Litoria nullicedens, Kraus, 2018

Kraus, Fred, 2018, Taxonomy of Litoria graminea (Anura: Hylidae), with descriptions of two closely related new species, Zootaxa 4457 (2), pp. 264-284 : 277-281

Litoria nullicedens , sp. nov.

Figs. 3B , 6A , 7

Holotype. BPBM 18440 (field no. FK 8151), adult male, obtained from a local collector at Dorobisoro , 550 m, 9.4625° S, 147.9218° E (GPS datum AUS 66), Central Province, Papua New Guinea, 8 October 2003.

Diagnosis. Litoria nullicedens sp. nov. may be distinguished from all congeners in its unique combination of the following characters: large size (adult male SV = 75.1 mm, mass = 24.0 g); moderately long leg (TL/SV = 0.53); relatively narrow snout (EN/IN = 1.12); relatively narrow head (HW/SV =0.34); fully webbed hands; absence of parotoid glands; small, round nuptial pads occupying an area approximately equal to one-quarter area of first finger disc; dorsal color bright green; absence of a white labial stripe; iris reticulated black and dark brown; pale portion of sclera external to its black margin with the cornea wide (6–7 times width of this black margin); upper half of nictitating membrane with a dark marginal band and heavily reticulated with pigment throughout; and sides, abdomen, and webbing of hands and feet bright orange-red.

Comparisons with other species. Litoria nullicedens sp. nov. is a member of the Litoria graminea species complex, differing from all Papuan Litoria not of this complex in the combination of large body size, bright-green dorsal coloration, fully webbed hands, and absence of enlarged parotoid glands. The four known members of the L. graminea complex invite closer comparison ( Table 2).

From L. graminea , L. nullicedens sp. nov. differs in having a narrower head (HW/SV = 0.36–0.40 in L. graminea ), dark-brown iris heavily flecked with black (vs. tan stippled with black punctations), upper half of nictitating membrane heavily reticulated with pigment throughout (vs. single band of dark pigment along the upper margin), sides and abdomen bright orange-red (vs. orange), and webbing of hands and feet bright orange-red (vs. orange).

From L. sauroni , L. nullicedens sp. nov. differs in its larger size (adult male SV = 64.6–70.8 mm in L. sauroni ), in having a marginally shorter leg (TL/SV = 0.54–0.60 in L. sauroni ), smaller nuptial pad (vs. pad one-half size of first finger disc in L. sauroni ), iris dark brown heavily flecked with black (vs. red or dark orange flecked with black), nictitating membrane with dense pattern of zig-zag lines (vs. sparser pattern of smaller spots, Fig. 6 ), tympanum without horseshoe-shaped area of translucent skin, sides and abdomen bright orange-red (vs. purpleblue, orange, or yellow), and webbing of hands and feet bright orange-red (vs. orange or yellow).

From L. huntorum , L. nullicedens sp. nov. differs in its larger size (adult male SV = 57.9–60.4 mm in L. huntorum ), single (vs. double) nuptial pad, dark-brown iris heavily flecked with black (vs. tan minutely stippled with black in L. huntorum ), bright orange-red markings on the sides, webbing, and hidden surfaces of the limbs (vs. orange-yellow in L. huntorum ); and in lacking a white labial stripe that extends to the eye (vs. extending posterior to eye in L. huntorum ).

From L. pallidofemora sp. nov., L. nullicedens sp. nov. differs in having a narrower head (HW/SV = 0.36–0.39 in L. pallidofemora sp. nov.); narrower snout (EN/IN = 0.99–1.04 in L. pallidofemora sp. nov.); nuptial pad small and round (vs. large and triangular or with two pads); dark-brown iris heavily flecked with black (vs. tan minutely stippled with black in L. pallidofemora sp. nov.); upper half of nictitating membrane heavily reticulated with dark pigment (vs. clear with a dark upper margin in L. pallidofemora sp. nov.); pale portion of sclera external to the black junction with the cornea wide (vs. 0–2 times width of black margin in L. pallidofemora sp. nov.); dorsal surfaces of thighs bright green (vs. yellow or yellow-green in L. pallidofemora sp. nov.); bright orange-red markings on the sides, webbing, and hidden surfaces of the limbs (vs. yellow or orange in L. pallidofemora sp. nov.); and in lacking a white labial stripe that extends to the eye (vs. extending to rictus in L. pallidofemora sp. nov.).

Description of holotype. An adult male. Head moderately wide (HW/SV = 0.34), barely wider than long (HL/ SV = 0.33, HL/HW = 0.97); loreal region oblique and shallowly concave; canthus rostralis concave, rounded; nostrils oriented laterally, closer to tip of snout than to eyes; internarial distance less than distance from external naris to eye (EN/IN = 1.12, IN/SV = 0.080, EN/SV = 0.089); snout slightly sloping, almost truncate, when viewed from the side, broadly rounded when viewed from above ( Fig. 7A ); eyes moderate (EY/SV = 0.10), not protuberant, eyelid less than half width of interorbital distance; tympanic ring distinct and raised but top margin just covered by supratympanic skin fold, horizontal diameter two-thirds width of eye (TY/EY = 0.68) ( Fig. 7B ).

Skin of dorsal surfaces smooth, with many narrow, shallow creases; these grooves better developed and reticulating laterally and around vent; ventral surfaces of body and thighs coarsely granular, less so on chin and under arms, smooth under shanks. A dermal ridge extends along the outer surface of each forearm and along each foot from the heel to T5. Peritoneum white.

Fingers fully webbed and reaching discs between F3 and F4; fully webbed between F2 and F3, reaching disc of F2 but falling slightly short of disc of F3; half webbed between F1 and F2, with webbing reaching penultimate tubercle of each ( Fig. 7C ); relative lengths 3> 4> 2> 1. Tips of all fingers flattened into discs bearing circummarginal grooves; discs approximately 1.5 times wider than penultimate phalanges on F2–F4 but only slightly wider than penultimate phalanx on F1; single subarticular tubercle present at base of penultimate phalanx on F2 and F3, but subarticular tubercles doubled on F1 and F4; thick inner and low outer metacarpal tubercles present. Nuptial pad on F1 of brown dermal asperities forming a small circle (right) or crescent (left) occupying an area approximately equal to one-quarter that of the disc of F1. Toes entirely webbed, webbing reaching to bases of all discs ( Fig. 7D ); relative lengths 4> 5> 3> 2> 1; tips flattened into discs with circum-marginal grooves; discs approximately 1.5 times width of penultimate phalanges; inner metatarsal tubercle prominent, outer barely evident. Hind legs moderately long (TL/SV = 0.53).

Vomeropalatines with two patches of teeth (approximately six on each side) between internal nares. Vocal slits and sac present.

In preservative, dorsal ground color uniform light blue, as are tops of thighs, shanks, feet, forearms, F4, and T5; blue field also present at base of webbing between T4 and T5. Rear of thighs and tops of F3 and T4 stippled with gray, with slight gray stippling also present distally on F2 and T3. Entire venter, upper arms, and remainder of webbing uniformly white. White stripe on dermal ridge of foot extends from heel to near tip of T5. Lower jaw white from symphysis to anterior margin of eye. Margins of eyelids and external nares white. Palpebral membrane clear with dark upper margin and heavily marked with pattern of crooked lines and spots ( Fig. 6A ), these darker anteriorly and dorsally, turning to white posteriorly and ventrally. Iris brown with large black flecks scattered throughout. Sclera white, with a narrow black margin where it contacts cornea; white area of sclera between cornea and eyelid approximately 6–7 times width of this black rim.

Measurements (in mm). —SV = 75.1, TL = 39.5, EN = 6.7, IN = 6.0, SN = 11.8, TY = 5.3, EY = 7.7, HW = 25.7, HL = 25.0, mass = 24.0g.

Color in life. From notes taken in the field: “Bright green above with pale blue rim around the eyes. Sides and webbing and rear and front of thighs red-orange. Venter and under legs pale orange; chin yellow-green. Dermal ridge on forearms and tarsi green-yellow. Mouth lining blue-green; bones white.” It is readily seen from color photographs of the animal ( Fig. 3B ) that the iris is brown heavily flecked with black and that the white on the lower jaw extends posteriorly only as far as the anterior to middle of the eye.

Ecological notes. No information is available other than that the specimen came from foothill rainforest at approximately 600 m elevation.

Etymology. The name is an invariant compound adjective derived from combining the Latin first-person present participle “cedo”, meaning “I yield”, and the dative of “nullus”, meaning “none” (hence, “I yield to none”), in recognition of the striking color pattern of the species among Papuan frogs.

Range. Known only from the type locality in the southwestern foothills of Mt. Obree , Central Province, Papua New Guinea ( Fig. 1 , triangle).

Figures

FIGURE 1. Map of Papua New Guinea showing the boundaries of former British New Guinea (area south of solid black line) and localities for the five members of the Litoria graminea complex, with localities mentioned in the text identified by name. Filled squares = Litoria graminea, northernmost of which is the type locality for L. dux; stars = L. sauroni; open hexagons = L. huntorum; open circles = L. pallidofemora sp. nov., the southernmost of which is the type locality; filled triangle = L. nullicedens sp. nov. Note that L. pallidofemora sp. nov. and L. sauroni are sympatric at two localities.

FIGURE 3. Portraits in life of (A) holotype of L. pallidofemora sp. nov. (BPBM 22440), Musgrave River, Central Province, and (B) holotype of L. nullicedens sp. nov. (BPBM 18440), Dorobisoro, Central Province, showing diagnostic color-pattern elements that distinguish each.

FIGURE 6. Nictitating membranes of right eyes of (A) Litoria nullicedens sp. nov., BPBM 18440, and (B) Litoria sauroni, BPBM 35101, showing diagnostically different patterns of pigmentation, which is denser and composed of larger, more wormlike markings in the former.

FIGURE 7. Views of A) top of head, B) side of head, C) right hand, and D) right foot of holotype (BPBM 18440) of Litoria nullicedens sp. nov. Scale bar = 1 cm.