Lepidodactylus laticinctus, Kraus & Vahtera & Weijola, 2023

Kraus, Fred, Vahtera, Varpu & Weijola, Valter, 2023, A new species of Lepidodactylus (Squamata: Gekkonidae) from Umboi Island, Papua New Guinea, Zootaxa 5296 (4), pp. 525-539 : 530-533

Lepidodactylus laticinctus sp. nov.

Figs. 2 , 3

Holotype.— UMMZ 249264 (field tag FK 18122), mature female, collected by V. Weijola at Lablab, 5.7207°S, 148.0668°E, sea level, Umboi Island, Morobe Province, Papua New Guinea, 2 April 2018.

Paratypes.—Same data as holotype ( UMMZ 249263 ), and same data as holotype except collected 19 April 2018 ( UMMZ 249265 ) .

Diagnosis.—A fairly large (adult female SVL 49–49.5 mm) species of Lepidodactylus having a subcylindrical tail without a lateral fringe of enlarged scales, 38–41 enlarged scales of pore-bearing series extending to distal ends of thighs, 2 divided subterminal lamellae on T4 , 9–12 T4 lamellae, 8–9 T1 lamellae, rather short toes ( T4 L/SVL = 0.086 –0.088), lamellae occupying slightly more than half of toes ( T4 lamellaeL/ T4 L = 0.53–0.60), fairly wide toes ( T4 W/ T4 L = 0.36–0.40) with moderate webbing ( T3 T4 webL/ T4 L = 0.16–0.21), dorsum in life pale gray with five wide darker gray-brown bands between axilla and tail base, and tail banded with yellow and brown or pale and darker brown.

Comparisons with other species.—The subcylindrical tail without a lateral fringe of enlarged scales and the two divided subterminal scansors under the toes place Lepidodactylus laticinctus sp. nov. in Brown and Parker’s (1977) phenetic Group II. Hence, it is distinguished from Papuan species belonging to Group I ( L. aignanus , L. magnus , L. mutahi , L. pumilis , L. sacrolineatus , and L. zweifeli ) by having two divided subterminal lamellae (vs. none in members of Group I); and it is distinguished from Papuan species belonging to Group III ( L. lugubris , L. pantai , and L. woodfordi ) in having a subcylindrical (vs. flattened) tail lacking (vs. having) a lateral fringe of scales and in having the terminal scansors entire on all toes (vs. divided on T2–T5). From other Papuan members of Group II, L. laticinctus sp. nov. differs as follows: from L. dialeukos , L. kwasnickae , L. mitchelli , L. novaeguineae , L. orientalis , and L. pulcher in having 38–41 enlarged scales of the pore-bearing series (vs. 14 in L. dialeukos , 12–15 in L. kwasnickae , 12–14 in L. mitchelli , 12–17 in L. novaeguineae , 19–33 in L. orientalis , and 18–20 in L. pulcher ) that extend to the knee (vs. being limited to the precloacal region in the other six species); and from L. pollostos and L. shebae in its larger size (SVL 49–49.5 mm vs. 35.5 mm in the sole specimen [adult male] of L. pollostos and 36 mm in the sole specimen [adult male] of L. shebae ) and greater number of enlarged scales of the pore-bearing series (38–41 vs. 17 in L. pollostos and ~ 34 in L. shebae ), and dorsal ground color pale gray (vs. reddish brown in L. pollostos and L. shebae ).

Among Papuan Group II species, L. laticinctus sp. nov. is most similar to L. guppyi , from which it differs in having a lower number of divided T4 lamellae (uniformly 2 vs. 2–4, mean 2.8, mode 3 in L. guppyi ), fewer average number of T1 and T4 lamellae, fewer enlarged femoral/precloacal scales, shorter toes, smaller eye, shorter snout, and shorter temporal region ( Table 1 ). Lepidodactylus laticinctus sp. nov. is most distinctive from L. guppyi in its color pattern, differing in its dorsal pattern of five wide gray-brown bands between the axilla and tail base on a palegray ground color (vs. typically with six or more narrow and poorly defined brown bands on a brown ground color, or with no bands at all, in L. guppyi , Fig. 2 ) and in having a distinct, pale postocular stripe (vs. stripe absent or only vaguely developed in L. guppyi ). It is also quite different genetically from L. guppyi (see below).

Description of holotype.—A mature female of medium size (SVL = 49.5 mm, TrL = 24.0 mm); cut anterolaterally on right trunk, liver removed. Head relatively long (HL/SVL = 0.21) and wide (HW/HL = 0.81), distinct from neck. Loreal region slightly inflated; no distinct canthus rostralis. Top of snout, area between nares, and area posterior to nares shallowly concave. Snout tapered and rounded at tip, relatively long (SN/HL = 0.43), significantly longer than eye diameter (SN/EY = 1.8). Eye of modest size (EY/HL = 0.24, EY/EN = 0.74); pupil vertical, constricted into series of four lobes; anterior supraciliaries slightly larger than adjacent granules, posterior ones subequal to adjacent granules. Ear opening small (Ear/HL = 0.078), compressed, oriented vertically; distance between ear and eye larger than eye diameter (EE/EY = 1.6). Rostral twice as wide (2.0 mm) as high (1.0 mm), highest just medial to nares, lower between these points; length 0.35 mm. Supranasals separated by three internasals. Rostral in contact with first supralabials, two supranasals, and three internasals. External nares circular; each bordered by rostral, two supranasals, first supralabial, and one (L) or two (R) postnasals. Mental virtually an equilateral triangle, 0.9 mm wide. Mental bordered posteriorly by two enlarged postmentals and in point contact with one genial; enlarged postmentals bordered posteriorly by subequal scales that progressively decrease in size posteriorly to join granular chin scales. First five infralabials bordered below by somewhat enlarged scales, subequal in size to postmentals; remaining scales below infralabials of approximately same size as throat scales, which decrease in size medially. Supralabials to mid-orbital position eight on each side, to angle of jaw 11 (R) and 12 (L). Infralabials 11 on each side.

Body of rather narrow habitus (TrL/SVL = 0.48), slightly depressed dorsoventrally. Dorsal scales on head, body, limbs, and throat tiny, juxtaposed granules, larger on sides and snout; tubercles absent. Ventral scales larger, flat and smooth, subimbricate, gradually decreasing in size laterally to become granular.

Enlarged precloacal/femoral scales in single series of 41 scales extending almost to knees; thigh scales anterior to this row larger than those posterior. Enlarged scales form a pubic patch between the precloacal series and vent; no tiny scales between the precloacal series and the pubic patch; eight scales in a row between apex of enlarged precloacal series and vent. Scales on palms and soles rounded, flattened, smooth, subimbricate.

Fore- and hindlimbs relatively small but well-developed (FA/SVL = 0.09, CS/SVL = 0.11). Digits well-developed ( Fig. 3A, B ), widely dilated throughout their length (T4W/T4L = 0.42), all but first fingers and toes with recurved claws; clawed phalanges laterally compressed, free above and extending slightly beyond terminal lamellae. Subdigital lamellae narrow and smooth, all undivided except penultimate and antepenultimate lamellae divided on F2–F5 and T2–T5 ( Fig. 3A, B ), all lamellae undivided on F1 and T1; lamellae extend for only slightly more than half length of each toe (T4 scansor L/T4L = 0.56). Lamellae of manus 7–9–10–10–9 on right, 8–9–10– 9–8 on left; of pes 9–9–9–9–9 on right, 8–9–9–9–8 on left. Relative lengths of digits on manus and pes I <II <V <III <IV. Webbing present between all digits; toes approximately one-fifth webbed or less (T3T4webL/T4L = 0.21, T4T5webL/T4L = 0.14).

Tail complete, subcylindrical, almost as long as body (TL/SVL = 0.95), relatively narrow (TW/SVL = 0.076); lateral margins without skin flanges or spines ( Fig. 3C ). Scales of tail small, square, flat, smooth, subimbricate, larger ventrally than dorsally. Cloacal sacs not swollen ( Fig. 3D ), with small external orifices situated near lateral margins of vent; single slightly enlarged, blunt postcloacal spur on each side of tailbase; midventral scales of sac hexagonal, slightly larger than those ventrolaterally.

Color in preservative: Dorsal ground color brown with five wide, dark-brown bands between axilla and tail base ( Fig. 3C ), these darker laterally than medially, imparting impression of lateral dark-brown blotches; one more vaguely outlined dark-brown band on neck, and vague dark-brown mottling on nape; tail with pale-brown ground and eight dark-brown bands, the last covering tail tip. Head medium brown, darker on snout; labials stippled with brown on a dirty-white ground. Venter dirty white; chin and throat speckled with brown scales; chest, abdomen, and undersides of limbs with few brown scales joining to form flecks laterally ( Fig. 3D ). Palmar and plantar surfaces dirty white with few pale-brown scales forming scattered flecks. Iris chocolate brown.

Measurements (in mm).—SVL = 49.5, TrL = 24.0, TL = 47.0, TW = 3.9, FA = 4.4, CS = 5.5, HL = 10.3, HW = 8.3, Ear = 0.8, EE = 4.1, EY = 2.5, SN = 4.4, EN = 3.4, IN = 2.1, T4L = 4.3, T4W = 1.8, T4 scansor L = 2.4, T3T4webL = 0.9, T4T5webL = 0.6, mass = 1.85 g.

Variation.—The two paratypes are very similar to the holotype in most respects. UMMZ 249263 has two small, calcified endolymphatic sacs, six dark-brown tail bands, and a hint of a pale postocular stripe; UMMZ 249265 has two large, calcified endolymphatic sacs, eight dark-brown tail bands, and a hint of a pale postocular stripe. It further differs in having the central dark-brown band closer to, and not evenly spaced from, its neighboring dark-brown bands; the head and neck are darker than in the holotype; and the chin and throat are only finely and sparsely stippled with brown.

Measurements of paratypes (in mm).—(UMMZ 249263): SVL = 49.0, TrL = 24.0, TL = 41.0, TW = 3.7, FA = 5.1, CS = 5.6, HL = 10.8, HW = 8.5, Ear = 0.6, EE = 4.1, EY = 2.5, SN = 4.5, EN = 3.1, IN = 2.0, T4L = 4.3, T4W = 1.7, T4 scansor L = 2.3, T3T4webL = 0.7, T4T5webL = 0.6, mass = 1.80 g. (UMMZ 249265): SVL = 49.0, TrL = 24.5, TL = 39.0, TW = 3.5, FA = 4.7, CS = 5.7, HL = 10.6, HW = 8.3, Ear = 0.6, EE = 4.0, EY = 2.4, SN = 4.5, EN = 3.5, IN = 2.2, T4L = 4.2, T4W = 1.5, T4 scansor L = 2.5, T3T4webL = 0.9, T4T5webL = 0.7, mass = 2.05 g.

Color in life.—Field notes for UMMZ 249263 ( Fig. 2A ) state “Dorsum brown gray with brown bands; venter pale yellow; tail pale yellow with brown bands. Iris coppery brown.” The holotype was very similar ( Fig. 2B ) except that the venter was pale gray. UMMZ 249265 ( Fig. 2C ) differed somewhat more: “Pale brown with darker-brown mottling, vaguely arrayed in bands, which are clearer on the tail. Venter very pale yellow, almost white, unflecked. Iris brown.” Photos of all specimens clearly show a pale postocular stripe.

Genetics.—Pairwise distances ( Table 2 ) between the samples of Lepidodactylus laticinctus sp. nov. and the Lepidodactylus sp. specimen from New Britain (SAMA R64666) are 16.2–16.4% for ND2 ( Table 2 ) and 1% for PDC ( Table 3 ); differences between the new species and the L. guppyi / L. vanuatuensis samples are 13.9–16.2% for ND2 and 0.8% for PDC.

TNT analysis resulted in 573 MP trees of length 2265 steps. In the majority consensus tree ( Fig. 4 ), the sole specimen of Lepidodactylus sp. from New Britain is resolved as sister to L. laticinctus sp. nov. but with no branch support.Together they form the sister clade (JF = 94) to a polytomy including all L. guppyi and L. vanuatuensis specimens (JF = 86). Likelihood analysis ( Fig. 5 ) and Bayesian analysis (not shown) produced a result largely congruent to that of parsimony with the difference that the New Britain specimen was resolved as sister (BS = 51, pp= 1) to all remaining representatives of the L. guppyi clade, being followed first by L. laticinctus sp. nov. (BS= 99, pp= 1) and then by the L. guppyi / L. vanuatuensis clade (BS = 97).

Etymology.—The name is a masculine Latin combinatorial adjective from latus, meaning “broad”, and cinctum, meaning “band”, in recognition of the distinctive dorsal pattern of this species.

Range.—Known only from the type locality ( Fig. 1 ), but likely to occur across the coastal areas of Umboi Island and possibly more widely throughout the lowlands of that island. We did not find this species on surveys of coastal and lowland forests of nearby Sakar and Tolokiwa islands.

Ecology.—All three animals were found active at night ~ 50–200 cm above ground on a single large, isolated Casuarina tree on a sandy beach only a few meters from the ocean in a village area of moderately high human use (walking trails, boat launch, nearby residences). There is considerable coastal and secondary forest all along the eastern shore of Umboi Island. We searched extensively throughout these forests for one week and failed to find additional individuals, so the ecology of this species needs to be better delimited. All specimens have red mites lodged between the digital lamellae, with UMMZ 249265 being especially heavily infested in these regions.

Figures

FIGURE 1. Map of Melanesia, showing the localities sampled for molecular analysis for members of the Lepidodactylus guppyi Group: L. laticinctus sp. nov. (red), L. guppyi (green), L. vanuatensis (yellow), and Lepidodactylus sp. New Britain (purple).

FIGURE 2. Portraits in life of (A) paratype of Lepidodactylus laticinctus sp. nov. (UMMZ 249263), Umboi Is., PNG; (B) holotype of L. laticinctus sp. nov. (UMMZ 249264), Umboi Is., PNG; (C) paratype of L. laticinctus sp. nov. (UMMZ 249265), Umboi Is., PNG; (D); Lepidodactylus sp. (SAMA R64666), New Britain, PNG; (E, F) L. guppyi, Guadalcanal Is., Solomon Islands, (G) L. guppyi, Malaupaina Is., Solomon Islands, and (H) L. guppyi, Ngela Is., Solomon Islands. Photos (A, B) F. Kraus, (C) V. Weijola, (D) S. Richards, and (E–H) M. McCoy.

FIGURE 4. The majority consensus of 573 most-parsimonious trees of the Lepidodactylus guppyi Group for concatenated dataset with jackknife resampling values> 50% shown on the nodes. Branch lengths represent the number of optimized character-state changes.

FIGURE 5. Maximum-likelihood tree of the Lepidodactylus guppyi Group for concatenated dataset with bootstrap values>50% shown for each node rooted with Gekko vittatus as outgroup. Scale bar corresponds to the mean number of nucleotide substitutions per site.

FIGURE3. (A) Palmarview of righthand, (B)plantar view of rightfoot,(C) dorsum, and(D) venter ofholotype ofLepidodactylus laticinctus sp. nov. (UMMZ 249264), Umboi Is. Scale bars are 5 mm.