Cyrtodactylus muluensis, Davis & Bauer & Jackman & Nashriq & Das, 2019

Davis, Hayden R., Bauer, Aaron M., Jackman, Todd R., Nashriq, Izneil & Das, Indraneil, 2019, Uncovering karst endemism within Borneo: two new Cyrtodactylus species from Sarawak, Malaysia, Zootaxa 4614 (2), pp. 331-352 : 333-341

Cyrtodactylus muluensis sp. nov.

Mulu Bent-Toed Gecko

Holotype ( Fig.1 ). Adult male, CAS 262983 collected from Lang Cave , Mulu National Park, Sarawak, East Malaysia. (04°1'34.34"N; 114°49'26.77"E; 155 m; WGS 1984 ), collected by Izneil Nashriq and Hayden Davis on July 21, 2017 at 20:00–22:00 hrs.

Paratypes. Paratypes ( CAS 262984 ; CAS 262986 ; ( Figs. 1 & 2 )) have the same collection data as the holotype . Paratypes CAS 262995–262997 were collected from the karst surfaces situated between Clearwater Cave and Long Cave (04°3'47.048"N; 114°49'50.60"E; 205 m; WGS 1984 ) , on July 23, 2017.

Diagnosis. Cyrtodactylus muluensis sp. nov. can be differentiated from all other species of Cyrtodactylus by the combination of the following characters: maximum SVL of at least 88 mm; 10–13 supralabials; 8–11 infralabials; weak tuberculation on body; no tubercles on ventral surface of forelimbs, gular region, or ventrolateral folds; 33–54 paravertebral tubercles; 13–15 longitudinal tubercle rows; 33–42 ventral scales; 19–22 subdigital lamellae on fourth toe; 5 femoro-precloacal pores; enlarged median row of transverse scales; shallow precloacal groove in males; 5–8 dark dorsal body bands; body bands as wide as or slightly wider than interspaces; no rostral chevron; no white line edging the body bands and nuchal loop; banding pattern on dorsal side of body; no scattered white tubercles on dorsum; and nine dark caudal bands on original tail. These characters are scored across all currently described Bornean Cyrtodactylus species in Table 3.

Description of holotype. Adult male; 75.3 mm SVL; 98.6 mm TL; head large, moderate in length (HL/SVL 0.29), wide (HW/HL 0.62), slightly flattened (HD/HL 0.38), distinct from neck, triangular in dorsal profile; loreal scales slightly concave posteriorly, flat anteriorly; frontal and prefrontal regions concave; canthus rostralis rounded; snout elongate (ES/HL 0.44), rounded in dorsal profile, laterally constricted; eye large (ED/HL 0.25); ear opening elliptical, moderate in size (EL/HL 0.08), obliquely oriented; eye to ear distance greater than diameter of eye; rostral scale rectangular, divided dorsally by an inverted Y-shaped furrow, no postnasal scale, one medial postrostralis (internasal), bordered laterally by first supralabials; external nares bordered anteriorly by rostral, ventrally by first supralabial; 12 (L/R) rectangular supralabials extending to the upturn of the labial margin, tapering abruptly directly below midpoint of eye; first supralabial largest; 12 (L/R) infralabials extending to the upturn of the labial margin, tapering abruptly directly below midpoint of eye; rostral and loreal scales weakly raised, same size as scales on top of head, occiput, and canthus rostralis; no tubercles on occiput or interorbital region; bony ridge bordering the orbital rim; transverse frontoparietal ridge; 36/38 (L/R) supracilliary scales, elongate, smooth, largest anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by left and right rectangular postmentals which contact medially for approximately 40% of their length, forming a Yshape; single row of slightly enlarged, elongate chinshields extending posteriorly to sixth infralabial scale; small, flat gular scales gradually grading posteriorly into larger, flat, smooth pectoral and ventral scales.

Body with distinct, non-tuberculate ventrolateral folds; dorsal scales small, granular interspersed with low, regularly arranged keeled tubercles; small intervening tubercles occasionally present; tubercles extend from top of head to caudal constriction, and onto anterior one-fifth of tail; tubercles on occiput and nape small, those on posterior portion of body largest; approximately 15 longitudinal rows of tubercles slightly posterior of midbody; 43 paravertebral tubercles; 37 flat imbricate ventral scales between ventrolateral body folds; ventral scales larger than dorsal scales; precloacal scales smooth, slightly larger than ventral scales; moderately deep precloacal groove.

Forelimbs relatively short (FL/SVL 0.16); scales on preaxial surface of forelimbs small, tubercles absent; scales on postaxial surface flat, subimbricate, tubercles absent; palmar scales weakly rounded; digits well developed, inflected at basal interphalangeal joints; 19/18 (L/R) subdigital lamellae on fourth finger, rectangular, broadly expanded proximal to joint inflection, slightly expanded immediately distal to joint becoming gradually more expanded near the claw; claws well-developed, relatively short; hind limbs more robust than forelimbs, moderate in length (TBL/SVL 0.20); postaxial thigh scales flat, smooth, slightly larger than dorsal granular scales; postaxial tibial scales flat, smooth; expanded femoral scales absent; 3/2 (L/R) pore-bearing precloacal scales; precloacal scales expanded forming an inverted T bearing a moderately deep precloacal groove in which porebearing scales are absent; plantar scales slightly raised; digits well developed, inflected at basal, interphalangeal joints; 20 (L/R) subdigital lamellae on fourth toe rectangular, broadly expanded proximal to joint inflection, slightly expanded immediately distal to joint becoming gradually more expanded near the claw.

Tail original, 98.6 mm long, 5.9 mm wide at base, tapering to a point distally; dorsal scales flat, squarish; subcaudal region bearing enlarged median row of transverse scales; no caudal furrow; base of tail forming hemipenal swelling; and 4/6 cloacal spurs on left/right of hemipenal swelling, respectively, one tubercle substantially larger than the others on both sides.

Coloration in life. Dorsum of head, body, limbs, and tail greyish-brown; no V-shaped line on rostrum; wide dark-brown nuchal loop that extends to the tip of the snout, edged by white line; seven dark-brown bands between nuchal loop and the posterior portion of the hindlimb insertion, each edged anteriorly and posteriorly by thin darkbrown lines; body bands wider than interspaces; limbs with light-brown band/blotch pattern; ventral portion of body bearing uniform light cream color; tail bearing nine dark bands separated by nine, narrower grey bands dorsally, uniform beige coloration ventrally.

Variation ( Fig. 1 & 2 ). The paratypes are very similar to the holotype in coloration and pattern. In life, the coloration varied due to apparent substrate matching with those on karst bearing a light grey coloration with dark banding, and those on wood and vines bearing a light brown coloration with dark banding. Preserved, CAS 262985 displays lighter coloration than the holotype, with less well-defined banding, and little to no dark coloration on the top of the head; CAS 262985 displays darker coloration than the holotype. The juvenile specimen (CAS 262995) has white bands separating the dark bands on the tail, and tan coloration on the ventral surface of the body.

Distribution. Cyrtodactylus muluensis sp. nov. is known from the Clearwater Cave, Long Cave, and Lang Cave within Mulu National Park, Sarawak, East Malaysia. The Clearwater Cave and Long Cave are on the same karst peak ~ 1 km apart. The Mulu area has a high concentration of limestone karst formations, most of which were not surveyed over the course of our work ( Fig. 3 ).

Etymology. The specific epithet muluensis is in reference to the type locality, Gunung Mulu National Park. As this is the first endemic gekkonid described from Gunung Mulu, the name muluensis is fitting.

Natural history. All specimens of Cyrtodactylus muluensis sp. nov. were collected between 1900 and 2200 hours on karst surfaces and thin vines and branches ( Fig. 4 ). Lizards were found on both vegetation and karst walls, however, there was higher concentration near the cave openings, indicating that the species may find refuge inside of the caves during the daylight hours. All specimens were collected within 5 m of a karst structure. Only one specimen was collected from the inside of a cave; the specimen was approximately 10 m inside the cave entrance and 4 m up from the ground in the grooves of a stalagmite at Lang Cave. No female specimens were gravid; however, one hatchling was collected.

The expansive primary forest at Mulu National Park contains a high concentration of karst massifs. Gua Lang is located ~ 1 km from the Melinau Paku River. Clearwater Cave and Long Cave are on the river with the openings of each cave roughly 100 m from the riverbank.

The lizards were relatively common, especially on wooden walkways leading to the caves. They were quick to react when approached, and two of the specimens of the type series have regenerated tails. They occur sympatrically with Cyrtodactylus consobrinus (Peters) and C. cf. pubisulcus , however, C. consobrinus was seen almost exclusively on large tree trunks and C. cf. pubisulcus was almost exclusively on low-lying vegetation, indicating that they may not be syntopic with one another.

Comparison. Cyrtodactylus muluensis sp. nov. differs from all its Bornean congeners by one or more morphological characteristics. The new species is distinguished from C. baluensis (Mocquard) by having a precloacal groove as opposed to a precloacal pit, and a distinct banding pattern as opposed to bands and blotches; it is distinguished from C. cavernicolus by having a lower number of ventral scales (31–38 versus 51–58), fewer subdigital lamellae on the fourth toe (19–22 versus 22–26), and distinct dorsal bands as opposed to dorsal bands and blotches; it is distinguished from C. consobrinus by having a smaller adult maximum SVL (88 mm versus 125 mm), and no white reticulated pattern on occiput; it is distinguished from C. ingeri Hikida by having a precloacal groove as opposed to no depression, and a distinct banding pattern as opposed to bands and blotches; it is distinguished from C. malayanus (de Rooij) by having a lower number of ventral scales (33–42 versus 58–62), and no tubercles on the upper arm; it is distinguished from C. matsuii Hikida by having a lower maximum SVL (88 mm versus 105 mm), enlarged subcaudals, and a lower number of ventral scales (33–42 versus 48–51); it is distinguished from C. pubisulcus Inger by having a larger maximum SVL (88 mm versus 74 mm), and a distinct banding pattern as opposed to primarily blotches; and it is distinguished from C. yoshii Hikida by having fewer subdigital lamellae (19–22 versus 25–30), enlarged subcaudals, and a lower number of ventral scales (33–42 versus 50–58).

Figures

FIGURE 1. Preserved type series of Cyrtodactylus muluensis sp. nov. A) type series displaying dorsal side of body (from left to right: CAS 262995; CAS 262986; CAS 262983; CAS 262997; CAS 262996; and CAS 262984; CAS 262985 not shown); and B) type series displaying ventral side of body (specimens arranged in the same order as figure 1A).

FIGURE 2. Photographs of live individuals of Cyrtodactylus muluensis sp. nov. A) adult holotype (CAS 262983); B) juvenile paratype (CAS 262995).

FIGURE 3. Map of Eastern Malaysia with circles indicating the type locality of the three Bornean karst-dwelling Cyrtodactylus species. Map is an altered version of 2018 Google Earth, US Dept of State Geographer map.

FIGURE 4. A) Mulu karst formation demonstrating Cyrtodactylus muluensis sp. nov. microhabitat; B) type locality of Cyrtodactylus limajalur sp. nov. The type locality of C. muluensis sp. nov. is primarily old growth with low-lying plants near the karst walls; the type locality of C. limajalur sp. nov. is on the edge of a local palm oil plantation with some old growth remaining at the base of the karst wall and on the portions of the formation at higher elevation.