Limnonectes selatan, Matsui & Belabut & Ahmad, 2014

Matsui, Masafumi, Belabut, Daicus M. & Ahmad, Norhayati, 2014, Two new species of fanged frogs from Peninsular Malaysia (Anura: Dicroglossidae), Zootaxa 3881 (1), pp. 75-93 : 86-89

Limnonectes selatan sp. nov.

Synonymy: Rana kuhlii: Boulenger, 1912, p. 229 (part); Taylor, 1962, p. 408 (part); Berry, 1975, p. 71 (part). Rana kuhli: Inger, 1966, p. 196 (part).

Holotype. UKMHC 529 (former KUHE 53961 ), an adult male from Genting Highlands , State of Pahang, Malaysia (3 o 24' N, 101 o 46' E, 1069 m a.s.l.: Fig. 10 ), collected on 22 February 2011 by Masafumi Matsui.

Paratypes. KUHE 53379 (one adult female) , KUHE 53380 (one young female) collected on 13 September 2009 by Daicus M. Belabut and Kanto Nishikawa, and KUHE 53962 , 53963 (two adult males) , KUHE 53964–53970 , 53990 (eight adult females) , KUHE 54010 , 54011 (two unsexed young) , KUHE 53955 (one just metamorphosed young) collected from 22 to 23 February 2011 by Masafumi Matsui, Daicus M. Belabut, Kanto Nishikawa, and Norihiro Kuraishi, all from the type locality .

Referred specimens. KUHE 15106 , 15108 , 35567 (three unsexed young) from Ulu Gombak , State of Selangor, Malaysia (3 o 19' N, 101 o 45' E, ca. 200 m a.s.l.), collected on 9 December 1992 by Masafumi Matsui . KUHE 49515 (one lot of larvae, including KUHE 2011001 and 2011004 in Table 1 ), data same as the holotype .

Etymology. The specific epithet selatan is a Malay word denoting south, alluding to the more southerlyrestricted distribution within the Peninsular Malaysia of the new species compared to L. utara .

Diagnosis. Generic assignment of the new species is same as for L. utara described above. A medium-sized L. kuhlii -like species, with adult SVL 52–54 mm in males, 61–73 mm in females; males with relatively longer head than females; tibia densely covered by warts dorsally; toe webbing full, with very shallow excision between toes; first finger usually slightly longer than second, and nuptial pad present on first finger of males; differentiated from L. utara sp. nov. in having more rugose dorsal skin, more densely arranged circum-cloacal warts, dark dorsal spots usually isolated from other spots, and the presence of large dark blotches on the rear of the thigh.

Description of holotype (measurements in mm). SVL 53.9; habitus stocky ( Figs. 3B , 4C,D ); head enlarged, slightly longer (HL 24.8, 46.0% SVL) than broad (HW 23.1, 42.9%); snout obtusely pointed, obtuse in profile, projecting beyond lower jaw; eye length (EL 7.8, 14.5% SVL) shorter than snout length (SL 8.8, 16.3% SVL); canthus rounded; lore sloping, concave; nostril dorsolateral, on canthus, closer to tip of snout than to eye; internarial distance (IND 5.1, 9.5% SVL) slightly smaller than interorbital distance (IOD 5.3, 9.8% SVL), latter wider than upper eyelid (UEW 4.4, 8.2% SVL); pineal spot visible; tympanic annulus slightly visible through skin; vomerine teeth in oblique groups, between and behind line connecting anterior rims of choanae, groups separated from one another by one-third length of one group and from choana by one-third length of one group; lower jaw with a pair of tooth-like projections near symphysis, more than twice depth of mandible at base of projections; tongue oval, deeply notched posteriorly, without papillae; vocal sac and vocal slits absent.

Forelimb heavy, relatively short (FLL 28.5, 52.9% SVL); fingers moderately slender; finger length formula: II <I <IV <III, first finger slightly longer than second, length of first (6.7, 12.4% SVL, measured from distal edge of inner palmar tubercle) shorter than length of eye; fourth finger much longer than second; tips of fingers bluntly rounded, forming small pads without circummarginal grooves; no webs between fingers; inner palmar tubercle moderate (2.6, 4.8% SVL), oval, not elevated; middle palmar tubercle oval, smaller than inner palmar tubercle, not contacting outer or inner palmar tubercles; outer palmar tubercle slightly smaller than middle tubercle; proximal subarticular tubercles round and elevated; distal subarticular tubercles low, flat and indistinct; no supernumerary metacarpal tubercles; narrow, but distinct flaps of skin along both edges of second and third fingers.

Hindlimb heavy, relatively short (HLL 80.5, 149.4% SVL) about 2.8 times length of forelimb; tibia short (TL 25.1, 46.6% SVL), heels not overlapping when limbs are held at right angles to body; tibiotarsal articulation of adpressed limb reaching to posterior corner of eye; foot (FL 26.5, 49.2% SVL) longer than tibia; toe length formula I <II <V <III <IV; tips of toes expanded into small, round, elevated pads lacking grooves (disk diameter of fourth toe, 4TDW 0.8, 1.5% SVL); all toes webbed to base of disks ( Fig. 5D ); webbing formula: I 0 – 0 II 0 – 0 III 0 – 0 IV 0 – 0 V; a distinct, movable flap of skin on outer edge of fifth toe and on inner edge of first toe; subarticular tubercles oval and distinct; an elongate inner metatarsal tubercle, length (IMTL 3.5, 6.5% SVL), less than half length of first toe (1TOEL 8.4, 15.6% SVL); no outer metatarsal tubercle.

Dorsum anteriorly rugose, without warts, posteriorly with low ridges radiating from scattered, low warts; top of snout without tubercles; eyelid covered with small warts and wrinkles with medial, longitudinal ridge formed by fused warts; transverse fold between posterior margins of eyes absent; strong, supratympanic fold from eye to above axilla; side of trunk wrinkled and scattered with tubercles; circum-cloacal warts small, densely and widely distributed anteriorly, but increasing size posteriorly to end at dorso-ventral border of thigh ( Fig. 6B ); dorsal surface of thigh smooth on proximal two-thirds and scattered with small, low warts tipped with translucent spinules on distal one-third, continuing to tibia; tibia dorsally covered with numerous large and small round warts each tipped with a large whitish cone surrounded by clusters of much smaller, whitish asperities ( Fig. 5C ); tarsus less densely covered by similar warts dorsolaterally; tarsus with thick dermal ridge extending proximally from metatarsal tubercle; throat and chest weakly rugose, abdomen smooth; a distinct creamy tinge, with minute white asperities, forming a nuptial pad covering medial surface of first finger from its base to level of subarticular tubercle, sharply set off from remainder of skin on first finger.

Color. In life, dorsum brown scattered with darker spots ( Figs. 3B , 4C ); head with a narrow light band anterior to dark interorbital bar; blackish brown stripe on canthus rostralis; side of head pale brown; oblique blackish brown temporal stripe on and along supratympanic fold beginning behind eye reaching inguinal area; lips barred with dark brown; dark brown spot on anterior side of upper arm; limbs marked dorsally with dark-brown crossbars; dorsal and ventral border of posterior thigh heavily marked with large dark brown spots ( Fig. 6B ); throat mottled with pale gray; abdomen immaculate cream ( Fig. 4D ); ventral surfaces of hand and foot dark brown ( Fig. 5D ). In preservative, the dorsal coloration has become darker, but otherwise no obvious change in color or pattern has occurred.

Variation. Individual variation in size and body proportions is given in Table 3 . In all individuals, postorbital light-colored bar was absent, and well-developed warts on the tibia and weak spots or dots on chin were present. Temporal stripe was usually narrow (in 92% of individuals), and was mere a trace in some (8%). Dorsal spots were usually few and weak (85%) and were absent in some (15%). A dark stripe on the upper arm was usually absent (85%), and was weak or disjunct in some (15%). Dorsal warts were usually present only partially (85%), and some had very few warts (15%). The first finger was usually longer than second (67%), but in some individuals they were subequal (17%), or the second was longer than first (17%).

Eggs and tadpoles. Eggs and tadpoles from Genting Highlands were examined. The diameter of eight oviducal eggs from a female (KUHE 53379) ranged from 2.10–2.59 (mean±1SD = 2.37±0.18) mm. The animal hemisphere of egg is dark brown and the vegetal hemisphere is pale yellow in color. Each egg is enclosed with two transparent jelly layers.

Tadpoles hatch at stage ( Gosner 1960) 24 (total length = 10.7–12.2 [mean±1SD = 11.4±0.7] mm, head-body length = 3.7–3.8 [3.8±0.1] mm, n = 5) with rudimentary outer gills on left side, and can swim freely. They retain large amount of yolk and trace of suckers, and have a complete, but still unprotruded, eye under transparent skin and opened nostril, but the mouth is a mere depression and limb buds are absent.

A total of five older tadpoles of stage 40 (total length=44.9–47.6 [mean±1SD = 46.4±1.2] mm, head-body length = 15.3–16.7 [16.1±0.5] mm) were closely examined. Head and body oval, slightly flattened above and below; width maximum at level of spiracle, 61–69 (median = 63)% of head-body length; depth 64–75 (median = 69)% of head-body width; snout rounded dorsally and in profile; eyes dorsolateral, not visible from below, eyeball diameter 11–12 (median = 12)% of head-body length; interorbital distance moderate, 116–136 (median = 136)% of eyeball diameter, less than eye-snout distance; nostril open, dorsolateral, rim not raised, midway between eye and tip of snout; internarial 69–83 (median = 74)% of interorbital. Oral disc anteroventral, emarginate, width 27–33 (median = 30)% of body width ( Fig. 7H ). Marginal papillae on upper labium with wide gap, lateral parts expanded, with eight short papillae in one row at corners, and few submarginal papillae; lower labium with continuous single row of wide, short and long papillae, and irregularly arranged submarginal papillae; labial teeth row formula 2(2)/ 3(1) or 2(2)/3(1–2), second anterior row rudimentary on each side, third posterior row about one-fourth length of second posterior row; serrated jaw sheaths forming wide arches with narrow black margins, upper jaw sheath with weak medial convexity. Spiracle sinistral, on left side, directed posterodorsally, tube fused to body wall, free portion distinct, length about half width of opening; snout-spiracle distance 43–57 (median = 54)% of head-body length. Vent tube dextral, attached to ventral fin. Tail lanceolate, both margins weakly convex, tapering gradually to tip; tail length 178–198 (median = 194)% of head-body length, maximum height 25–28 (median = 27)% of tail length; caudal muscle taller than either fin in proximal half of tail; origin of dorsal fin far posterior to end of body, dorsal fin higher than ventral fin except near tip of tail. Neuromasts of dorsal, infranaso-orbital, lateral, mental, pregular, postgular, postspiracle, and supranaso-orbital lines traceable. No glands present. In life, light brown dorsally with weak darker bands; dark band at junction of tail and body, continuing to base of caudal muscle. Fin and lateral caudal muscle speckled with large, dark transverse bands ( Fig. 8 ). Two juveniles just after metamorphosis are 17.7 and 20.2 mm in SVL, with large conical warts on dorsal surface of tibia.

Call characteristics. A call was recorded at the type locality at air and water temperature of 20.0°C and 19.8°C, respectively, at 18:50 h on 22 February 2011 by N. Kuraishi. However, the recording was poor quality because of heavy background noises of the stream, close to which the male stayed. The call consisted of a series of four notes and lasted 3.3 s. Each note was emitted at a gap (between the beginnings of two successive notes) of 0.94−1.24 (mean±1SD = 1.05±0.16) s and lasted for 0.12−0.14 (0.13 ± 0.01) s ( Fig. 9 ). Pulse structure of each note could not be analyzed because of the poor quality of recording. The dominant frequency was ca. 0.5 kHz. Frequency modulation was observed within a note, and the frequency at the beginning 0.7–0.8 kHz decreased towards the end of the note to ca. 0.4 kHz. The frequency difference between the beginning and the end of the note was 0.3–0.4 kHz.

Comparisons. Limnonectes selatan sp. nov. differs from the other L. kuhlii -like species in the same manner as L. utara sp. nov., by its uniquely developed tibial warts. It is very similar to L. utara sp. nov., but differs from it as noted above.

Range. Peninsular Malaysia: Genting Highlands, State of Pahang (1069 m a.s.l.); Ulu Gombak, State of Selangor (ca. 200 m a.s.l.). Records of Rana kuhlii from Genting Simpah, Selanger ( Berry 1975) and Hills of Selangor and Negri (sic.) Sembilan ( Boulenger, 1912) are thought to represent this species (see Discussion). Known localities range in altitude from 200–1069 m a.s.l.

Natural history: The type series of L. selatan was found at a swampy area in a valley, where there are seepages leading to a slowly moving small stream (width <2m) in the shade of shrubs and grasses in a well-grown secondary forest. In late February, occasional calls of males, females in ovulating condition, recently laid eggs, and larvae of various degree of development, including metamorphosed juveniles, were observed at the type locality. Among dead leaves on the bottom of shallow, slowly flowing water, eggs were laid scattered and tadpoles were found hiding themselves. Thus the breeding season seems last long at this locality unless the larval duration is long, which is unlikely. Amphibian species at the type locality were Megophrys longipes , Limnonectes blythii , L. tweediei , L. plicatellus , Odorrana hosii , Philautus petersi , and P. vermiculatus .

Figures

FIGURE 3. Dorsolateral views of male holotypes of Limnonectes utara sp. nov. (UKMHC 528) from Larut Hill (A) and L. selatan sp. nov. (UKMHC 529) from Genting Highlands (B).

FIGURE 4. Dorsal (A, C) and ventral (B, D) views of anesthetized male holotypes of Limnonectes utara sp. nov. (UKMHC 528) from Larut Hill (A, B) and L. selatan sp. nov. (UKMHC 529) from Genting Highlands (C, D) Scale bar = 10 mm.

FIGURE 5. Ventral views of hand (A) and foot (B) of male holotype of Limnonectes utara sp. nov. (UKMHC 528) from Larut Hill, and preaxial view of hand (C) and ventral view of foot (D) of male holotype of L. selatan sp. nov. (UKMHC 529) from Genting Highlands. In anesthetized state, scale bar = 10 mm.

FIGURE 6. Posterior views of left thigh of preserved male holotypes of Limnonectes utara sp. nov. (UKMHC 528) from Larut Hill (A) and L. selatan sp. nov. (UKMHC 529) from Genting Highlands (B), showing circum-cloacal warts and dark blotches along dorso-ventral border. Not to scale.

FIGURE 7. Lateral (A, D), dorsal (B, E), and ventral (C, F) views, and oral disk (G, H) of larvae putatively assigned to Limnonectes utara sp. nov. from Larut Hill (A, B, C, G: KUHE 49514, Stage 36, total length = 39.9 mm) and confirmed as Limnonectes selatan sp. nov. from Genting Highlands (D, E, F, H: KUHE 49515, Stage 38, total length = 45.4 mm) after preservation. Scale bar for A–F= 10 mm. G, H=not to scale.

FIGURE 8. Dorsal (A), lateral (B), and ventral (C) views of larval Limnonectes selatan sp. nov. from Genting Highlands (KUHE 49515, Stage 40, total length = 46.6 mm) in life. Scale bar = 5 mm.

FIGURE 9. Sonagram showing an advertisement call of a male Limnonectes selatan sp. nov. from Genting Highlands, recorded at an air temperature of 20.0°C.

FIGURE 10. Schematic map of the Malay Peninsula, illustrating the five mountain ranges (from west to east: A, Banjaran Bintang; B, Banjaran Titiwangsa; C, Banjaran Benom; D, Banjaran Gunung Tahan; E, Banjaran Timur), the type localities (filled triangles) of Limnonectes utara sp. nov. (Larut Hill) and L. selatan sp. nov. (Genting Highlands), and known localities of either of the two or unidentified species (dark circles: 1, Hulu Terengganu; 2, Ulu Gombak; 3, Gunung Bubu; 4, Gunung Lawit; 5, Endau Rompin). Hatching indicates areas 300 m a.s.l. and above in elevation.