Cyrtodactylus murua, Kraus, Fred & Allison, Allen, 2006

Kraus, Fred & Allison, Allen, 2006, A new species of Cyrtodactylus (Lacertilia: Gekkonidae) from Papua New Guinea, Zootaxa 1247, pp. 59-68 : 61-66

Cyrtodactylus murua sp. nov.

Fig. 1 a

Holotype

BPBM 17858 (field tag AA 16499), immature female, collected by A. Allison in the vicinity of Guasopa, 9.2182971ºS, 152.943987ºE, 5 m, Woodlark Island, Milne Bay Province, Papua New Guinea, 24 January 2003.

Paratype

AMS R124889, maturing female, collected by G. Mengden at Kulumadau, Woodlark Island, Milne Bay Province, Papua New Guinea, 10 August 1987.

Diagnosis

A large (106–113 mm) species of Cyrtodactylus having a single row of enlarged subcaudal scales; approximately 20–22 irregular rows of prominent, conical dorsal tubercles; uniformly sized scales on throat; poorly developed lateral fold; a dark chevron on the nape followed by three dark brown bands on body, each band narrow laterally, widening mid­dorsally, with dark brown, irregular margins, and approximately twice width of intervening ground color; pale lips; and head, limbs, and interspaces between dorsal bands mottled with dark brown.

Comparisons with other species

Cyrtodactylus murua can be easily distinguished from all other Papuan members of the genus except C. louisiadensis and C. aaroni in having a single row of enlarged subcaudal scales. From C. aaroni it is distinguished by its larger size (106–113 mm vs. 70–86.5 mm in C. aaroni ) and in having fewer dark dorsal bands between the nape and hindlimbs (3 vs. 6 or more in C. aaroni ). From C. louisiadensis it is distinguished by having the dark dorsal bands at least twice as wide as the intervening ground color (vs. narrower or equal in width in C. louisiadensis ), broadening mid­dorsally (vs. of even width across the dorsum in C. louisiadensis ), and with irregular margins (vs. straight margins in C. louisiadensis , Fig. 1 ). Furthermore, the lips of C. murua are light (vs. dark in C. louisiadensis ); the head, limbs, and dorsal ground color are mottled with dark brown (vs. uniform brown in C. louisiadensis ), and there are fewer rows of dorsal tubercles (approximately 20–22 vs. 24 or more in C. louisiadensis ).

Description of holotype

An immature female nearing adulthood, with small ovarian follicles, mid­ventral incision, and tail separated from body. Animal medium­sized (SV = 106 mm, TrL = 48 mm); tail crooked and unamenable to accurate measurement, approximately as long as SV. Head relatively long (HL/SV = 0.34) and wide (HW/HL = 0.69), not depressed (HH/HL = 0.38), distinct from neck. Loreal region slightly inflated; canthus rostralis absent. Interorbital region and top of snout concave. Snout relatively long (SN/HL = 0.41), much longer than eye diameter (SN/EY = 1.9). Eye relatively large (EY/HL = 0.22); pupil vertical, with crenellated margins; supraciliaries large, frill­like, well­differentiated from adjacent granules. Ear opening small (Ear/HL = 0.067), round, with ventrolateral 40% shallowly indented; distance between ear and eye larger than eye diameter. Rostral more than half (1.8 mm) as high as wide (3.1 mm), highest just medial to nares and shallowly depressed between these points; length (1.2 mm) two­thirds height; partially divided dorsally by weak rostral groove that bifurcates anteriorly. Two enlarged supranasals separated by two smaller internasals. Rostral in contact with first supralabials, two supranasals, and one internasal. External nares circular; each bordered by rostral, supranasal, first supralabial, one nasal, and one dorsal granular scale. First supralabial has a short extension that reaches dorsally to posterioventral margin of naris. Nasal bordered posteriorly by four small granular scales. Four rows of small scales separate orbit from supralabials at narrowest point. Mental shallowly triangular, wider (6.1 mm) than long (3.7 mm). Mental bordered posteriorly by two enlarged postmentals. First 5–6 infralabials bordered by enlarged, elongate scales, these followed posteriorly by tiny granules. Supralabials to mid­orbital position nine on right side, 11 on left; to angle of jaw ten on right, 12 on left. Infralabials ten on right, nine on left. Scale rows between center of orbits ~65.

Body moderately robust (TrL/SV = 0.45), with poorly developed ventrolateral folds consisting of slightly enlarged granules. Dorsal scales on head, body, and limbs tiny, juxtaposed granules; these more conical anteriorly and flatter posteriorly; each granule with small raised asperities. Enlarged conical tubercles present on head, body, and limbs; best developed posteriorly; most with one primary, anterior keel and numerous short, shallow ridges around remainder of tubercle. Ventral scales flat and smooth, those on chin and throat smaller than on abdomen. Tubercles arranged irregularly in approximately 20–22 poorly defined rows between the lateral folds.

Precloacal and femoral pores absent. Scales of precloacal and femoral regions of approximately uniform size and not distinct from those on abdomen. No precloacal groove. Scales on palms and soles rounded, smooth.

Fore­ and hindlimbs relatively well­developed (FA/SV = 0.12, CS/SV = 0.16). Digits well­developed, reflected at basal interphalangeal joints; all with robust, slightly recurved claws surrounded by two scales. Subdigital lamellae narrow and smooth, expanded proximally. Lamellae of manus 16­19­21­20­18 on right, 16­19­21­21­19 on left; of pes 17­21­22­25­21 on right, 15­20­23­24­21 on left. Relative lengths of digits on manus and pes I <V <II <III <IV. No interdigital webbing on manus, slight webbing on pes.

Tail with regenerated distal half, rather narrow base (TW/SV = 0.084), tapering to a blunt point, with single row of enlarged subcaudals throughout original portion. Cloacal sacs small, with small external orifices situated near lateral margins of vent. Scales of tail small, flat, smooth, subimbricate; with five rows of enlarged tubercles dorsally, decreasing in prominence posteriorly; one or two small, flat postcloacal spurs on each side of tailbase.

Color in preservative: Dorsal ground color light brown with a pale salmon cast, with one chocolate­brown chevron on nape whose lateral arms extend forward to behind each eye, these followed by three wide bands of same color on body and three more on anterior half of tail. Dorsal bands with irregular margins, narrowed laterally and expanded middorsally, and with margins outlined in darker brown. Last band on body narrowly partitioned vertebrally by ground color and anterior two partially partitioned ( Fig. 1 a). Top of head, limbs, and interspaces between bands with obscure darker brown mottling. Tubercles generally lighter than dorsal colors and, hence, appearing conspicuous. Labials white with some brown dusting, especially anteriorly. Narrow white border between ear and eye along lower margin of each lateral arm of the anterior dark chevron. Ventral scales light with medium­brown stippling, imparting to the ventrum an overall dirty appearance.

Measurements (in mm). – SV = 106, TrL = 48, TW = 8.9, FA = 13.2, CS = 17.5, HL = 35.6, HW = 24.7, HH = 13.5, Ear = 2.4, EE = 10.7, EY = 7.7, SN = 14.5, EN = 11.4, IN = 4.5, IO = 9.6.

Va r i a t i o n

The single paratype is very similar to the holotype in most details but lacks all but the first 2cm of tail; has larger, yolking follicles; 10 supralabials to center of eye; 10 infralabials on right side, and 11 on left; and has the last dorsal band broken into two lateral blotches on each side and an elongate mid­dorsal blotch narrowly separated from each lateral blotch by a finger of ground color. Measurements for the paratype are SV = 113, TrL = 50, TW = 8.0, FA = –, CS = 20.8, HL = 34.0, HW = 22.9, HH = 16.4, Ear = 2.8, EE = 9.2, EY = 8.2, SN = 14.8, EN = 11.7, IN = 4.4, IO = 10.4.

Etymology

The trivial epithet is the local name for Woodlark Island and is a noun in apposition.

Range

Known only from Woodlark Island, Milne Bay Province, Papua New Guinea ( Fig. 2 ).

Ecology

We collected the holotype at night in a large, strangling fig ( Ficus sp.) in a patch of disturbed lowland forest about 500 m from the coast, along a disused road constructed during WWII ( Fig. 3 ). The forest, which was growing on limestone substrate, had large open patches in various stages of regeneration from swidden agriculture. Tree ferns ( Asplenium spp.) and other epiphytes were common in the tree crowns and many of the tree trunks were covered with vines (particularly Monstera sp.). The fig on which the lizard was collected was the largest tree in the area, with a dbh of about 1 m and a height of 25– 30 m.

We first observed the lizard in the early evening, around 1900 h, on the trunk of the tree about 4 m above the ground. When illuminated with our head lamps it began actively moving up and down the trunk about 4–6 m above the ground while waving its tail back and forth. We pursued it for about five minutes until it disappeared into a crevice. It was again emergent when we returned to the tree 30 minutes later and we were able to climb into the tree and capture it. We actively looked for more on this and subsequent nights but saw none. McCoy (2000) reported that the related Cyrtodactylus louisiadensis is often observed in strangling figs in the Solomon Islands.

Other lizards common in the area included five species of skinks, Carlia eothen Zug , Emoia caeruleocauda (de Vis), E. jakati (Kopstein) , Prasinohaema virens (Peters) , Lamprolepis smaragdina (Lesson) , and a gecko, Gekko vittatus (Houttuyn) . Several species of ground­dwelling snakes, including Candoia paulsoni (Stull) , Stegonotus cucullatus (Duméril, Bibron & Duméril) , and Aspidomorphus lineaticollis (Werner) , were also relatively common in the surrounding area, as was the arboreal Boiga irregularis (Merrem) .

Figures

FIGURE 1. Photograph of (A) holotype of Cyrtodactylus murua, BPBM 17858, from Woodlark Island, and (B) C. louisiadensis from Sudest Island, in life. Photos by A. Allison and G. Shea, respectively.

FIGURE 2. Map of the offshore islands of Milne Bay Province, Papua New Guinea, showing localities of holotype (closed circle) and paratype (open circle) of Cyrtodactylus murua on Woodlark Island.

FIGURE 3. Photograph of the type locality. The holotype was collected ca. 4 m above the ground from the trunk of the strangling fig in the center of the photo, just to the right of the road. Note the Monstera sp. vines (left foreground) and the epiphytic Asplenium sp. ferns (center and right center) which were common in the forest. Photo by A. Allison.