Cyrtodactylus rex, Oliver, Paul M., Richards, Stephen J., Mumpuni, & Roesler, Herbert, 2016

Oliver, Paul M., Richards, Stephen J., Mumpuni, & Roesler, Herbert, 2016, The Knight and the King: two new species of giant bent-toed gecko (Cyrtodactylus, Gekkonidae, Squamata) from northern New Guinea, with comments on endemism in the North Papuan Mountains, ZooKeys 562, pp. 105-130 : 112-117

Taxon classification Animalia Squamata Gekkonidae

Cyrtodactylus rex sp. n. Figures 2, 5

Holotype.

SAMA R67636 (Field number SJR13190), Papua New Guinea, East Sepik Province, un-named camp in Sepik River basin, (4°24'14"S, 142°17'33"E, 55 m a.s.l.), adult female, collected by S. Richards, 1 March 2011, tissue stored in ethanol at the South Australian Museum ABTC114693.

Paratypes

(n =19). Papua New Guinea: SAMA R67637 (SJR13011) Sandaun Province, Sepik River Basin, un-named camp (4°43'39"S, 141°47'08"E, 425 m a.s.l.), collected by S. Richards on 20 February 2010; BPBM 11522 Morobe Province, Oomsis Forestry Camp (6°41'54.1278"S, 146°48'56.412"E, 400 m a.s.l), collected by A. Allison 3 March 1988; BPBM 18655 Morobe Province, 8.4 km W of Mt Shungol summit (6°47'40.56"S, 146°40'49.98"E, 420 m a.s.l.), collected by F. Kraus 23 October 2003; BPBM 34719 Madang Province, Samorek village (4°42'38.0412"S, 145°24'51.3714"E, 690 m a.s.l.), collected by F. Kraus 1 October 2009; BPBM 34747 East Sepik Province, Joromba River, 16.25 km W of Wewak (3°34.732'S, 143°30.020'E, 227 m a.s.l.), collected by F. Kraus 25 September 2009; AMS R13025 Morobe Province, Lae (6°44'S, 147°00'E), collected by E.L. Troughton 18 May 1945; AMS R31940 Morobe Province, Lae Botanic Gardens (6°44'S, 147°00'E), collected by E.L. Troughton 5 September 1969; AMS R129290 East Sepik Province, Maprik (3°25'S, 143°02'E), collected by W.H. Ewers 5 November 1964; AMS R119548-50 Sandaun Province, Torricelli Mts,Wigote (3°39'S, 142°09'E), collected by T. Flannery 22 July 1985; AMNH 92341-2 Morobe Province, Oomsis Creek (6°41'S, 146°48'E), collected by H.M. Van Deusen April 1959; AMNH 95165-8 Morobe Province, Lae (6°44'S, 147°00'E); AMNH 95169 Morobe Province, Busu River, 8 mi. N of Lae; AMNH 95170 Morobe Province, 13 mi. N of Lae, previous six specimens collected by R. Zweifel & G. Sluder July–August 1964.

Referred material

(n = 7). Papua New Guinea. AMNH 95171 East Sepik Province, Maprik (3°38'S, 143°03'E); AMNH 100048-9 Sandaun Province, Lumi (3°28'S, 142°02'E); AMNH 104871 Madang Province, Alexishafen (5°05'S, 145°48'E); AMNH 103194 Madang Province, Kaibugu (4°54'S, 144°57'E); MCZ 142462 Madang Province, 4 mi. S Madang; MCZ 96201 Morobe Province, Morobe town (7°45'S, 147°36'E).

Diagnosis.

A very large Cyrtodactylus (SVL to 172 mm), with a very broad head (HW/SVL 0.20-0.24), enlarged tubercles across the infra-angular region and often extending across the throat, mid-dorsal tubercles in 21 to 27 rows at midpoint of body, subcaudal scales not transversely widened, high number of mid-body ventral scales in transverse series (49-60), moderate number of femoral and precloacal pores (20-38) in a nearly continuous chevron, narrow dark brown barring on the throat, labials and often venter, and dorsal colour pattern on torso including indistinctly defined alternating dark-brown, medium-brown and whitish regions.

Description of holotype.

A very large (169 mm SVL) and robust gecko. Head very large (HL/SVL 0.27), very wide (HW/SVL 0.23) and clearly distinct from neck. Snout longer than eye diameter, eye to naris distance longer the eye (EN/EYE 1.4), curved in dorsal profile, broadly truncate in lateral profile, mid-loreal region slightly inflated, interorbital region and top of snout slightly concave, canthus rostralis weakly defined. Oval patch of skin missing from top of snout. Eyes large (EYE/HL 0.24), pupil vertical, supraciliaries extending from anteroventral to posterodorsal edge of orbit, longest at the anterodorsal edge. Ear opening roughly circular, bordered by distinct dorsal skin fold.

Rostral broadly rectangular, approximately 1.5 times wider than high with medial suture extending approximately 60% from dorsal edge towards ventral edge, bordered dorsally by two nasals and three smaller internasals. Nares bordered by first supralabial (point contact), rostral, nasal, and series of five to eight granular postnasals. Supralabials generally slightly wider than high, 13 right, 14 left, 10 to midpoint of eye. Head, temporal and nuchal scales small and granular with conical tubercles approximately 2-3 times width of surrounding scales densely distributed across the temporal and nuchal regions. Enlarged infralabials to rictus 14 right, 13 left, anterior infralabials higher than wide, posterior infralabials wider than high, infralabials bordered by rows of enlarged scales that grade into small granular gular scales. Mental triangular, approximately as wide as long, bordered by first infralabials and two pentagonal postmentals. Numerous wide flat tubercles present across posterior region of throat.

Body robust (TrK/SVL 0.43) with distinct ventrolateral folds. Skin heavily tuberculate dorsally and laterally, 33-34 prominent enlarged tubercles along lateral folds, dorsum with up to 23 rows (not including lateral fold) of enlarged conical tubercles up to four times width of surrounding small and granular scales. Ventral scales larger than dorsal scales, increasing in size medially, arranged in approximately 54 rows at midpoint of body, one or two poorly defined rows of enlarged ventral tubercles present just inferior to the lateral fold. Enlarged precloacal and femoral scales in three rows, posterior row longest (47 scales) and extending laterally approximately two thirds length of femur, medial scales distinctly larger.

Limbs robust, forelimbs shorter (FA/SVL 0.15) and less robust than hindlimbs (CS/SVL 0.17). Lateral and dorsal surfaces of hindlimbs with numerous enlarged conical tubercles. Digits long and well developed, inflected at basal interphalangeal joints; subdigital lamellae smooth, rounded and expanded proximal to joint inflection (11 –12–13–15– 11 manus; 10 –14–14–15– 9 pes); narrow distal to digital inflection (7 –9–10–10– 11 manus; 8 –8–12–11– 11 pes) (not including ventral claw sheath); large recurved claws sheathed by a dorsal and ventral scale.

Tail original, partially fractured approximately halfway from base, long and moderately robust, numerous low conical tubercles on dorsal and lateral surfaces close to base, but not extending beyond anterior third of tail, subcaudal scales enlarged, not wider than long, arranged in series 2-4 scales wide, 4 rounded cloacal spurs.

Measurements of holotype

(in mm).SVL 169, TL 177, OT 177, TrK 72.7, HW 38.1, HD HH 24.3, HL 45.1, EN 14.7, IN 6.4, EYE 10.6, EAR 3.2, FA 26.1, CS 29.3.

Color in ethanol.

Dorsum consists of alternating regions of dark greyish-brown, medium grey, and light-grey to dirty off-white. Four dark-brown regions most clearly defined, and consisting of three paired sets of oval, pentagonal and triangular blotches between fore- and hindlimbs, and an additional distinct dark-brown triangular nuchal patch anterior to insertion of forelimbs, and extending anterio-laterally as a stripe through eye and along dorsal edge of supralabials. Ventro-lateral regions of head with wide off-white stripe extending to lower edge of supralabials. Supraciliaries and dorsal tip of snout dark brown. Limbs and toes dirty grey with broad indistinct dark-brown bands on upper and lateral surfaces. Ventral ground colouration off-white with brownish tinge and extensive dark-brown flecks, often covering just a single scale, but also coalescing to form four distinct sets of jagged transverse bars on throat, and less prominent bars and ocelli on torso. Dorsal and lateral surfaces of tail dirty grey with four indistinctly edged dark-brown blotches or bands, and extensive smaller dark brown maculations, stripes or blotches. Subcaudal surfaces dark-brown with scattered lighter grey spots.

Variation.

The type series of 20 specimens includes five adult males with expressed pores (SVL 152-165 mm), 10 females (128-172 mm), and five juveniles or subadults (72-127 mm). Mensural data for the type series are summarized in Table 3. Supralabials counted to center of eye vary from 8-12, to angle of jaw 10-15, infralabials vary from 11-14, fourth toe wide lamellae 10-19, fourth toe narrow lamellae 8-16, mid-belly scale rows 39-60, number of rows of dorsal tubercles 20-27, cloacal spurs 2-6, and expressed femoral and precloacal pores in continuous or near continuous series of 28-38 (males only).

Dorsal pattern always consists of indistinctly defined alternating regions of dark grey brown, medium brown and dirty off-white. Dark grey-brown markings usually most clearly defined, but showing extensive variation in shape and size - usually less than half width of torso, but occasionally wider and varying in shape from small diamonds, transverse bands to paired blotches or triangles. Dark brown ventral barring always present, but on some specimens restricted to throat only, while in others forming a network across throat and venter. All specimens with at least some indistinct dark brown barring on toes and four or five dark brown longitudinal blotches or bands on original tails. Iris in life brick red with extensive fine brown vermiculations (Figure 5).

All specimens heavily tuberculate with usually several indistinct rows of large tubercles extending as much as 10 mm inferior to lateral fold at midpoint of torso. Throat tuberculation varies in extent from a broad band spanning the posterior throat to concentrated in infra-angular regions and largely absent from the throat.

Comparisons.

Cyrtodactylus rex sp. n. is readily distinguished from most other Cyrtodactylus by its very large size (SVL up to 172 mm vs generally <130mm). It further differs from the relatively small number of other large Papuan species as follows. Cyrtodactylus rex sp. n. differs from Cyrtodactylus loriae and Cyrtodactylus serratus in having enlarged tubercles on the infra-angular region and often extending onto and across the throat (vs absent from both regions), a lower number of pores (up to 38 vs. up to 81), and in lacking enlarged tubercles extending the length of the tail (vs. Cyrtodactylus serratus only). Cyrtodactylus rex sp. n. differs from members of the Cyrtodactylus lousiadensis group ( Cyrtodactylus epiroticus (with which it is sympatric in Morobe Province), Cyrtodactylus klugei , Cyrtodactylus lousiadensis , Cyrtodactylus murua , Cyrtodactylus robustus , Cyrtodactylus salomonensis and Cyrtodactylus tripartitus ) by its much smaller subcaudal scales, the presences of extensive tubercles on infra-angular region and often the throat, and in its much more poorly defined dark bands or paired blotches on the dorsum (vs. distinctly edged, unbroken transverse light and dark-brown bands). Cyrtodactylus rex sp. n. differs from Cyrtodactylus zugi by the presence of dark-brown barring on the throat and venter, tuberculation often extending across the throat (vs. on infra-angular region only), and dorsal colour pattern on torso consisting of alternating indistinct dark-brown, medium brown and whitish regions (vs. alternating dark-brown and off-white). Cyrtodactylus rex sp. n. differs from Cyrtodactylus irianjayaensis by the presence of dark-brown barring on the throat and venter (vs. plain and unpatterned), tubercles often extending across the throat (vs. infra-angular region only), dorsal colour pattern on torso consisting of alternating indistinct dark-brown, medium brown and whitish regions (vs. very wide brown transverse blotches on a lighter greyish brown ground colour), and higher number of femoral and precloacal pores (21-38 vs. 7-16). Cyrtodactylus rex sp. n. differs from all populations referred to Cyrtodactylus novaeguineae in its wider head (HW/SVL 0.21-0.24 vs. 0.18-0.19) and larger size (SVL 172 vs. 129 mm), and differs from Cyrtodactylus equestris sp. n. in its larger size (SVL 172 vs. 139 mm), in having a continuous (or nearly so) row of femoral and precloacal pores, presence of dark barring on the throat and ventral surfaces of body (vs. absent), and ‘messier’ dorsal colouration of alternating indistinct dark-brown, medium brown and whitish regions (vs. light-brown transverse bands or blotches on relatively plain light brownish-grey background).

Distribution and natural history.

Widespread in northern Papua New Guinea, extending from Sandaun Province in the west to Morobe Province in the east (Figure 7). Photographs of a specimen from the vicinity of Senggi Village to the south of Jayapura in West Papua Province (kindly provided by Burhan Tjaturadi), indicate that this species also occurs in adjacent parts of Indonesian New Guinea.

The holotype was collected on a low ridge in Sago-dominated swamp forest. Other specimens were collected in lowland and foothill forest at altitudes ranging from near sea level up to 690 m a.s.l.

Etymology.

From the latin for king as it is the largest of the over 200 species of Cyrtodactylus , and amongst the largest of all known geckos ( Bauer 2013).