Litoria singadanae, Richards, Stephen J., 2005

Richards, Stephen J., 2005, A new species of treefrog (Anura: Hylidae: Litoria) from the Huon Peninsula, Papua New Guinea, Zootaxa 1052, pp. 29-39 : 30-37

Litoria singadanae sp. nov. ( Figs 1–4 )

Type material: Holotype. SAMA R60172. Adult ɗ; Ridge above Surim Camp (5o52.424’S, 146o42.658’E, 1280 m asl), eastern Finisterre Mountains, Morobe Province, Papua New Guinea. Collected by Greg Setliffe, Markus Manumbor and Kenneth Molem for S. Richards on 5 January 2003.

Paratypes. UP 9968. Adult ɗ; SAMA R60171, adult φ, same details as for holotype except UP 9968 collected 4 January 2003.

Diagnosis. A moderately small (two males 29.0 and 29.1 and a female 34.6 SV), slender Litoria that can be distinguished from all congeners by the following combination of characters: 1) limbs moderately long (TL/SV 0.55–0.60), 2) dorsum in life mottled light and dark green, 3) posterior half of venter orange, 4) snout truncate, canthus rostralis poorly defined, 5) vomerine teeth absent, 6) fingers with extensive fleshy webbing, 7) tympanic membrane transparent with small white flecks.

Description of holotype. Measurements are presented in Table 1 . Adult male with vocal slits and nuptial pads. Moderately slender frog, snout short, truncate, nearly vertical in lateral view, rounded in dorsal view. Canthus rostralis poorly defined, broadly rounded; loreal region steep, slightly concave. Eyes moderately large (EYE/SV 0.11), protruding slightly in dorsal view, pupil horizontal when contracted. Nares much closer to tip of snout than to eyes, directed laterally, not visible in dorsal view. Head slightly wider than long (HW/HL 1.03). Tympanum large and conspicuous (TYM/EYE 0.75), with well­defined annulus that abuts a poorly defined, curved supratympanic fold dorsally. Tympanic membrane transparent except for central connective tissue at attachment of columella, and tiny white flecks ( Fig. 1 ). Tongue broadly cordiform without obvious posterior notch. Vomerine teeth absent. Skin dorsally finely shagreened, throat very slightly granular, chest and abdomen coarsely granular.

Fingers short, relative lengths 3>4>2>1, extensively webbed. Finger webbing thick and fleshy, reaching discs on 2nd and 4th digits, and to mid­way between penultimate subarticular tubercle and disc on 3rd digit with a fleshy fringe continuing to disc. Subarticular tubercles prominent, those on fingers 3 and 4 distinctly bi­lobed ( Fig. 2 ). Discs moderately large (3FP/3FD 0.71) with circum­marginal grooves. A series of pale tubercles along outer edge of forearm. Toes fully webbed except 4th, webbed to penultimate subarticular tubercle; relative lengths 4>5>3>2>1. Subarticular tubercles prominent, penultimate tubercle on 5th toe bilobed. Discs moderately large (4TP/4TD 0.64) with circum­marginal grooves. Limbs long (SV/TL 0.57) with a narrow, slightly crenulated dermal fringe along outer edge of tarsus.

Colour in life mottled pale and darker green dorsally, with scattered white and dark green­brown spots dorsally and on legs. Small white spots concentrated on forearm, thigh and tibia, and in loreal region. A large patch of paler green in shoulder region. Darker green­brown pigmentation occurs 1) between eyes, forming vaguely V­shaped mark in inter­ocular region, 2) in a band extending transversely between dorsal edges of tympana and contacting posterior edge of inter­ocular mark, and 3) in a second broad transverse bar forming an inverted V­shaped mark slightly anterior to mid­point of body and extending on to ventro­lateral surface. A broken band of dark green­brown pigment and several white tubercles along outside of forearm and hand. Lateral surfaces of body, tarsus and outer edge of thigh white with dark green­brown spotting, tarsal fringe white. Spots around upper and lower lip dark green­brown. Additional dark green­brown pigment in narrow ring around vent, and in patches on dorsal and ventral surfaces of tarsus and ventro­lateral surfaces of body. A large patch of white tubercles below vent extends distally onto thighs. Eye very pale brown mottled with darker brown; large brown patch at anterior and posterior edge of iris . Ventrally white with extensive orange colour extending from mid­venter to vent and covering all hidden and ventral surfaces of legs, axilla (extending anteriorly in short narrow band diagonally from axilla towards mid­line of venter), and groin. Throat white with sparse stippling of tiny dark green­brown pigments and intense dark green­brown pigment spots concentrated towards edge of lower jaw and in large irregular patches slightly anterior of angle of jaws. Tympanic membrane transparent except for numerous tiny white flecks and central, dense connective tissue attached to columella, which is pale green. Surface of middle ear (external surface of otic capsule) white. Annulus with patches of dark green pigment. Toes 4–5 and fingers 3–4 green dorsally with white and dark green spots, toes 1–3 and fingers 1–2 white dorsally with scattered clumps of dark green pigmentation

In preservative orange of ventral surfaces and hidden surfaces of limbs has faded completely to cream with a faint pink tinge. Green colour of dorsum has become mottled light and dark grey­blue. Darker dorsal bands have become indistinct. Dark green­brown spots and flecks, particularly those ventrally, have become intense dark blue­black.

Variation. Measurements of the type series are presented in Table 1 . The male paratype is very similar to the holotype in size and body proportions but has a tongue that is distinctly more oval than broadly cordiform. The female is substantially larger than the males, and has the longest limbs of the type series. The difference in body size between the female paratype and the two males is typical of sexual dimorphism within this genus and in other respects the female closely resembles the holotype. The dark green­brown dorsal markings of the paratypes are more prominent than on the holotype and most pronounced in SAMA R60171 ( Fig. 3 ). All three specimens exhibit the striking combination of an orange venter and a transparent tympanum.

Comparison with other species. In its moderate size, green dorsal colour, extensively webbed fingers, and blunt snout, Litoria singadanae sp. nov. shows some resemblance to L. nigropunctata . It differs from that species and all other Australopapuan hylids by having a transparent tympanum revealing a white middle ear that in life contrasts strongly with the green body colour. Among small green Litoria it further differs from L. albolabris by its larger size (males ~ 29 vs 20–22 SV), extensively webbed fingers and absence of vomerine teeth (present in albolabris ; Tyler 1968); from L. mystax by lacking a broad white bar beneath the eye, by having more extensively webbed fingers and lacking vomerine teeth (present in L. mystax ); from L. rubrops by its larger size (males 29.0–29.1 vs 21.4–25.2 SV) and pale brown (vs red) iris ( Kraus & Allison 2004) ; from L. iris , and L. majikthise by lacking violet markings in the axilla and groin; from L. wapogaensis by its mottled green (vs green with yellow spots) dorsum, truncate (vs bluntly rounded) snout and lack of vomerine teeth; from L. chloronota by its orange (vs creamy) postero–ventral surface and pale brown (vs reddish orange) iris ( Menzies 1993) ; from L. contrastens by its mottled (vs uniform green) dorsal colouration, orange venter (vs white; Tyler 1968) and blunt snout (rounded in L. contrastens ); from L. havina in its lack of a rostral spike, and mottled dorsal coloration (uniform green in L. havina ); from L. leucova in its orange ventral and thigh colour (hidden surfaces of thighs pink with yellow spots in L. leucova ; Johnston & Richards 1994); from L. longicrus in its shorter limbs (0.55–0.60 vs 0.62–0.63) and orange venter; from L. mucro in lacking a rostral spike, and from that species and L. ollauro in its orange thigh colour (golden yellow peppered black in L. mucro , blue in L. ollauro ; Menzies 1993, Richards & Iskandar 2001); from L. umarensis by its much larger tympanum (TYM/EYE 0.69–0.75 vs <0.5) and orange (vs brown­black) hidden surfaces of thighs ( Günther 2004); from L. elkeae and other members of the L. gracilenta ‘group’ ( L. gracilenta , L. auae and L. kumae ; Menzies & Tyler 1994), in lacking a pale stripe along the canthus rostralis (present in L. gracilenta group) and its orange ventral colour.

Litoria singadanae sp. nov. is most similar to Litoria verae , a species recently described from Papua Province, Indonesian New Guinea ( Günther 2004). That species shares with L. singadanae a combination of blunt snout, extensively webbed fingers, narrow white crenulated ridge along outer edge of tarsus and foot, and orange colouration ventrally. L. verae is a slightly larger species (males 33.3–35.0, a female 40.8, vs 29–29.1 and 34.6 SV respectively), possesses vomerine teeth (absent in L. singadanae ), has a much smaller tympanum (TYM/EYE 0.44–0.51 vs 0.69–0.75) and has an opaque tympanic membrane (transparent in L. singadanae ).

Natural History. All specimens were collected during the day from a small ridge­top clearing above Surim Camp, at an altitude of 1280 m asl. They were found sitting motionless and extremely well camouflaged against the bark of large tree trunks felled to create a small garden. Vegetation around the garden is lower montane mossy rainforest on steep dissected ridges. No free­standing water occurred anywhere on this ridge or in the near vicinity. The collectors noted that when disturbed the female (SAMA R60171) ‘raised its four legs, exposing the orange colouration in the axilla and groin’. This is the first report of defensive behaviour of this type in a New Guinea hylid frog.

Available data do not permit definitive association of L. singadanae with feeding or reproductive habitats. The female (SAMA R60171) contains large, heavily pigmented eggs suggesting that this species is not a lotic breeder but additional data are required to confirm or discount this hypothesis. The discovery of such a striking new species in a region generally regarded as having a depauperate upland frog fauna suggests that careful documentation of anuran fauna in the extensively forested Saruwaged/Finisterre mountain block may reveal yet more treasures and argues strongly for conservation measures to be undertaken in this spectacular mountain region.

Distribution. Known only from the type locality ( Fig. 4 ).

Etymology. It gives me great pleasure to name this beautiful frog for my good friend and wantok Rose Singadan of the University of Papua New Guinea, who’s unfailing assistance, good humour and brutal corrections of my melanesian pidgin have made my work in Papua New Guinea such a pleasure over the past 14 years.

Figures

FIGURE 1. Lateral view of head of holotype of Litoria singadanae sp. nov. (SAMA R 60172). Scale bar = 5 mm.

FIGURE 2. Palmar and plantar views of holotype of Litoria singadanae sp. nov. (SAMA R 60172). Scale bar = 5 mm.

FIGURE 3. Female paratype (SAMA R 60171) of Litoria singadanae sp. nov. in life.

FIGURE 4. Map of northeastern Papua New Guinea showing type locality (Surim) of Litoria singadanae sp. nov. in central Huon Peninsula.

Tables

TABLE 1. Measurements (mm) of the type series of Litoria singadanae sp. nov.

	SAMA R60172	UP 9968	SAMA R60171
Sex	M	M	F
SV	29.1	29.0	34.6
TL	16.6	16.05	20.8
TL/SV	0.57	0.55	0.6
EN	2.9	2.4	3.6
IN	2.9	2.6	3.4
EN/IN	1	0.92	1.05
HW	9.8	9.2	11.7
HL	9.5	9.5	12.8
HW/HL	1.03	0.97	0.91
EYE	3.2	3.5	3.7
EYE/SV	0.11	0.12	0.11
TYM	2.4	2.4	2.7
TYM/EYE	0.75	0.69	0.73
3FP	1	1	1.4
3FD	1.4	1.5	2.3
3FP/3FD	0.71	0.66	0.60
3FD/SV	0.048	0.051	0.066
4TP	0.9	1	1.6
4TD	1.4	1.4	2
4TP/4TD	0.64	0.71	0.8