Lepidodactylus aignanus, Kraus, 2019

Kraus, Fred, 2019, New species of Lepidodactylus (Squamata: Gekkonidae) from New Guinea and adjacent islands, Zootaxa 4651 (2), pp. 305-329 : 307-309

Lepidodactylus aignanus sp. nov.

Fig. 1A, C

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Holotype. BPBM 17229 (field tag FK 6989), mature female, obtained by F. Kraus from local collector at Liak, 10.6594°S, 152.6941°E, near sea level, Misima Island , Milne Bay Province, Papua New Guinea, 13 January 2003.

Diagnosis. A small (adult SVL 37.5 mm) species of Lepidodactylus having a subcylindrical tail without a lateral fringe of enlarged scales; all subterminal scansors entire; 17 enlarged scales of pore-bearing series limited to precloacal region; 11–12 T4 lamellae, 7–9 T1 lamellae; fairly wide toes (T4W/T4L = 0.33); toes approximately onequarter webbed (T3T4webL/T4L = 0.26); dorsum with several irregular dark-brown saddles, and many pale lateral and dorsolateral round spots, especially concentrated from forearm to eye.

Comparisons with other species. The subcylindrical tail without a lateral fringe of enlarged scales and the series of undivided scansors under all toes place Lepidodactylus aignanus sp. nov. in Brown and Parker’s (1977) Group I. Lepidodactylus aignanus sp. nov. differs from other Melanesian members of this group as follows: from L. flaviocularis Brown, McCoy & Rodda , L. magnus Brown & Parker , L. mutahi Brown & Parker , and L. pumilus in having 17 enlarged precloacal scales (versus 26–50 enlarged precloacal/femoral scales in the other species) limited to the precloacal region (extending far onto the thighs in the other species); from L. browni Pernetta & Black and L. orientalis Brown & Parker in having 17 enlarged precloacal scales (versus 19–27 in L. orientalis and 22–39 in L. browni ), toes with more webbing (T3T4webL/T4L = 0.26 versus 0.11–0.16 in L. browni and 0.10–0.14 in L. orientalis , Fig. 1C ), and dorsum with many pale lateral and dorsolateral round spots ( Fig. 1A ), especially concentrated from forearm to eye (versus absent in L. browni and L. orientalis , or with few vague dorsolateral spots behind forearm in one specimen of L. browni ).

Description of holotype. A mature female, with right-lateral incision. Animal small (SVL = 37.5 mm, TrL = 18.3 mm). Head relatively long (HL/SVL = 0.23) and wide (HW/HL = 0.80), distinct from neck. Loreal region slightly inflated; no distinct canthus rostralis. Interorbital region and top of snout concave. Snout tapered and rounded at tip, relatively long (SN/HL = 0.41), longer than eye diameter (SN/EY = 1.6). Eye relatively large (EY/HL = 0.26, EY/EN = 0.76); pupil vertical, constricted into series of four lobes; supraciliaries subequal in size to adjacent granules. Ear opening small (Ear/HL = 0.070), somewhat compressed, oriented diagonally from posterodorsal to anteroventral; distance between ear and eye larger than eye diameter (EE/EY = 1.4). Rostral wider (1.8 mm) than high (0.8 mm), highest just medial to nares, lower between these points; length 0.4 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 postnasal. Mental shallowly triangular, slightly longer (0.65 mm) than wide (0.60 mm). Mental bordered posteriorly by two enlarged postmentals, these bordered posteriorly by two rows of slightly enlarged scales prior to granular chin scales. Infralabials bordered by enlarged scales that gradually decrease in size posteriorly. Supralabials to mid-orbital position nine on each side; to angle of jaw 13 on right, 12 on left. Infralabials 11 on each side.

Body of modest habitus (TrL/SVL = 0.49), slightly depressed. Dorsal scales on head, body, and limbs tiny, juxtaposed granules; tubercles absent. Ventral scales flat and smooth; those on throat smaller and juxtaposed; those on abdomen larger and subimbricate, gradually decreasing in size laterally and on chin to become granular.

Enlarged precloacal scales 17, in a single short series; no enlarged scales on thighs. Enlarged scales form a pubic patch between the precloacal series and vent; no row of tiny scales between the precloacal series and either side of the pubic patch; ten scales in a row between apex of enlarged precloacal series and vent. Scales on palms and soles rounded, smooth.

Fore- and hindlimbs relatively small (FA/SVL = 0.083, CS/SVL = 0.12). Digits well-developed, moderately dilated throughout their length (T4W/T4L = 0.33), all but first fingers and toes with recurved claws; clawed phalanges laterally compressed, free above and extending slightly beyond terminal scansors. Subdigital scansors narrow and smooth, all undivided except for three terminal scansors divided on left third toe; lamellae extend for more than half length of each toe (T4 scansor L/T4L = 0.62, Fig. 1C ). Lamellae of manus 7–9–11–11 –9 on right, 8–8–10–11 –8 on left; of pes 8–10–11–12 –10 on right, 9– 9–10–11–10 on left. Relative lengths of digits on manus and pes I <II <V <III <IV. Webbing present between all digits except first and second on both manus and pes; toes approximately one-quarter webbed (T3T4webL/T4L = 0.26, Fig. 1C )

Tail missing except for 5.5 mm behind vent, relatively wide (TW/SVL = 0.10), with slight constriction approximately 2.5 mm behind vent; lateral margins without skin flanges or spines. Scales of tail remnant small, flat, smooth, subimbricate ventrally; granular dorsally; no enlarged postcloacal spurs on sides of tailbase.

Color in preservative: Dorsal ground color medium brown with small, irregular, vague, darker-brown markings scattered dorsally and laterally, these coalescing into a short scapular line on each side ( Fig. 1A ). A lateral and dorsolateral row of pale-straw spots on each side, extending from in front of forearm insertion to just before groin (lateral row) and to base of tail (dorsolateral row). Other, more vaguely defined pale spots scattered about behind head. Venter pale straw with scattered brown punctations concentrated toward sides. Under limbs, palms, and soles same but with all scales having brown punctations. Labials also pale straw with brown punctations. Iris dark brown, pupil pale gray.

Measurements (in mm). SVL = 37.5, TrL = 18.3, TW = 3.8, FA = 3.1, CS = 4.6, HL = 8.6, HW = 6.9, Ear = 0.6, EE = 3.0, EY = 2.2, SN = 3.5, EN = 2.9, IN = 1.8, T4L = 3.9, T4W = 1.3, T4lamellaeL = 2.4, T3T4webL = 1.0.

Etymology. The name is a masculine adjective referring to the type locality of Misima Island, whose former name was St. Aignan Island.

Range. Known only from the type locality, but no doubt ranges across the lower elevations of Misima Island ( Fig. 2 ).

Ecology. The area around Liak is mixed gardens with a fringe of coastal trees. Common trees in the area include Artocarpus altilis , Calophyllum inophyllum , Cocos nucifera , and Musa spp. It is uncertain how close to shore the specimen was collected, but L. lugubris was obtained at the same location and often dominates shoreline communities, so L. aignanus sp. nov. may occur somewhat inland from that. It remains unknown as well what the upper elevation of this species might be.

Remarks. This species was included in the phylogeny of Oliver et al. (2018a) as a member of the L. orientalis species group. Its sister taxon in that tree was a population of Lepidodactylus from nearby Sudest Island, which is known from only two specimens, has proven difficult to distinguish from L. orientalis based on that small sample, and is not described herein.

Figures

FIGURE 1. Dorsal views of holotypes of (A) Lepidodactylus aignanus sp. nov., BPBM 17229, and (B) L. zweifeli sp. nov., AMNH 105088; right foot of holotypes of (C) Lepidodactylus aignanus sp. nov., BPBM 17229, and (D) L. zweifeli sp. nov., AMNH 105088. Scale = 2 mm.

FIGURE 2. Map of New Guinea and surrounding islands showing type localities for Lepidodactylus aignanus sp. nov. (diamond), L. dialeukos sp. nov. (triangle), L. kwasnickae sp. nov. (square), L. mitchelli sp. nov. (circle), and L. zweifeli sp. nov. (star).