Cyrtodactylus robustus Kraus, 2008, sp. nov.
Creators: name: Kraus, Fred
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Gekkonidae
Cyrtodactylus
Cyrtodactylus robustus

description: Cyrtodactylus robustus sp. nov.
Fig. 1 C
Holotype. BPBM 19735 (field tag FK 10445), mature male, collected by native collectors for F. Kraus along Wabu River, N slope Mt. Rossel, 11.34194ºS, 154.21921ºE, 320 m, Rossel Island, Milne Bay Province, Papua New Guinea, 14 May 2004.
Paratypes. Papua New Guinea: Milne Bay Province: Rossel Island: along Wabu River, N slope Mt. Rossel, 11.34194ºS, 154.21921ºE, 320 m (PNGNM 25169–70); S slope Mt. Rossel, 11.35552ºS, 154.22459ºE, 720 m (BPBM 19727); along Rupu River, N slope Mt. Rossel, 11.33537ºS, 154.2247ºE, 280 m (BPBM 19728, 19731, 19737–38); along Wupu River, N slope Mt. Rossel, 11.33805ºS, 154.22385ºE, 280 m (BPBM 19729–30); Gobubob, N slope Mt. Rossel, 11.33535ºS, 154.22226ºE, 275 m (BPBM 19732); Vieli, N slope Mt. Rossel, 11.33662ºS, 154.22362ºE, 235 m (BPBM 19733); near Cheme, 11.32547ºS, 154.24023ºE, 55 m (BPBM 19734); Wabu River area, N slope Mt. Rossel, 11.3324275ºS, 154.2078754ºE, 200–500 m (BPBM 19736); Jinja, 0–100 m (AMNH 76734); Abaleti, 0–50 m (AMNH 76743); unspecified locality (AMNH 89374, MCZ 153072).
Diagnosis. A very large (127–161 mm) species of Cyrtodactylus having a single row of enlarged subcaudal scales; enlarged dorsal tubercles conical, keeled, ~5–7 times size of adjacent granules (Fig. 2 E), in 24–30 rows; lateral tubercles distinct, ~4–7 times size of adjacent granules and larger than scales of lateral skin fold, which contains tubercles; 38–50 midbelly scale rows; precloacal/femoral pores 75–85, in a single continuous row; lamellae under fourth toe 25–32; head rather wide (HW/HL = 0.69–0.84, mean 0.77); four or five dark dorsal bands between head and hindlimb insertion, of more-or-less even width, margined in black, with 5–10 tubercles sagitally through 3rd dark band; dark spots usually present on light dorsal ground color; venter densely speckled with dark brown; mouth and cloacal linings burnt orange; and posterior supralabials dirty white.
Comparisons with other species. Cyrtodactylus robustus sp. nov. is distinguished from all other Papuan members of the genus except C. aaroni, C. mimikanus, C. murua, C. tuberculatus, C. salomonensis, C. louisiadensis, C. klugei sp. nov., and C. tripartitus sp. nov. by its single row of enlarged subcaudals. From C. aaroni and C. mimikanus it is distinguished by its much larger size (SV = 127–161 mm vs. 70–86.5 mm in C. aaroni and 67–103 in C. mimikanus), greater number of precloacal/femoral pores (75–85 vs. 17–27 in C. aaroni and <40 in C. mimikanus) in a single series (vs. three discrete patches), and fewer dark dorsal bands between the head and hindlimbs (4–5 vs. 8–11 in C. aaroni and C. mimikanus). From C. murua it is distinguished by having lateral tubercles larger than scales of lateral skin fold (vs. of equal size in C. murua), a greater number of dorsal tubercles (24–30 rows vs. 20–22 in C. murua), a greater number of lamellae under the fourth toe (25–32 vs. 24–25 in C. murua), wider head (HW/HL = 0.69–0.84 vs. 0.67–0.69 in C. murua), and dorsal bands of approximately equal width to intervening ground color (vs. wider in C. murua), and of even width across dorsum (vs. broadening medially in C. murua). From C. tuberculatus it is distinguished by its larger size (SV = 127–161 mm vs. 80–89 mm in C. tuberculatus), greater number of mid-belly scale rows (38–50 vs. 27–36 in C. tuberculatus), greater number of precloacal/femoral pores (75–85 vs. 36–46 in C. tuberculatus), in having lateral tubercles larger than scales of lateral skin fold (vs. of equal size in C. tuberculatus), and by having fewer dark dorsal bands (4–5 vs. 6–7 in C. tuberculatus). From C. salomonensis it is distinguished by its greater number of mid-belly scale rows (38–50 vs. 34–39 in C. salomonensis), greater number of precloacal/femoral pores (75–85 vs. 63–67 in C. salomonensis), fewer dark dorsal bands (4–5 vs. 6–7 in C. salomonensis) having even (vs. irregular in C. salomonensis) margins, usually having (vs. lacking in C. salomonensis) dark spotting in the light dorsal ground color, and venter densely speckled with dark brown (vs. uniform gray to yellow in C. salomonensis). From C. louisiadensis it differs in having conical, keeled dorsal tubercles (vs. flat and unkeeled in C. louisiadensis) of larger size (~5–7 times size of adjacent granules vs.
~2–3 times in C. louisiadensis); lateral tubercles large (~4–7 times size of adjacent granules vs. ~2–3 times in C. louisiadensis), larger than (vs. approximately equal size in C. louisiadensis) scales of lateral skin fold; a greater number of lamellae under the fourth toe (25–32 vs. 24–26 in C. louisiadensis); dark spots present in the dorsal ground color (vs. absent in C. louisiadensis); and posterior supralabials dirty white (vs. brown in C. louisiadensis). From C. klugei it differs in its larger dorsal tubercles (~5–7 times size of adjacent granules vs. ~4–5 times in C. klugei) arrayed in a greater number of rows (24–30 rows vs. 20–23 in C. klugei), greater number of precloacal/femoral pores (75–85 vs. 66–76 in C. klugei), somewhat wider head (HW/HL = 0.69– 0.84, mean 0.77 vs. 0.65–0.73, mean 0.70 in C. klugei), wider dark crossbands (with 5–10 tubercles sagitally through 3rd dark band vs. 5–6 in C. klugei), and dark spots present (vs. absent in C. klugei) on light dorsal ground color. From C. tripartitus it differs in its larger dorsal tubercles (~5–7 times size of adjacent granules vs. ~4–5 times in C. tripartitus), larger lateral tubercles (~4–7 times size of adjacent granules vs. ~4 times in C. tripartitus), more precloacal/femoral pores (75–85 vs. 64–78 in C. tripartitus) in a single series (vs. in three discrete patches in C. tripartitus), and in having (vs. lacking) dark spots in the light dorsal ground color. Cyrtodactylus robustus appears to differ from all other species in the complex in having the epithelial linings of the mouth and cloaca orange instead of pink.
Description of holotype: A mature male. Animal large (SV = 143 mm, TrL = 62.4 mm); tail folded back on itself and unamenable to accurate measurement, shorter than SV. Head relatively long (HL/SV = 0.30) and wide (HW/HL = 0.75), not depressed (HH/HL = 0.45), distinct from neck. Loreal region slightly inflated; canthus rostralis poorly defined. Interorbital region and top of snout concave. Snout relatively long (SN/HL = 0.39), much longer than eye diameter (SN/EY = 1.7). Eye relatively large (EY/HL = 0.23); pupil vertical, with weakly crenellated margins; supraciliaries large, frill-like, well-differentiated from adjacent granules. Ear opening large (Ear/HL = 0.12), depressed; distance between ear and eye larger than eye diameter. Rostral wider (6.8 mm) than high (4.2 mm), highest just medial to nares, lower between these points; length 1.9 mm; dorsal half divided by weak medial groove, with an azygous scale below this and contained within the center of the rostral. Two enlarged supranasals separated by two internasals. Rostral in contact with first supralabials, two supranasals, nasal, and two internasals. External nares circular; right bordered by rostral, two supranasals, first supralabial, and five postnasals. Circa eight rows of small scales separate orbit from supralabials at narrowest point. Mental triangular, wider (6.2 mm) than long (4.3 mm). Mental bordered posteriorly by two elongate postmentals. Infralabials bordered by slightly enlarged, elongate scales that gradually decrease in size posteriorly. Supralabials to mid-orbital position ten on right side, nine on left; to angle of jaw 14 on each side. Infralabials ten on each side.
Body robust (TrL/SV = 0.44), with lateral skin folds consisting of granules and small tubercles. Dorsal scales on head, body, and limbs tiny, juxtaposed granules, each with small raised asperities. Conical tubercles present on head, body, and limbs; best developed posteriorly; 5–6 times size of adjacent granules; distinct from granules in profile. Dorsal tubercles usually keeled, those on head and sides of body generally unkeeled. Tubercles arranged in approximately 26 rows between the lateral folds. Ventral scales flat and smooth; those on chin and throat smaller and juxtaposed, but heterogeneous in size, with several scales 3–5 times size of adjacent granules; those on abdomen larger and subimbricate, arrayed in 49 rows across mid-venter.
Precloacal and femoral pores 76, in a single continuous series. Scales of precloacal and femoral regions of approximately uniform size and not distinct from those on abdomen; scales on posterior femoral region smaller, one-third to one-half size of precloacal scales. No precloacal groove. Scales on palms and soles rounded, smooth.
Fore- and hindlimbs well-developed (FA/SV = 0.14, CS/SV = 0.17). Digits well-developed, reflected at basal interphalangeal joints; all with robust, recurved claws surrounded by two scales. Subdigital lamellae narrow and smooth, expanded proximally. Lamellae of manus 19–26–29–28–25 on right, 21–24–28–28–27 on left; of pes 21–25–29–30–28 on right, 22–26–30–27–27 on left. Relative lengths of digits on manus I <V <II <IV <III; on pes I <II <V <III <IV. Slight interdigital webbing on manus and pes.
Tail with final 3.3 cm regenerated, with rather narrow base (TW/SV = 0.080), tapering to a blunt point, with single row of enlarged subcaudals until regenerated portion. Cloacal sacs swollen, with small external orifices situated near lateral margins of vent; midventral scales of sac not distinctly larger than those ventrolaterally. Scales of tail small, flat, smooth, subimbricate; with approximately ten rows of enlarged dorsal tubercles just behind cloacal sacs, diminishing and then disappearing distally; one (left) or two (right) enlarged postcloacal spurs on sides of tailbase.
Color in preservative: Dorsal ground color medium chocolate brown; with dark chocolate brown chevron on nape whose anterior arms enter posterior border of eye; four more dark chocolate brown bands to region between hindlimbs; five more on tail, and regenerated portion also dark chocolate brown. Dark dorsal bands of approximately even width across dorsum, but slightly wider mid-dorsally, each marked by dark brown margins, these in turn bordered externally by light margins. Small dark brown spots scattered throughout light dorsal ground color. Tubercles same color as surrounding granules. Labials mottled dirty white and brown, contrasting with face. Venter mostly composed of purple-brown scales, heavily peppered with dirty white scales. Palms and soles brown, lamellae dark yellow.
Measurements (in mm). SV = 143, TrL = 62.4, TW = 11.4, FA = 20.7, CS = 23.7, HL = 42.3, HW = 31.8, HH = 19.1, Ear = 5.1, EE = 12.1, EY = 9.7, SN = 16.7, EN = 13.8, IN = 6.1, IO = 13.2.
Color in life. Field notes for BPBM 19727 (Fig. 1 C) note the color in life to be as follows: “Dorsum with four broad chocolate brown bands with irregular edges. Interspaces lighter brown with dark brown spots; limbs same. Venter light yellow brown with heavy peppering of dark brown scales on chest and belly and under limbs. Several dark brown spots on chin and throat. Iris light brown. Tongue pale peach with a pink tip. Cloacal lining burnt orange. Lamellae and palms gray, soles black. Chocolate brown bands edged with darker brown spots and also contain darker brown spots internally. No light edging to dark bands.” Color photos of this specimen also show it to have a number of scattered white tubercles on the sides and limbs. One specimen (BPBM 19728) was noted to have a darker brown iris and some cream tubercles on the side. Other specimens were noted to have the venter and sides washed with ochre. The venter of most specimens is most aptly described as ochre and mauve, with one color predominating in some specimens, and the second in others. Two additional specimens (BPBM 19732–33) were noted to have the tongue colored peach and pink, while a third had only a pale pink tongue (BPBM 19731). The cloacal linings of all were noted to be either burnt orange or bright yellow orange in color. Irises of all were rich brown but rarely as light as seen in BPBM 19727.
Variation. The type series of 18 specimens includes ten adult males varying in SV from 127–161 mm, seven adult females varying from 133–153 mm, and one juvenile female of 91 mm. Mensural data for the type series are summarized in Table 3. Supralabials to center of eye vary from 7–11, to angle of jaw 10–17. Infralabials vary from 9–13, fourth toe lamellae 25–32, mid-belly scale rows 38–50, and number of rows of dorsal tubercles 24–30. Numbers of precloacal/femoral pores vary from 75–85.
Ground color varies from dark tan to dark chocolate brown; a couple specimens have a dark orange cast to the dorsum. Color pattern includes either four (n = 7) or five (n = 11) dark dorsal bands (including the nuchal chevron), all of which have black edges that are further margined in light tan. These margins often appear erose because they may be broken. The dark bands contrast well with the lighter ground color in all except the darkest specimens. Most specimens clearly have small dark spots or blotches scattered in the light ground color, but spots may not be apparent in those specimens with the darkest ground color. Venters are typically dirty white or light purple-brown and heavily speckled with darker purple-brown, giving the venter a characteristically freckled appearance. One specimen (BPBM 19734), however, has a virtually uniformly light yellow-white venter. Posterior supralabials are white mottled with purple-brown; in a few cases, the purplebrown color predominates.
Etymology. The trivial epithet is a Latin masculine adjective meaning “strong like an oak” and is in reference to the large size and stout habitus of the species.
Range. Known only from Rossel Island, Milne Bay Province, Papua New Guinea (Fig. 3, inverted triangle).
Ecology. This species occurred commonly in primary and secondary rainforest. Animals occupied both lowland rainforest at elevations from 50–320 m elevation and cloud forest at 720 m. The species likely ranges across the entire elevational extent of the island, which attains only 838 m elevation. Animals were found active at night on tree trunks, limbs, and boulders, but they were wary and difficult to approach. One animal was removed from a tree cavity by day. I found the species to occur syntopically with the geckos Gekko vittatus, Nactus acutus Kraus, and two undescribed species of Nactus, and it may occur syntopically with Gehyra mutilata, G. oceanica, and Lepidodactylus lugubris, which also occur on Rossel Island.
description: Published as part of Kraus, Fred, 2008, Taxonomic partitioning of Cyrtodactylus louisiadensis (Lacertilia: Gekkonidae) from Papua New Guinea, pp. 1-27 in Zootaxa 1883 on pages 16-19, DOI: 10.5281/zenodo.184270