Cyrtodactylus limajalur, 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 : 341-347

Cyrtodactylus limajalur sp. nov.

Five-banded Bent-toed Gecko

Holotype ( Fig. 5 ). Adult male, CAS 262848 collected near Kampung Tubih Mawang , Serian, Sarawak, East Malaysia. (01°17'47.62"N; 110°26'33.00"E; 88 m; WGS 1984 ) by Izneil Nashriq and Hayden Davis on August 06, 2017 at 20:00–22:00 hrs ( Fig. 1 ).

Paratypes. Paratypes ( CAS 262846 ; CAS 262847 ; and CAS262849 ) ( Fig. 5 ) have the same collection data as the holotype .

Diagnosis. Cyrtodactylus limajalur sp. nov. can be differentiated from all other species of Cyrtodactylus by the combination of the following characters: maximum SVL of at least 94 mm; 10–12 supralabials; 9–11 infralabials; weak tuberculation on body; no tubercles on ventral surface of forelimbs, gular region, or ventrolateral folds; 34–38 paravertebral tubercles; 11–13 longitudinal tubercle rows; 33–42 ventral scales; 19–22 subdigital lamellae on fourth toe; 5–6 enlarged femoral scales; no femoral pores; 7–8 precloacal pores; precloacal pit in males; enlarged median row of transverse scales; 5 dark dorsal body bands; body bands more than two times the width of interspaces; rostral chevron just posterior to orbitals; no white line edging the body bands and nuchal loop; and no scattered white tubercles on dorsum. These characters are scored across all currently recorded Bornean Cyrtodactylus species in Table 3.

Description of holotype. Adult male; 90.8 mm SVL; head large, moderate in length (HL/SVL 0.28), relatively narrow (HW/HL 0.46), moderately flattened (HD/HL 0.36), 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 0.27); ear opening elliptical, moderate in size (EL/HL 0.10), obliquely oriented; eye to ear distance less than diameter of eye; rostral scale rectangular, partially divided dorsally by line extending from the posteriormost portion of the rostral scale to approximately half the distance anteriorly, two postnasal scales, one medial postrostralis (internasal), bordered laterally by first supralabials; external nares bordered anteriorly by rostral, ventrally by first supralabial; 12/10 (L/R) rectangular supralabials extending to the upturn of the labial margin, tapering abruptly directly below midpoint of eye; first supralabial largest; 9/11 (L/R) infralabials extending to the upturn of the labial margin, tapering abruptly directly below midpoint of eye; 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; 38/34 (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 40% of their length, forming a Y-shape; 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 smooth 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 13 longitudinal rows of tubercles slightly posterior of midbody; 38 paravertebral tubercles; 42 flat imbricate ventral scales between ventrolateral body folds; ventral scales larger than dorsal scales; precloacal scales with 5/3 (L/R) pores, slightly larger than ventral scales; shallow precloacal pit.

Forelimbs relatively short (FL/SVL 0.17); scales on preaxial surface of forelimbs small, tubercles absent; scales on postaxial surface flat, tubercles absent; palmar scales weakly rounded; digits well developed, inflected at basal interphalangeal joints; 22/21 (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; 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; ventral tibial scales flat, smooth; 8/6 (L/R) expanded femoral scales; expanded precloacal scales; 7 pore-bearing precloacal scales; precloacal scales expanded, forming pit; plantar scales slightly raised; digits well developed, inflected at basal, interphalangeal joints; 20/21 (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 regenerated from base, 114.0 mm long, 6.6 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 3/2 (L/R) cloacal spurs.

Coloration in life. Dorsum of head, body, limbs, and tail greyish-brown; V-shaped line on rostrum; wide darkbrown nuchal loop that extends to the tip of the snout, edged by white line; five dark-brown bands between nuchal loop and the posterior portion of the limb insertion, edged anteriorly and posteriorly by thin dark-brown lines; body bands at least two times wider than interspaces; front limbs with light-brown blotch pattern; hind limbs with two dark bands separated by white interspaces; ventral portion of body bearing uniform light cream color; tail regenerated bearing four white spots on the anterior half, light grey dorsal and ventral coloration.

Variation. The paratypes are very similar to the holotype in coloration and pattern (Table 4). CAS 262846 and CAS 262847 displays reduced dorsal tuberculation, particularly on the anterior half of the body; CAS 262849 has one less precloacal pore with 4/3 (L/R), a less well-defined rostral V-pattern, and no chevron posterior to the orbitals ( Figs. 5 & 6 ).

Distribution. Cyrtodactylus limajalur sp. nov. is only known from an isolated karst massif in the greater Serian area in southwestern Sarawak. The Serian area has a high concentration of large, isolated karst massifs ( Wilford, 1964). Cyrtodactylus limajalur sp. nov. was collected from a karst massif approximately one kilometer from a main road. Surrounding formations were not sampled due to inaccessibility, indicating the possibility that this species inhabits other surrounding karst formations ( Fig. 4 ).

Etymology. The specific epithet limajalur is in reference to the banding pattern of the species. “Lima jalur” loosely translated from Malay is five-banded. Cyrtodactylus limajalur sp. nov. has a very distinct banding pattern that is consistently comprised of five bands. This species is the first Bornean Cyrtodactylus species that displays a consistent banding pattern, without blotches or other markings.

Natural history. All specimens of Cyrtodactylus limajalur sp. nov. were collected between 19:00 and 22:00 hours on large karst boulders at the base of a large limestone face. No female specimens were gravid. They occur sympatrically with Cyrtodactylus consobrinus and C. pubisulcus , however, C. consobrinus was seen almost exclusively on large tree trunks and C. pubisulcus was only found on low-lying vegetation, indicating that they may not be syntopic with C. limajalur sp. nov.

There were no noticeable cave entrances on the karst massif. All specimens were collected within approximately ~ 5 m 2 of each other, however, there did not appear to be anything different or significant about that specific location.

All of the specimens comprising the type series had regenerated tails. However, the tails were all fully regenerated indicating that the species may experience higher rates of predation at earlier stages in life.

Comparison. Cyrtodactylus limajalur sp. nov. differs from all its Bornean congeners by one or more morphological characteristics. The new species is distinguished from C. baluensis by having a distinct banding pattern as opposed to bands and blotches; it is distinguished from C. cavernicolus by having a lower number of ventral scales (33–42 versus 51–58), enlarged subcaudals, and a precloacal pit as opposed to a precloacal groove; it is distinguished from C. consobrinus by having a smaller adult maximum SVL (94 mm versus 125 mm), and no white reticulated pattern on occiput; it is distinguished from C. ingeri by having a precloacal pit as opposed to no depression, 5–6 enlarged femoral scales as opposed to none, and a distinct banding pattern as opposed to bands and blotches; it is distinguished from C. malayanus by having no tubercles on the upper arm, and a lower number of ventral scales (33–42 versus 58–62); it is distinguished from C. matsuii by having enlarged subcaudals, 5–6 enlarged femoral scales as opposed to none, and a smaller maximum SVL (94 mm versus 105 mm); it is distinguished from C. pubisulcus by having enlarged subcaudals, 5–6 enlarged femoral scales as opposed to none, and a precloacal pit as opposed to a precloacal groove; and it is distinguished from C. yoshii by having no tubercles on the upper arm, a lower number of ventral scales (33–42 versus 50–58), a lower number of subdigital lamellae (19–22 versus 25–30), and 5–6 enlarged femoral scales as opposed to none.

Phylogenetic analyses. The ML tree shown herein corroborates the morphological data distinguishing the two lineages as new species ( Fig. 7 ). The ML analysis places both C. limajalur sp. nov. and C. muluensis sp. nov. in separate deeply divergent clades with both being distinct from C. cavernicolus sensu stricto, as previously suggested. Cyrtodactylus muluensis sp. nov. is well supported as the sister species to C. pubisulcus sensu stricto, another Bornean endemic. Furthermore, C. muluensis sp. nov. is embedded within the monophyletic group of primarily Philippine endemics, including C. philippinicus , C. redimiculus , C. jambangan , C. tautborum , and the C. agusanensis species complex. Nodal support is lacking for some of the noted relationships: C. pubisulcus and C. baluensis as outgroups to the monophyly containing C. muluensis sp. nov.; C. redimiculus as the nearest outgroup to the C. muluensis sp. nov., C. pubisulcus sensu stricto, C. aurensis , and C. cavernicolus monophyly; and the sister clade relationship between the C. muluensis sp. nov. group and the C. agusanensis clade; but there is strong support for the deepest node forming the Philippine clade. The phylogeny has strong support (92/1.00) for designating C. muluensis sp. nov. as a distinct lineage. The two subclades demonstrated within the C. muluensis sp. nov. clade correlate with the karst formation in which they were found in. The clade comprised of specimens CAS 262995–262997 originated from the karst formation around the Clearwater Cave, and the specimens in the other subclade were from the karst formation around the Lang Cave. No morphological differences were found between the individuals in the two subclades

Cyrtodactylus limajalur sp. nov. forms a clade that is well supported (99/0.99) as the sister species to the C. consobrinus / malayanus group. While these latter two species are difficult to distinguish from one another morphologically (Hikida 1991; references therein), they are well-supported as phylogenetically distinct lineages based on the concatenated dataset. Regardless, C. limajalur sp. nov. has strong support for its designation as a new species.

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 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.

FIGURE 5. Preserved type series of Cyrtodactylus limajalur sp. nov.; A) type series displaying dorsal side of body (from left to right: CAS 262849; CAS 262848; CAS 262847; and CAS 262846); and B) type series displaying ventral side of body (specimens arranged in the same order as figure 5A).

FIGURE 6. Photograph of live paratype of Cyrtodactylus limajalur sp. nov. (CAS 262846).

FIGURE 7. ML tree of Bornean Cyrtodactylus and their closely related congeners. Phylogenetic position of C. limajalur sp. nov. and C. muluensis sp. nov. is indicated by the purple and green boxes, respectively. Black circles at the node denote UF values of 95 or greater and posterior probabilities of 0.95 or greater. White circles at the node denote nodes at which either the UF or posterior probability demonstrated support, but not both.