Cyrtodactylus mamberamo, Oliver & Boothroyd & Tjaturadi & Riyanto & Iskandar & Richards, 2024

Oliver, Paul M., Boothroyd, Nicholas, Tjaturadi, Burhan, Riyanto, Awal, Iskandar, Djoko T. & Richards, Stephen J., 2024, A new species of narrow-banded Cyrtodactylus (Gekkonidae) from northern New Guinea, Zootaxa 5506 (1), pp. 79-92 : 82-88

Cyrtodactylus mamberamo sp. nov.

Mamberamo Basin Bent-toed Gecko urn:lsid:zoobank.org:act:F9F01B5C-5DA6-4C79-BE0E-7524A15761C3

Figs. 1–3 , 4A–B

Cyrtodactylus sp. ‘Mamberamo’ Tallowin et al. 2018; Grismer et al. 2021a

Holotype.— MZB lace 5312 (field number SJR 9807 ), adult male, foothills of Foja Mountains , Kaliwiri Camp , Kwerba village , Mamberamo Tengah district, Mamberamo Raya regency (2.6411°S, 138.4152°E; 100 m. a.s.l.), Papua Province, Indonesia, collected by Stephen Richards and Burhan Tjaturadi on 17 November 2005.

Paratypes.—(n = 6). MZB lace 5343 (field number SJR9789 ), female, same locality and collector details as holotype, collected on 16 November 2005 ; MZB lace 5439 ( SJR6085 ), adult male, foothills of Foja Mountains (2.3705°S, 138.2126°E; ~ 500 m. a.s.l,), Papua Province, Indonesia, collected by Stephen Richards and Burhan Tjaturadi on 18 July 2004 ; MZB lace 5437 ( SJR6032 ), adult male, Marina Valen Village (2.3902°S, 138.1957°E; 350 m. a.s.l,), Papua Province, Indonesia, collected by Burhan Tjaturadi on 15 July 2004 ; SAMA R62645 ( JCU5669 ), female, Furu Camp approximately 3 km SE Dabra, Mamberamo Basin, Papua Province (3.2844°S, 138.6361°E; 90 m a.s.l.), Papua Province, Indonesia, collected by Stephen Richards, Burhan Tjaturadi and Djoko Iskandar on 2 September 2000 ; SAMA R62646 ( SJR [ JCUNQ5610 ]) adult female, Yongsu , Cyclops Mountains (2.4383°S, 140.5145°E; 0 m a.s.l.), Papua Province, Indonesia, collected by Stephen Richards, Burhan Tjaturadi and Djoko Iskandar on 25 August 2000 ; AMS R130352 ( FE250 ), adult male, Wilbeite Village (3.416°S, 142.116°E; ~ 870 m a.s.l.), West Sepik Province, Papua New Guinea, collected by T. Flannery on 6 November 1988 .

Referred Material.—(n = 18). BNHM 1938.6 .6.70, Sabron, Cyclops Mountains , Papua Province, Indonesia ; CAS 89683 , Lake Sentani , Papua Province, Indonesia ; ZMA. RENA.11873, “ Noordwyk res Hollandia ”, Indonesia; ZMA . RENA.15383–5, “ Prauwenbivak am Idenburg River ”, Papua Province Indonesia; ZMA . RENA.15382, “ Njao , a/d Tjano, N-New Guinea”, Indonesia; ZMA . RENA.17885, “ Pioniersbivak am Idenburg River ”, Indonesia ; MZB lace 3561–3564, Yongsu , Cyclops Mountains (2.4383°S, 140.5145°E; 0 m a.s.l.), Papua Province, Indonesia ; MZB lace 3565–3566, Furu Camp , Papua Province, Indonesia ; MZB lace 2303 (2 specimens), Siewa , Wapoga River Basin (3.0367°S, 136.3752°E; 50 m a.s.l.), Papua Province, Indonesia ; ZMB 62271 , 54 km along the road from Nabire after Mapia (3.4967°S; 135.7315°E, 750 m. a.s.l.), Papua Tengah Province, Indonesia ; ZMB 62272 , Unipo Village , along the road between Nabire and Mapia (3.5305°S, 135.933°E, 250 m a.s.l.), Papua Tengah Province, Indonesia .

Diagnosis.— Cyrtodactylus mamberamo sp. nov. can be distinguished from all other Melanesian Cyrtodactylus by the unique combination of moderately large adult size (SVL up to at least 94 mm), throat tubercles absent, medial row of transversely enlarged subcaudal scales present on original tail, upper arm with enlarged tubercles, dorsal pattern consisting of six or more thin light-buff transverse bands with thin dark-brown anterior borders of equivalent width, regions of dorsum between bands evenly pale to medium brown, original tail with 8–11 thin pale bands typically narrower in width than maximum width of tail, and males with widely disjunct series of small precloacal (11–17) and femoral (7–17) pores on each side (30–38 in total).

Description of holotype.—Adult male of moderate size (SVL 85.0 mm, TrK 37.2 mm) with largely regrown tail (22 mm original, 72 mm regrown). Head large (HL/SVL 0.26), moderately wide (HW/SVL 0.19), clearly distinct from neck in dorsal profile ( Fig. 2 ). Snout shorter than broad, truncate in lateral profile, rounded in dorsal profile. Loreal region slightly inflated, interorbital region and top of snout concave. Canthus rostralis rounded, weakly defined, eye-to-naris distance greater than orbital diameter (EN/OrB 1.23). Eyes large (OrB /HL 0.30), sunken into sockets, pupil vertical; supraciliaries extending from anteroventral to posterodorsal edge of orbit, largest at anterodorsal corner. Ear openings roughly triangular, anterior portion much narrower than posterior portion, bordered by small skin fold at posterodorsal corner.

Rostral scale sub-quadrangular with slight medial notch on dorsal edge, wider (4.4 mm) than high (3.0 mm), bordered dorsally by two square supranasals and two irregular internasals of similar size, with third much smaller rounded internasal sitting above left large internasal. Nares bordered by rostral, first supralabial, four (right) or five (left) granular postnasals, a distinctly enlarged ovoid dorsal postnasal approximately twice diameter of other postnasals, and a supranasal. Supralabials 12 to rictus of jaw, nine on left and ten on right to midpoint of eye, variable in size and proportions, anteriormost taller than wide, becoming wider than high medially, then diminishing in size and becoming taller than wide towards posterior edge of jaw. Head, temporal, and nuchal scales small and granular, nuchal and temporal regions with numerous low rounded tubercules approximately 2–3 times diameter of surrounding scales. Infralabials 11 to rictus of jaw, wider than high, becoming smaller posteriorly, bordered ventrally by several rows of slightly enlarged scales grading into smaller granular gular scales. Mental wider (2.5 mm) than long (1.6 mm), anterior edge rounded, concave at point of contact with two postmentals; postmentals large (length 3 mm), in contact with each other and first infralabial on respective sides.

Body moderately slender (TrK/SVL 0.44), narrower than head in dorsal profile, with distinct ventrolateral folds. Dorsum with approximately 18 transverse rows of low unkeeled tubercles up to three times diameter of surrounding small granular scales. Tubercles along ventrolateral folds distinct, becoming larger posteriorly, 36 on both left and right. Ventral scales much larger than dorsal scales, increasing in size medially, arranged in approximately 42 rows at midpoint of torso. Precloacal pores rounded, indistinct, 12 in total, arranged in continuous very shallow chevron. Femoral pores very small, indistinct, nine on both sides, arranged in straight unbroken series extending from knee for approximately one third length of femur. Enlarged femoral scales arranged in continuous series from knee to precloacal region, pore-bearing series bordered anteriorly by series of similar-sized scales and posteriorly by series of distinctly smaller scales.

Limbs slender, forelimbs shorter (FA/SVL 0.14, HDL/SVL 0.17) and less robust than hindlimbs. Dorsal and lateral surfaces of upper and lower limbs covered with numerous rounded tubercules up to two times diameter of surrounding granular scales; on hindlimbs some tubercules extend to dorsal surfaces of pes. Digits long, well developed, with distinct inflection at basal interphalangeal joints; subdigital lamellae smooth, rounded, undivided, and laterally expanded proximal to digital inflection (8-10-10-10-8 on manus; 10-11-12-10-9 on pes); lamellae distal to digital inflection narrow (4-5-6-5-4 on manus; 5-5-7-6-4 on pes); between 3–7 rows of rounded scales between narrow and widened lamellar series; large, recurved claws sheathed by one dorsal and one ventral scale; claw missing from second digit of right pes.

Tail thin, moderately long (94 mm total length, 72 mm regrown). Original portion of tail with two dorsal ridges and two lateral ridges running along length; scalation irregular, small granular dorsal scales grade into much larger ventral scales, medial row of transversely enlarged scales starts to form approximately 21 mm posterior to vent, just before break between original and regrown tail; numerous enlarged tubercules on dorsal and lateral surfaces, tending to coalesce into distinct whorls with increasing distance from base of tail. Regrown tail without tubercles and with highly irregular scalation. Three low, rounded, postcloacal tubercles on each side of tail.

Colouration in preservative.—Base colouration of dorsal and lateral surfaces of head, neck, torso, and limbs medium brown. Body and neck with series of eight thin, irregular creamish transverse bands (including two nuchal bands) with thin dark-brown indistinctly edged anterior borders of equivalent width; second band chevron shaped, extending anteriorly almost to posterior edge of ear; two posterior-most bands offset at their midpoint. Dorsal tubercles distinctly lighter than ground colouration on most of dorsum, especially towards sides of body, unless positioned within either creamish or dark-brown areas of transverse bands wherein they tend to match surrounding colour. Under a microscope base colouration of dorsum medium-brown with extensive dark-brown maculations; varying density of these maculations is responsible for outward appearance of darker and lighter areas. Venter light buff with few scattered dark-brown maculations. Limb colouration similar to torso, brown on dorsal surfaces, light buff on ventral surfaces, with no obvious pattern other than numerous distinctly lighter tubercles. Original portion of tail with similar dorsal colouration and pattern to torso, with three thin light bands, posteriormost band wider and with dark-brown splotch on posterior as well as anterior margin, ventral surfaces of tail light buff with scattered brown maculations. Regrown portion of tail on both dorsal and ventral surfaces light brown with dense tiny brown maculations that do not form any obvious pattern.

Summary measurements of holotype (in mm).—SVL 85.0; TL 94.0; OT 22.0; TrK 37.2; HW 15.9; HL 22.3; HH 9.4; OrB 6.6; FA 12.1; HDL 15.0.

Variation.—Mensural data summarised (in mm) for all adults in the type series (four males and three females) are as follows (mean, with the range in parentheses): SVL 82.3 (70.0–92.0); TrK 36.3 (30.5–41.4); OT (n=2) (103– 119); HW 16.0 (13.5–17.7); HL 22.2 (19.7–24.8); HH 9.5 (8.1–10.5); OrB 6.6 (6.0–7.3); FA 12.4 (10.5–14.3); HDL 15.1 (12.9–16.7). Summary meristic data for these same individuals are: SUPR (to midpoint of eye) 9.3 (9–10); SUPR (rictus of mouth) 12.0 (11–13); INFR 11.9 (11–13); Toe I LAM (manus) 8.0 (7–10) expanded, 3.4 (3–4) narrow; Toe 1 LAM (pes) 8.3 (7–9) expanded, 3.4 (3–4) narrow; Toe IV LAM (manus) 11.0 (10–13) expanded, 5.9 (5–7) narrow; Toe IV LAM (pes) 13.6 (12–15) expanded, 5.6 (5–6) narrow; DTR 20.4 (19–23); LFT 33.7 (25–39); VENT 48.6 (47–52); PP (n=4) 14.3 (12–16); FP (n=4) 13.7(9–14); PCTUB 3–4 on each side.

While all specimens have at least some tubercles on the upper arm, there is considerable variation in how prominent and numerous these are. Some large animals have few enlarged tubercles (e.g., MZB lace 5439, SAMA R62646), often concentrated close to the shoulder and with colouration matching surrounding areas. On smaller animals the tubercles are more abundant, more evenly spread across the upper forelimb, and relatively more prominent in size, shape and colouration when compared against surrounding scales. This variation does not appear to be geographically based and we suspect that it is ontogenetic, with larger animals tending to have less prominent arm tubercles. However, examination of further specimens of varying size is required to confirm this.

In preservative, colouration and pattern of paratypes broadly matches the holotype ( Fig. 3 ). Base colouration is marginally darker brown in some specimens, especially the easternmost specimen (AMS R130352). The creamish transverse bands between head and cloaca (including nuchal bands) vary in number (6–9), and most specimens (five out of seven) tend to have at least some bands that are offset at midpoint of dorsum, or are half bands, especially towards the posterior of the torso. In two large animals (SAMA R62646 and AMS R130352) the anteriormost light bands also have dark-brown posterior margins. The colouration of the dorsal and limb tubercles also varies; in some animals they are distinctly lighter than surrounding regions, while in other specimens the tubercles are less contrasting in colouration. The venter shows varying density of brown maculations, such that overall appearance without a microscope varies from creamish to light buff. Original tails with base dorsal and lateral colouration typically grading from medium brown at the base of tail to dark brown less than a third distance along its length and then back to light brown along approximately final quarter of tail, with 9–11 thin, ragged, off-white bands that typically have a width less than half the maximum width of the tail; in areas of the tail with a light-brown background colouration the anterior edge of light tail bands has a dark-brown border as per the dorsum.

Data for and photographs of referred material that we have not directly examined (see Günther & Rösler 2003) show animals that are consistently similar to the type series, but they slightly extend the maximum known size (with the largest specimen (ZMB 62271) having a SVL of 94 mm), and the range of variation for numbers of expressed precloacal (11–17) and femoral (7–17) pores in males.

Colouration in life.—Overall, the colour and pattern of animals photographed in life resembles that of the preserved specimens. Photographed animals show variation in the intensity of the brown background colouration on the dorsum and limbs ( Figs 1 , 4A–B ). Some of this variation may be temporal (i.e., night versus day), but we lack time series to confirm this. Lateral regions of the body are particularly pale in some photographed specimens (not collected) and sometimes have a series of light creamish blotches. The supraciliaries, and sometimes labials and postcloacal tubercles, tend to be yellow, and there is often additional indistinct yellow blotching along the lateral regions of the torso. Dorsal and lateral tubercles contrast against surrounding scales more prominently in life than in preservative and sometimes form a pattern of thin transverse lines on the hindlimbs (including on the holotype). Bands on the original tail range from creamish to white, regrown tail sections are unpatterned with a distinct yellowish wash. The iris is greenish-grey with extensive dark-brown reticulations and a yellowish margin along the border of the pupil. The tongue is pink.

Comparisons.— Cyrtodactylus mamberamo sp. nov. can be distinguished from all but two other Melanesian and Wallacean Cyrtodactylus by the combination of moderately large size (adult SVL over 80 mm), throat lacking enlarged tubercles, dorsal pattern consisting of numerous (usually more than six, or eight if nuchal bands are also counted) thin transverse light-buff bands with dark-brown borders on a lighter brown background, subcaudal scales in medial series distinctly widened, and males with small precloacal and femoral pores in widely disjunct series.

Cyrtodactylus mamberamo sp. nov. differs from the remaining two species as follows: from C. aaroni Günther and Rösler (2003) in usually having at least some tubercles on the upper arm (versus absent); narrow, clearly defined light buff bands on the dorsum of same width as their dark-brown anterior margins (versus wider than the dark-brown anterior border, and fading at their posterior edge); and a higher number of precloacal pores in males (11–17 versus 5–8); and from C. mimikanus ( Fig. 4C–D ) by its slightly smaller size (max SVL 94 mm versus 103 mm), dorsal pattern consisting of thin light-buff bands with brown anterior borders of similar width (versus light buff bands with much wider dark-brown anterior borders), narrower light tail bands (widest bands typically less than half maximum width of tail width versus typically approaching maximum width of tail), and higher number of precloacal pores in males (11–17 versus 7–9).

Etymology.—Named after the Mamberamo River Basin where the range of this species is centred. Used as a noun in apposition.

Distribution.—Known from a large area of lowland and hill forest in north-western mainland New Guinea, extending from Nabire in Indonesia in the west, through the Mamberamo Basin to the Cyclops Mountains in the north to at least Wilbeite Village in the Bewani Mountains in north-western Papua New Guinea in the east ( Fig. 5 ).

Natural History.— Cyrtodactylus mamberamo sp. nov. has been recorded from lowland and hill forest habitats from sea level up to at least 870 m a.s.l. Most locations are in slightly elevated foothill forest habitats ( Fig. 6A ), and it is unknown whether the new species occurs in the swampy lowlands of the Mamberamo Basin. It has been recorded from both primary forest and from moderately disturbed forest around villages. It is typically found within three metres of the forest floor climbing on small trees, saplings, or vines. Many, but not all, records are from vegetation along or overhanging streams (S. Richards, pers. obs; Chien Lee, pers. com.; Fig. 6B ), suggesting this is their preferred habitat. However, this may also reflect a bias for researchers to search along relatively open creeklines or for such areas to be open enough to permit easy viewing of the lizards.

In many areas where it was seen and collected, C. mamberamo sp. nov. was the only Cyrtodactylus species encountered. However, it occurs in sympatry with C. papuensis (Brongersma, 1934) at Siewa in the Wapoga River drainage, in near sympatry with C. equestris Oliver, Richards, Mumpuni & Rösler, 2016 in the foothills of the Foja Mountains (S. Richards, pers. obs.), and with C. rex Oliver, Richards, Mumpuni & Rösler, 2016 and the ecologically similar C. sermowaiensis (De Rooji, 1915) around Wilbeite Village in West Sepik Province.At this last site, material was brought in by local collectors, and it is unknown whether this species and the similar-sized C. sermowaiensis occur in sympatry, or whether there is some niche displacement. Based on the numbers of specimens obtained by local collectors at Wilbeite C. sermowaiensis was more common than C. mamberamo sp. nov. (n = 7 versus n = 1). Alternatively, the two species may occupy different habitats that were targeted differently by local collectors.

Suggested IUCN Conservation status.— Cyrtodactylus mamberamo sp. nov. is widespread ( Fig. 5 ), common where it has been collected, and occurs in areas where large areas of forest remain intact. It has also been recorded in forest that has been moderately disturbed close to human settlements around the city of Jayapura and appears to be able to persist in the face of at least some habitat modification. We therefore suggest the species should be considered Least Concern.

Figures

FIGURE 1. Images in life of uncollected specimens of Cyrtodactylus mamberamo sp. nov. from Papua Province, Indonesia:A) Dabra Village (3.2844°S, 138.6361°E) and B) Nimbokrang (2.58871°S, 140.064112°E). Photos courtesy Chien Lee.

FIGURE 2. Holotype of Cyrtodactylus mamberamo sp. nov. (MZB lace 5312) in preservative: (A) dorsal and (B) ventral view. Scale bar = 10 mm. Photograph by Peter Waddington.

FIGURE 3. Type material of Cyrtodactylus mamberamo sp. nov. showing variation in colour pattern, from left to right: MZB lace 5312 (holotype), MZB lace 5439, SAMA R62646, MZB lace 5343, SAMA R62645, MZB lace 5437. Scale bar = 10mm.

FIGURE 4. Images-in-life of Cyrtodactylus mamberamo sp. nov. (A–B) and C. mimikanus (C–D), all specimens were photographed in Indonesia:A) MZB lace 5343 (SJR9807) (paratype) Kwerba Village; B) MZB lace 5437 Marina Valen Village; and C) and D) Cyrtodactylus mimikanus from Kuala Kencana (4.3990°S, 136.9390°E), Timika area.All photographs by Stephen Richards.

FIGURE 5. Distribution of Cyrtodactylus mamberamo sp. nov. north of the Central Cordillera of New Guinea (blue circles) and C. mimikanus to the south (red circles) based on both museum and photographic records. Green squares indicate additional records from the Vogelkop Peninsula that remain of uncertain taxonomic placement, but which show morphological affinity to C. mimikanus.

FIGURE 6. Details of habitat of Cyrtodactylus mamberamo sp. nov. near Kwerba Village, Indonesia: A) Aerial view of typical foothill forest habitat; and B) interior view of typical habitat along a forest stream.Cyrtodactylus mamberamo sp. nov. is typically collected in vegetation less than three metres above the ground and alongside streams. Photographs by Stephen Richards.