was found in sympatry with
L. tuberosus
.
Leptolalax tuberosus
was more widely distributed in terms of elevation, with individuals collected between
863–1401 m
, and was almost always found greater than
5 m
distance from streams. The stomach contents of AMS R171707 included remains of a small cockroach (order Blattaria).
| SVL 19.6 |
20.7 |
20.8 |
20.8 |
21.7 |
| HDL 7.4 |
7.8 |
7.7 |
7.6 |
8.2 |
| HDW 6.6 |
7.3 |
7.3 |
7.2 |
7.4 |
| SNT 3.0 |
3.4 |
3.0 |
3.2 |
3.8 |
| EYE 2.0 |
2.4 |
2.3 |
2.4 |
2.7 |
| IOD 2.6 |
2.8 |
3.1 |
2.8 |
2.9 |
| TMP 1.1 |
1.4 |
1.6 |
1.5 |
1.6 |
| TEY 0.7 |
1.0 |
0.9 |
0.6 |
0.9 |
| TIB 9.2 |
9.7 |
10.0 |
9.7 |
10.4 |
| HDL:HDW 1.11 |
1.06 |
1.05 |
1.05 |
1.1 |
| HDL:SVL 0.38 |
0.38 |
0.37 |
0.36 |
0.38 |
| TIB:SVL 0.47 |
0.47 |
0.48 |
0.47 |
0.48 |
|
TABLE 2.
Measurements of advertisement are given as means (and ranges).
|
call parameters for
Leptolalax
|
applebyi
sp. nov.
at 21.5ºC.
|
Parameter |
values |
| Recording |
AMS R 171003* |
non-vouchered |
| Number of calls |
6 |
7 |
| Number of notes |
24 |
34 |
| Call duration (ms) |
332 (280–358) |
405 (340–441) |
| Intercall interval (ms) |
245 (226–287) |
287 (234–413) |
| Notes/call |
4 |
4.8 (4–5) |
| Note duration (ms) |
16.6 (8–32) |
14.3 (4–31) |
| Internote interval (ms) |
86.7 (48–140) |
83.7 (38–113) |
| Pulses/note |
3.29 (2–4) |
2.52 (1–5) |
| Note repetition rate (notes/s) |
9.0 (8.4–10.7) |
9.3 (8.6–11.2) |
| Dominant frequency (Hz) |
3962.1 |
4222.9 (3962.1–4306.6) |
*
holotype
Conservation status
: The five
type
specimens are the only known representatives of the new species. Given the available information, we suggest the species should be considered Data Deficient following IUCN’s Red List categories (
IUCN 2001
). Being known from only two localities approximately
1.3 km
apart, its extent of occurrence is unknown but probably more widespread. The known habitat of
L. applebyi
falls within a protected area and is remote and steep enough that immediate deforestation risk is likely low. The habitat of
L. applebyi
is also contiguous with similar areas of habitat in the central Truong Son landscape (
Tordoff
et al
. 2003
), including Ngoc Linh Nature Reserve in Kon Tum Province to the south, and
Laos
in the west, but areas above
1200 m
elevation compose only 8.5% of existing forest in the Truong Son landscape and are patchily distributed (
Tordoff
et al
. 2003
).
Comparisons
:
Leptolalax applebyi
is distinguished from all other described
Leptolalax
species by a combination of (1) body size (
19.6–20.8 mm
for five adult males;
21.7 mm
for single adult female), (2) uniformly smooth dorsum lacking tubercles, (3) dark brown dorsal surface lacking distinct patterns and dark brownish pink ventral surface with white speckling (4) an absence of webbing and dermal fringes on fingers, (5) slight basal webbing and no dermal fringes on toes, (6) short tibia (TIB:SVL 0.466–0.480), and (7) unique advertisement call consisting of 4–5 notes with a dominant frequency of 3962.1–4306.6 Hz, repeated at a rate of approximately 9 notes per second.
Leptolalax applebyi
is one of the smallest species in the genus. Two species of
Leptolalax
have overlapping male adult body sizes;
L. pluvialis
, known only from northern
Vietnam
at
21.3–22.3 mm
, and the recently described
Leptolalax kecil
from the Malay Peninsula, at
19.3–20.5 mm
. Similar body sizes have been reported for
L. alpinis
(24.0–26.4),
L. heteropus
(24.0–
33 mm
),
L. liui
(23.0–
28.7 mm
) and
L. tuberosus
(
24.4–29.5 mm
). All other species have considerably larger male body sizes (
L. arayai
29.6 mm
;
L. bouretti
27.2–36.2 mm
;
L. dringi
28.7–30.3 mm
;
L. fulignosus
28.2–30.0 mm;
L. gracilis
31–39 mm
;
L. hamidi
28.7– 31.3 mm
;
L. kajangensis
34–35 mm
;
L. lateralis
26.9–28.3 mm
;
L. maurus
26.1 mm
;
L. melanolectus
26.6– 28.8 mm
;
L. nahangensis
40.8 mm
;
L. oshanensis
26.6–30.7 mm
;
L. pelodytoides
37 mm
;
L. pictus
up to
36 mm
;
L. solus
30–35 mm
;
L. sungi
48.3–52.7 mm
;
L. ventripunctatus
25.5–28.0 mm).
The single female specimen of
L. applebyi
(
21.7 mm
) does not fall within the range of female body sizes reported in the genus to date (
L. alpinis
32.1 mm
;
L. bouretti
42.0–45.0 mm;
L. dringi
37.5 mm
;
L. gracilis
40–41 mm
;
L. hamidi
36.1–42.8;
L. kecil
25.0 mm,
L. lateralis
36 mm
;
L. liui
23.1–28.1 mm
;
L. maurus
31.8 mm
;
L. melanolectus
32.7 mm
;
L. oshanensis
31.6 mm
;
L. pictus
up to
47 mm
;
L. sungi
56.7–58.9 mm
;
L. tuberosus
30.2 mm
).
The skin texture and colouration of
L. applebyi
differs from all previously described
Leptolalax
species. In terms of skin texture, only
L. applebyi
,
L. pluvialis
,
L. heteropus
,
L. pictus
and
L. kajangensis
have a smooth dorsum lacking tubercles or dorsal ridges. Of these species,
L. applebyi
is the only species with a dark brown dorsal surface lacking distinct dorsal patterns (
L. heteropus
and
L. pictus
have extensive, distinct dorsal markings or patches,
L. pluvialis
has distinct black interorbital markings and
L. kajangensis
has almost black dorsal surfaces with minute pale spots). Additionally, most
Leptolalax
species lacking a smooth dorsum also differ from
L. applebyi
in terms of dorsal colour and pattern (
L gracilis
and
L. hamidi
have extensive, distinct dorsal markings or patches,
L. arayai
,
L. fulignosus
,
L. kecil
,
L. lateralis
,
L. melanoleucus
,
L. nahangensis
,
L. oshanensis
and
L. sungi
have distinct black interorbital markings,
L. maurus
has almost black dorsal surfaces and
L. tuberosus
has a sandy dorsum with an olive brown hatching pattern).
The dark brownish pink ventral surface with white speckling of
L. applebyi
is also distinctly different from other species in the genus (
L. alpinis
,
L. arayai
,
L. bouretti
,
L. dringi
,
L. fulignosus
,
L. gracilis
,
L. hamidi
,
L. lateralis
,
L. liui
,
L. nahangensis
,
L. oshanensis
,
L. pelodytoides
,
L. pictus
,
L. solus
,
L. sungi
and
L. tuberosus
have entirely or mostly white or pale grey venters;
L. pluvialis
has a grey venter with dark grey marbling, uniform pale grey throat with speckling around the border and large whitish grey pectoral glands;
L. melanolectus
and
L. ventripunctatus
display large patches of distinct black and white marbling,
L. heteropus
has a grey venter, speckled with black;
L. maurus
has a black or dark grey brown venter, with indistinct small light areas, and
L. kecil
has a uniformly dark venter with large, dark orange pectoral glands).
In lacking webbing and dermal fringes on fingers and having only slight basal webbing and no dermal fringes on toes,
L. applebyi
is distinguished further from
L. alpinis
,
L. bouretti
,
L. dringi
,
L. fulignosus
,
L. hamidi
,
L. heteropus
,
L. kecil
,
L. liui
,
L. pelodytoides
,
L. pluvalis
,
L. solus
and
L. sungi
, all of which have dermal fringes or extensive webbing.
The relative tibia length of
L. applebyi
(TIB:SVL 0.47–0.48) distinguishes it from
L. kucil
(males 0.56– 0.58)
L. pluvialis
(0.52–0.56)
L. pelodytoides
(0.56),
L. arayai
(0.62), and
L. kajangensis
(0.42).
The advertisement call of
L. applebyi
also differs from the twelve
Leptolalax
species with described calls;
L. arayai
,
L. dringi
,
L. fuliginous
,
L. gracilis
,
L. hamidi
,
L. heteropus
,
L. kecil
,
L. melanoleucus
,
L. pelodytoides
,
L. pictus
and
L. oshanensis
,
L. solus
. Whereas the advertisement calls of
L. gracilis
,
L. heteropus
,
L. kecil
,
L. pelodytoides
,
and
L. solus
overlap with
L. applebyi
in terms of number of notes per call, compared to
L. applebyi
, the calls of
L. gracilis
,
L. heteropus
and
L. solus
have much lower dominant frequencies (2540–3200Hz) and
L. pelodytoides
has higher dominant frequencies (6350–8100Hz). The advertisement call of
L. kecil
has both a lower dominant frequency, a lower number of pulses per note, and higher intercall interval compared to
L. applebyi
.