Gehyra maculicincta, Kraus, 2024

Kraus, Fred, 2024, New species of Gehyra (Squamata: Gekkonidae) from Papua New Guinea, Zootaxa 5512 (2), pp. 240-271 : 256-262

Gehyra maculicincta sp. nov.

urn:lsid:zoobank.org:act:58AE6703-6880-4651-B23B-13520CDEDE61

Figs. 3C, D , 4C , 9

Gehyra oceanica Goldberg, Bursey & Kraus 2010: 139 [part].

Holotype.— UMMZ 244055 (field tag FK 17096 ), mature male, F. Kraus, collected at Sibonai, Normanby Island , 10.0338° S, 150.9701° E, 5 m a.s.l., Milne Bay Province, Papua New Guinea, 17 March 2015.

Paratypes (n=8).— Same data as holotype except collected 18 March 2015 ( UMMZ 244056–57 ) , and 10.033° S, 150.9771° E, 40 m a.s.l., 25 May 2004 ( BPBM 19771 ) ; Suau, 10.5936° S, 150.0508° E, 100 m a.s.l., Milne Bay Province, Papua New Guinea, 29 March 2017 ( UMMZ 245458 ) ; Opea Island , 10.6034° S, 150.0113° E, 1 m a.s.l., Milne Bay Province, Papua New Guinea, 31 March 2017 ( UMMZ 245459–62 ) .

Diagnosis.—A medium-sized ( SVL of adult males 58.0– 69.5 mm, of adult females 59.5–69 mm) species of Gehyra having entirely undivided subterminal lamellae on all toes; 11–13 T 4 lamellae; 8–11 T 1 lamellae; relatively little webbing between all toes ( T 3– T 4webL/ T 4L = 0.13–0.30, T 4– T 5webL/ T 4L = 0.04–0.19); short snout (SN/HL = 0.44–0.50, EN/HL = 0.35–0.39); wide head ( HW /HL = 0.80–0.94); 32–45 enlarged precloacal/femoral scales; 37– 45 precloacal/femoral pores in a continuous chevron in males; multiple rows of small, subequal subcaudal scales in original tails; tail depressed, flattened when regenerated, lacking lateral serrations; lateral skin fold absent on trunk (n = 3) or small (n = 6); antecubital and popliteal skin folds absent; elongate postmentals; 3–6 scales in posterior contact with postmentals; three postnasals; all postsupranasal scales small, <<50% size of supranasal; dorsal color pattern of bold dark-brown and pale yellow-tan spots arrayed in alternating bands across the dorsum on a medium-brown ground color.

Comparisons with other species.—Among Melanesian Gehyra , G. maculicincta is easily distinguished from G. baliola , G. barea , G. insulensis , G. interstitialis , G. lampei , G. leopoldi , and G. papuana by having undivided (vs. divided) subapical lamellae under the toes. Gehyra maculicincta differs from G. cf. dubia in having more webbing between the digits (vs. absent or only basal in G. cf. dubia ) and a boldly marked dorsum (vs. pale gray in G. cf. dubia ); from G. aquilonia , G. chrysopeleia , G. georgpotthasti , G. marginata , G. membranacruralis , and G. rohan by its much smaller size (up to 70 mm SVL in G. maculicincta vs.> 100 mm in those other species), and in having multiple rows of small subcaudals (vs. single median row of enlarged subcaudals in those other species) in original tails; and from G. serraticauda in its smaller size (90 mm SVL in G. serraticauda ), in having multiple rows of small subcaudals (vs. single median row of enlarged subcaudals G. serraticauda ) in original tails, and in lacking lateral serrations on the tail (vs. present in G. serraticauda ).

Gehyra maculicincta is most similar to G. oceanica , from which it differs in its generally smaller size (up to 70 mm SVL vs. up to 102 mm in G. oceanica ), fewer T 4 lamellae (11–13, mean 12.4 vs. 13–19, mean 15.7 in 157 Polynesian G. oceanica , 15–20, mean 17.7 in 80 Micronesian G. oceanica ); and color pattern of bold pale-tan and dark-brown spots arrayed in bands across the dorsum (vs. dorsum uniform gray, brown, or with small scattered spots but not arrayed in bold bands in G. oceanica ). These scalational differences are most clear in a bivariate plot of numbers of precloacal/femoral pores vs. numbers of T 4 lamellae ( Fig. 8 ).

Description of holotype.—A mature male of medium size ( SVL = 69.5 mm) with a right-lateral incision behind the pectoral region; liver removed. Head relatively long (HL/ SVL = 0.23) and wide ( HW /HL = 0.94), distinct from neck ( Fig. 9A ). Loreal region slightly inflated; no distinct canthus rostralis. Top of snout and area behind nares shallowly concave. Snout tapered and rounded at tip, relatively short (SN/HL = 0.44), almost twice eye diameter (SN/ EY = 1.9). Eye of modest size ( EY /HL = 0.23, EY / EN = 0.64); pupil vertical, constricted into four lobes; a few anterior supraciliaries slightly larger than adjacent granules, remainder subequal to adjacent granules. Ear opening of moderate size (Ear/HL = 0.075), vertically elliptical; distance between ear and eye almost half again as large as eye diameter ( EE / EY = 1.4). Rostral approximately half again as wide (2.9 mm) as high (1.9 mm); length 1.1 mm; highest just medial to nares, lower medially, with medial suture on dorsal half. Supranasals separated by single large internasal along posterior rostral margin. Rostral in contact with first supralabials, two supranasals, and one internasal. External nares circular; each bordered by rostral, single supranasal, first supralabial, and three postnasals. Each supranasal bordered posteriorly by three small postsupranasals, all <<50% size of supranasal. Mental triangular, 2.0 mm wide, rear margin slightly scalloped. Mental bordered posteriorly by two elongate postmentals that are longer than mental ( Fig. 9B ), these each bordered posteriorly by three round scales same size as those on chin. Postmentals bordered laterally by shorter squarish subinfralabials, gradually decreasing in size posteriorly. First infralabial bordered below by postmental and barely touching (on left side) subinfralabial, second infralabial bordered by two subinfralabials, and third infralabials by three subinfralabials; subinfralabials behind this increasingly smaller, becoming granular posteriorly. Supralabials to mid-orbital position eight on each side; four tiny supralabials posterior to this; angle of jaw bordered with granular scales. Infralabials ten on each side.

Body of fairly robust habitus (TrL/ SVL = 0.46), slightly depressed. Dorsal scales on head, body, limbs, and throat small juxtaposed granules, slightly smaller on neck, head, and limbs, largest on sides and dorsum; tubercles absent. Ventral scales larger, flat, smooth, subimbricate, larger midventrally, gradually decreasing in size laterally to become granular. Skin folds absent on body and limbs.

Enlarged precloacal/femoral scales in single series of 44 scales, containing 37 pores extending in a curved chevron to center of each thigh ( Fig. 9D ), pores larger medially; thigh scales anterior to this row flat, subimbricate, subequal in size to those immediately posterior to row; enlarged scales anterior to pore-bearing series extending laterally along entire length of pore series. Enlarged, imbricate scales form a pubic patch between precloacal series and vent, decreasing slightly in size posteriorly; seven scales in a row between apex of enlarged precloacal series and vent. Scales under arms flat, small, subimbricate; those under hindlimbs enlarged, flat, imbricate; scales on palms and soles granular to subimbricate.

Fore- and hindlimbs well-developed ( FA / SVL = 0.12, CS / SVL = 0.15). Digits well-developed, with broad pads on toes ( T 4W/ T 4L = 0.44), all but first fingers with well-developed recurved claws; clawed terminal phalanges on all digits except T 1 laterally compressed, free above, arising from toe pad, inset from its margin, extending slightly beyond it; claw on T 1 small, terminal, extending slightly beyond toe-pad margin. Subdigital lamellae narrow and smooth, all undivided, most forming a shallowly curved chevron medially ( Fig. 9C ); lamellae extend for only half length of each toe ( T 4lamellaeL/ T 4L = 0.54). Lamellae of manus 8-10-11-11-11 on right, 8-9-11-11-10 on left; of pes 10-10-12-11-11 on right, 10-11-12-12-11 on left. Relative lengths of digits on manus and pes I <II <III ≈ V <IV. Webbing present between all digits, reduced on hands, most extensive between T 3 and T 4 ( T 3 T 4webL/ T 4L = 0.21, T 4 T 5webL/ T 4L = 0.13).

Original tail 4 mm, regenerated tail 32 mm, wide ( TW / SVL = 0.13) and flattened, no lateral serrations. Tail with small subimbricate scales dorsally; under tail with mix of midventral row of narrow, wide, flat, imbricate scales and smaller interspersed scales, the latter predominating posteriorly ( Fig. 3D ); laterally scales much smaller, flat, subimbricate, decreasing in size laterally and dorsally. Cloacal sacs swollen, with single oblong external orifice situated near each lateral margin of vent; three slightly enlarged, blunt postcloacal spurs on each side of tailbase; midventral scales of sac flat, subimbricate, larger posteriorly, slightly larger than those ventrolaterally.

Color in preservative: Dorsal ground color on body, head, and limbs medium brown, with numerous pale-brown spots of varying sizes and with extensive dark-brown marbling. Top of head similar; dark-brown preocular stripe, bordered above by dirty-white preocular stripe, bordered above by dark brown. Supralabials spotted with pale tan and dark brown. Regenerated tail medium gray brown with scattered dark-brown granules and no pale-brown spots, contrasting with pattern on trunk. Venter white with pale-brown dusting on throat and palmar and plantar surfaces; lamellae gray brown. Iris pale bronze with red-brown veins and dots, densest near pupil.

Measurements (in mm).— SVL = 69.5, TrL = 32.0, FA = 8.5, CS = 10.1, HL = 16.1, HW = 15.2, HH = 8.3, Ear = 1.2, EE = 5.3, EY = 3.7, SN = 7.1, EN = 5.8, IN = 2.6, T 4L = 6.1, T 4W = 2.7, T 4lamellaeL = 3.3, T 3 T 4webL = 1.3, T 4 T 5webL = 0.8, mass in life = 7.25 g.

Variation.—The sexes are the same size, and little mensural variation is evident in the sample ( Table 3), with variation in toe width and webbing being most significant. Meristic variation is nominal. Though digital lamellae are complete, the subterminal lamellae are sometimes deeply notched and may superficially appear to be divided, though the sides of each seem to be connected across their proximal edge. This state is clearest in two of the specimens ( UMMZ 245460–61) from Opea Island but does not appear in specimens from Normanby Island.

Subcaudal shape varies depending on whether the tail is original or regenerated. The tail of the holotype is regenerated and contains many wide and thin subcaudals ( Fig. 3D ), as does that of UMMZ 245462; however, the only paratype with an original tail (BPBM 19771) clearly has small, subequal subcaudals ( Fig. 3C ) that are like those seen in G. oceanica and in contrast to the giant species described above. The regenerated tails of the holotype and two paratypes (UMMZ 245458, 245462) are also much wider than the original tail of BPBM 19771; both observations suggest the possibility of a different growth pattern in the morphology of regenerated tails in this species.

In BPBM 19771, the dorsal color pattern on the tail is similar to the dorsal trunk, being medium-brown with small dark-brown flecks, the ventral color is white with small dark-brown flecks. UMMZ 244057 is similar in color pattern to the holotype but with less dark-brown marbling, and UMMZ 244056 and 245059–60 have even less contrast in dorsal pattern elements. BPBM 19771 has more of a reddish cast than do the other specimens and the darker elements dorsally more concentrated in narrow bands and with scattered dark-brown granules. All eight paratypes have more brown dusting on the belly and under the legs.

Color in life.—Field notes for the holotype read “Dorsum brown with pale tan, black-margined ocelli. Venter lemon yellow. Iris pale tan. Pale-tan spots on head. Margins of ocelli unevenly black.” UMMZ 244056–57 were also noted to have bands of yellow-tan spots margined in dark brown, yellowish brown ground color with some brown spots, and lemon-yellow venter. BPBM 19771 was noted to have a pale-yellow chin and throat and bright-orange subcaudal surface, and UMMZ 245458 had a lemon-yellow venter. The pale spots in UMMZ 244056 are clearly arrayed in bands across the body, as are many of the dark-brown markings ( Fig. 4C ); iris color in this animal was pale bronze in life.

Etymology.—The species name is a feminine compound adjective from the Latin macula, meaning “spot” and cinctum, meaning “belt”, meaning “banded with spots”.

Range.—Known from Normanby Island and from the Suau area of southernmost mainland New Guinea, from roughly sea level to 100 m a.s.l. ( Fig. 5 ).

Ecology.—All animals on Normanby Island came from the area surrounding a dispersed village with low human density; habitat here is a mix of advanced secondary forest and open clearings around the houses. The Suau animal came from primary rainforest; those from Opea Island were from undisturbed coastal forest.

Remarks.—The bold color pattern seen in life ( Fig. 3C ) fades significantly in preservative, but the pale spots remain evident although the dark-brown interstices can become significantly more clouded.

One specimen from Guleguleu , Normanby Island , 9.99° S, 151.29° E ( AMS 129847 ) likely belongs to this species because of its presence on Normanby Island and its previous assignment to G. oceanica ( Sistrom et al. 2009) . I have not seen this specimen to confirm this, but I map its locality on eastern Normanby Island ( Fig. 5 ) .

Figures

FIGURE 3. Ventral views of tails of (A) Gehyra chrysopeleia, BPBM 19772, holotype; (B) G.aquilonia, BPBM 34745, holotype; (C) G. maculicincta, BPBM 19771, paratype, showing small, subequal subcaudals of an original tail; (D) G. maculicincta, UMMZ 244055, holotype, showing wide, thin subcaudals of a regenerated tail; (E) G. louisiadensis, BPBM 19763, holotype. Scale bars = 5 mm.

FIGURE 4. Portraits in life of (A) Gehyra chrysopeleia, BPBM 19772, holotype; (B) G. aquilonia, BPBM 34745, holotype; (C) G. maculicincta, UMMZ 244056, paratype; (D) G. louisiadensis, BPBM 19764, paratype; (E) G. oceanica, American Samoa; (F) G. membranacruralis, UMMZ 247752, Varirata National Park, Central Province, PNG. Photo credits: (A) G. Shea, (E) U.S. Geological Survey, (F) V. Weijola, remainder F. Kraus.

FIGURE 5. Map of the Milne Bay region of Papua New Guinea showing collecting localities for species described herein. Solid circle = type locality for both Gehyra chrysopeleia and G. louisiadensis, open circles = additional localities for G. louisiadensis, solid square = type locality for G. maculicincta, open squares = additional localities for G. maculicincta.

FIGURE 8. Bivariate plot of numbers of precloacal/femoral pores vs. numbers of subdigital lamellae on the fourth toe. Lamellae numbers for each specimen are averages of the numbers from each foot. Stars = Gehyra maculicincta, squares = G. louisiadensis, solid circles = Micronesian lineage of G. oceanica, open circles = Pacific lineage of G. oceanica.

FIGURE 9. Details of holotype of Gehyra maculicincta, UMMZ 244055. (A) head, (B) chin, (C) right foot, and (D) precloacal/ femoral pore series. Scale bars = 5 mm.