Lepidodactylus mitchelli, Kraus, 2019

Kraus, Fred, 2019, New species of Lepidodactylus (Squamata: Gekkonidae) from New Guinea and adjacent islands, Zootaxa 4651 (2), pp. 305-329 : 312-316

Lepidodactylus mitchelli sp. nov.

Fig. 3A, D , 4A

urn:lsid:zoobank.org:act:AFFBA315-F8AA-45D0-933A-EEC2F5BA02CC

Holotype. UMMZ 244058 (field tag FK 17164), mature male, collected by F. Kraus and W. Nemani, Boiaboiawaga Island , 10.2096°S, 150.9059°E, sea level, Milne Bay Province, Papua New Guinea, 20 March 2015.

Paratypes (n=7). Same locality as holotype, collected by F. Kraus and D. Mitchell, 25 May 2002 ( BPBM 15841–47 ) .

Diagnosis. A medium-sized (adult SVL 35–45.5 mm) species of Lepidodactylus having a subcylindrical tail without a lateral fringe of enlarged scales; 12–14 enlarged scales of pore-bearing series limited to precloacal region, 10–13 precloacal pores in males; 13–17 T4 lamellae, 8–11 T1 lamellae, with 2–3 divided subterminal scansors on T4; lamellae occupying most of toes (T4lamellaeL/T4L = 0.84–0.98); fairly wide toes (T4W/T4L = 0.31–0.40) with moderate webbing (T3T4webL/T4L = 0.13–0.23); row of tiny scales between the precloacal series and either side of the pubic patch; dorsum usually with several irregular dark-brown saddles (wide tan vertebral band in one juvenile); and many posteroventral and plantar scales uniformly brown.

Comparisons with other species. The subcylindrical tail without a lateral fringe of enlarged scales and the 2–3 divided subterminal scansors under the toes place Lepidodactylus mitchelli sp. nov. in Brown and Parker’s (1977) Group II. Lepidodactylus mitchelli sp. nov. differs from other Melanesian members of this group as follows: from L. guppyi , L. pulcher , and L. shebae in having fewer enlarged precloacal/femoral scales (12–14 versus 39–52, 18–20, and 34, respectively) and fewer precloacal pores (10–13 versus 39–52, 16, and 32, respectively); it further differs from L. pulcher in its smaller adult size (SVL = 35–45.5 mm versus 40–55 mm in L. pulcher ). The new species is most similar to L. novaeguineae . It differs from that species in having more T4 lamellae (13–17 versus 9–15 in L. novaeguineae ), its color pattern of vague dark-brown saddles ( Fig. 4A , versus many longitudinal dark streaks or dorsolateral series of bold dark-brown blotches in L. novaeguineae ), generally darker venter (heavily peppered with brown in seven of eight specimens versus white with sparse brown punctations in L. novaeguineae , Fig. 3A versus 3C), and in having many posteroventral and plantar scales uniformly brown (versus only with minute black punctations in L. novaeguineae , Fig. 3D versus 3F).

Description of holotype. A mature male of medium size (SVL = 40.5 mm, TrL = 19.5 mm). Head relatively long (HL/SVL = 0.24) and wide (HW/HL = 0.88), distinct from neck. Loreal region slightly inflated; no distinct canthus rostralis. Top of snout, area between nares, and area posterior to nares concave. Snout tapered and rounded at tip, relatively long (SN/HL = 0.44), almost twice eye diameter (SN/EY = 1.9). Eye relatively small (EY/HL = 0.23, EY/ EN = 0.65); pupil vertical, constricted into series of four lobes; supraciliaries slightly larger than adjacent granules. Ear opening small (Ear/HL = 0.073), compressed, oriented diagonally from posterodorsal to anteroventral on right, horizontal on left; distance between ear and eye significantly larger than eye diameter (EE/EY = 1.6). Rostral wider (2.0 mm) than high (0.9 mm), highest just medial to nares, lower between these points; length (0.2 mm); barely visible from above. 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, shorter (0.60 mm) than wide (0.75 mm). Mental bordered posteriorly by two enlarged postmentals, these bordered posteriorly by three rows of enlarged gulars that are followed by smaller granular chin scales. First three infralabials bordered below by somewhat enlarged postmentals; remaining scales below infralabials smaller, only twice size of central throat scales. Supralabials to mid-orbital position nine on each side; to angle of jaw 12 on each side. Infralabials 13 on each side.

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

Enlarged precloacal scales in single series of 12 scales, each bearing a pore; scales on thighs not enlarged. Enlarged scales form a pubic patch between the precloacal series and vent; row of tiny scales between the precloacal series and either side of the pubic patch; eight scales in a row between apex of enlarged precloacal series and vent. Scales on palms and soles rounded, smooth.

Fore- and hindlimbs relatively small but well-developed (FA/SVL = 0.11, CS/SVL = 0.13). Digits well-developed, broadly dilated throughout their length (T4W/T4L = 0.31, Fig. 3D ), all but first fingers and toes with recurved claws; clawed phalanges laterally compressed, free above and extending slightly beyond terminal scansors. Subdigital lamellae narrow and smooth, all digits with 2–3 divided subterminal scansors; lamellae extend for majority of length of each toe (T4 scansor L/T4L = 0.89). Lamellae of manus 9–10–11–13 –9 on right, 9–10–11–13 –10 on left; of pes 8–11–16–16 –11 on right, 10–10–14–15 –8 on left. Relative lengths of digits on manus and pes I <II <V <III <IV. Webbing present between all digits; toes only basally webbed (T3T4webL/T4L = 0.13, Fig. 3D ).

Tail complete, subcylindrical, longer than body (TL/SVL = 1.14 in life), relatively narrow (TW/SVL = 0.096), preserved in recurved position; lateral margins without skin flanges or spines. Scales of tail small, flat, smooth, subimbricate, larger ventrally than dorsally. Cloacal sacs swollen, with small external orifices situated near lateral margins of vent; two enlarged, blunt postcloacal spurs on each side of tailbase; midventral scales of sac only slightly larger than those ventrolaterally.

Color in preservative: Dorsal ground color medium brown with few small, obscure, dark-brown markings dorsally and laterally on body; none on head or neck. Tail darker, with three or four vague darker-brown bands proximally. Venter, palmar, and plantar surfaces pale whitish straw heavily peppered with dark brown ( Fig. 3A ); less stippling on throat; more heavily stippled under tail. Iris dark brown, pupil pale gray.

Measurements (in mm). SVL = 40.5 (43 in life), TrL = 19.5, TL = 49 (in life), TW = 3.9, FA = 4.3, CS = 5.1, HL = 9.6, HW = 8.4, Ear = 0.7, EE = 3.5, EY = 2.2, SN = 4.2, EN = 3.4, IN = 2.1, T4L = 4.5, T4W = 1.4, T4lamellaeL = 4.0, T3T4webL = 0.6, mass (g) = 1.50.

Variation. The enlarged precloacal scales vary from 12–14, and the number of precloacal pores from 10–13. Number of T4 lamellae range from 13–17, and the number of divided subterminal scansors varies from 2–3 and is most often two. Lamellae occupy most of the length of each digit (T4 scansor L/T4L = 0.84–0.98, mean = 0.91). Most specimens have nine supralabials to under the pupil, but two specimens have eight. Toes are relatively wide (T4W/T4L = 0.31–0.40, mean = 0.37) but with only basal webbing (T3T4webL/T4L = 0.13–0.23, mean = 0.18). Otherwise, mensural features show relatively little variation ( Table 1 ).

Dark markings in the paratypes are typically more obscure than in the holotype and are absent in BPBM 15843. All but one adults are well stippled ventrally with dark brown; the exception (BPBM 15844) has very little ventral stippling. The greatest color difference is in the smallest animal (BPBM 15846), an immature male. This specimen has a pale yellow-brown mid-dorsum bordered dorsolaterally on each side by a broken dark-brown stripe that extends from behind head to tail base; it also has a pale venter with little dark-brown stippling, mostly on the sides. The irises of all paratypes are copper colored and heavily veined with dark copper.

Color in life. Field notes for BPBM 15841 recorded that the dorsum was light yellow-brown with dark-brown dusting and crossbands, and the tail was tan with the same crossbands and dusting. The animal was yellow at night. Venter was light yellow anteriorly, purple gray posteriorly, and pale peach on tail, all dusted with dark brown. When photographed during the day, the holotype (UMMZ 244058) was brown with a grayish-brown mid-dorsum, a few small dark-brown markings on the dorsum and sides, and a gray tail with brown crossbands ( Fig. 4A ). Contrary to its dark-brown appearance in preservative, in life this animal had the heavily veined, copper-colored iris seen in all the paratypes ( Fig. 4A ).

Etymology. The name is a genitive honorific for my friend, David Mitchell, who has directed a series of conservation organizations in Milne Bay Province for many years, frequently provided logistical support to my expeditions in that same province, and helped collect part of the type series.

Range. Known only from the type locality, a coral cay island of only 0.072 km 2 that lies 3.6 km off the eastern shore of East Cape, Milne Bay Province ( Fig. 2 ). Presumably this species will be found to occur on other islands in the area, although it is uncertain whether it will be found on either mainland New Guinea or on the larger offshore islands.

Ecology. The holotype was collected in a ca. 3-meter-tall Pandanus during the day; the paratypes were taken on the trunks of Casuarina trees at night. Vegetation in the center of this island is dominated by Pisonia grandis ; the shoreline is dominated by Pandanus , Casuarina , and Cocos ( Fig. 5A ). A new species of nematode of the genus Spauligon Skrjabin, Schikhobalova, & Lagodovskaja was described from the paratypes under the name L. novaeguineae ( Bursey et al. 2005) .

Remarks. This species was referred to as Lepidodactylus novaeguineae in the phylogram of Stubbs et al. (2017, fig. 5) and as Lepidodactylus Boiaboiawaga in the phylogram of Oliver et al. (2018a, fig. 1). Its sister taxon in that latter tree was the following species.

Figures

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).

FIGURE 3. Ventral views of (A) holotype of L. mitchelli sp. nov. (UMMZ 244058), (B) paratype of L. kwasnickae sp. nov. (BPBM 39884), and (C) paratype of L. novaeguineae (AMNH 100210) showing ventral pigmentation differences among these species; scale bars = 5 mm. Ventral views of (D) left foot of holotype of L. mitchelli sp. nov. (UMMZ 244058), (E) left foot of paratype of L. kwasnickae sp. nov. (BPBM 39884), and (F) right foot of paratype of L. novaeguineae (AMNH 100210) showing toe-width and pigmentation differences among these species; scale bars = 2 mm.

FIGURE 4. Portraits of new Lepidodactylus species in life. (A) holotype of L. mitchelli sp. nov. (UMMZ 244058), (B) holo- type of L. kwasnickae sp. nov. (BPBM 39880), (C) paratype of L. kwasnickae sp. nov. (BPBM 39879), and (D) paratype of L. kwasnickae sp. nov. (BPBM 39151).

FIGURE 5. (A) Boiaboiawaga Island, Milne Bay Province, Papua New Guinea, habitat of Lepidodactylus mitchelli sp. nov., photo by D. Mitchell; and (B) interior forest on Woodlark Island, Milne Bay Province, Papua New Guinea, habitat of L. kwas- nickae sp. nov., photo by D. Polhemus.

Tables

TABLE 1. Meristic and mensural data for type series of Lepidodactylus mitchelli sp. nov.. Backslashes distinguish between right and left sides.

Character	UMMZ	BPBM	BPBM	BPBM	BPBM	BPBM	BPBM	BPBM
	244058	15841	15842	15843	15844	15845	15846	15847
Sex	M	F	M	F	M	M	imm M	M
mass (g)	1.50	1.85	2.05	2.15	1.50	1.15	0.85	1.20
SVL	40.5	43.0	42.5	45.5	39.5	35.0	33.0	36.0
TrL	19.5	21.3	19.8	21.1	18.8	17.5	16.4	17.7
TL		42.5	27.5	48.0	36.0	35.5	34.0	39.5
TW	3.9	4.5	4.0	4.4	4.3	3.8	3.4	4.1
CL	5.1	5.3	6.0	5.9	5.4	4.5	4.6	4.8
FL	4.3	5.0	4.3	4.9	4.5	4.0	3.7	4.3
HL	9.6	9.4	10.3	10.5	9.1	8.5	8.0	8.6
HW	8.4	8.5	9.3	9.0	8.3	7.5	6.5	7.7
EY	2.2	2.3	2.4	2.5	2.2	2.0	2.0	2.1
EN	3.4	3.3	3.7	3.7	3.1	2.9	2.8	2.9
IN	2.1	2.2	2.2	2.4	2.2	1.8	1.6	1.9
SN	4.2	4.3	4.8	5.0	3.9	3.7	3.4	3.8
Ear	0.7	0.6	0.8	0.7	0.9	0.7	0.5	0.7
EE	3.5	3.4	3.9	3.7	3.4	3.0	2.9	3.3
T4L	4.50	4.30	4.10	4.50	4.20	3.50	3.40	3.20
T4 width	1.40	1.50	1.65	1.80	1.30	1.40	1.10	1.25
T3T4 web L	0.60	0.70	0.70	0.90	0.60	0.80	0.50	0.60
T4lamellaeL	4.00	4.20	3.60	4.30	3.90	3.10	3.00	2.70
T4 lamellae	15/16	15/17	14/15	17/17	15/17	15/15	14/14	13/14
Divided T4 scansors	3/3	2/3	2/2	2/2	2/2	2/2	2/2	2/2
Enlarged precloacal scales	12	12	13	12	12	13	14	12
Precloacal pores	12		13		10	12	12	10
Rows cloacal scales	8	7	7	6	7	8	10	7
TrunkL/SVL	0.48	0.50	0.47	0.46	0.48	0.50	0.50	0.49
TailL/SVL		0.99	0.65	1.05	0.91	1.01	1.03	1.10
TailW/SVL	0.096	0.10	0.094	0.097	0.11	0.11	0.10	0.11
CrusL/SVL	0.13	0.12	0.14	0.13	0.14	0.13	0.14	0.13
ForearmL/SVL	0.11	0.12	0.10	0.11	0.11	0.11	0.11	0.12
HL/SVL	0.24	0.22	0.24	0.23	0.23	0.24	0.24	0.24
HW/SVL	0.21	0.20	0.22	0.20	0.21	0.21	0.20	0.21
EY/SVL	0.054	0.053	0.056	0.055	0.056	0.057	0.061	0.058
EN/SVL	0.084	0.077	0.087	0.081	0.078	0.083	0.085	0.081
IN/SVL	0.052	0.051	0.052	0.053	0.056	0.051	0.048	0.053
SN/SVL	0.10	0.10	0.11	0.11	0.10	0.11	0.10	0.11
EE/SVL	0.086	0.079	0.092	0.081	0.086	0.086	0.088	0.092
HW/HL	0.88	0.90	0.90	0.86	0.91	0.88	0.81	0.90
EY/EN	0.65	0.70	0.65	0.68	0.71	0.69	0.71	0.90
EN/IN	1.62	1.50	1.68	1.54	1.41	1.61	1.75	1.53
SN/HL	0.44	0.46	0.47	0.48	0.43	0.44	0.43	0.44
IN/EN	0.62	0.67	0.59	0.65	0.71	0.62	0.57	0.66
SN/EY	1.9	1.9	2.0	2.0	1.8	1.9	1.7	1.5
EY/HL	0.23	0.24	0.23	0.24	0.24	0.24	0.25	0.30
EarL/HL	0.073	0.064	0.078	0.067	0.099	0.082	0.063	0.081