Adult male ZMKU R 00949 from Thung Na Ngam Subdistrict, Lan Sak District, Uthai Thani Province, Thailand (15.37649°N, 99.63426°E, 106 m a.s.l.), collected by Attapol Rujirawan, Siriporn Yodthong, Korkhwan Termprayoon, and Natee Ampai on 18 June 2018.

Cyrtodactylusuthaiensis sp. nov. can be separated from all other species of the brevipalmatus group by the combination of having 13–15 supralabials, 10–11 infralabials, 33 paravertebral tubercles, 17 rows of longitudinally arranged tubercles, 36 transverse rows of ventrals, 159 longitudinal rows of ventrals, eight expanded subdigital lamellae on the fourth toe, 12 unexpanded subdigital lamellae on the fourth toe, 20 total subdigital lamellae on the fourth toe; seven expanded subdigital lamellae on the fourth finger, 11 unexpanded subdigital lamellae on the fourth finger, 18 total subdigital lamellae on the fourth finger; 16 total enlarged femoral scales, 12 total femoral pores; 14 enlarged pore-bearing precloacals; enlarged femorals and enlarged precloacals not continuous; proximal femorals less than one-half the size of the distal femorals; small tubercles on forelimbs and flanks; large dorsolateral caudal tubercles and wide ventrolateral caudal fringe; ventrolateral caudal fringe composed scales of different size; tail circular in cross-section; slightly enlarged medial subcaudals intermittent, medially furrowed, posteriorly emarginated; maximum SVL 58.1 mm; and six dark transverse body bands (Tables 5, 6).

(Fig. 12). Adult male SVL 58.1 mm; head moderate in length (HL/SVL 0.28), width (HW/HL 0.68), depth (HD/HL 0.39), distinct from neck, triangular in dorsal profile; lores concave slightly anteriorly, weakly inflated posteriorly; prefrontal region slightly concave; canthus rostralis rounded; snout elongate (ES/HL 0.40), rounded in dorsal profile; eye large (ED/HL 0.29); ear opening elliptical, small; eye to ear distance greater than diameter of eye; rostral rectangular, dorsally furrowed, bordered posteriorly by large left and right supranasals, bordered laterally by first supralabials; external nares bordered anteriorly by rostral, dorsally by large supranasal, posteriorly by two smaller postnasals, ventrally by first supralabial; 13R/15L rectangular supralabials tapering smoothly to posterior margin of eye; 10R/11L infralabials tapering smoothly to posterior margin of eye; scales of rostrum and lores flat to domed, slightly larger than granular scales on top of head and occiput; scales of occiput intermixed with distinct, small tubercles; superciliaries subrectangular, largest dorsally and anteriorly; mental triangular, bordered laterally by first infralabials and posteriorly by large left and right trapezoidal postmentals contacting medially for approximately 40% of their length posterior to mental; one row of slightly enlarged, elongate sublabials extending posteriorly to fifth(L) and seventh(R) infralabial; gular and throat scales small, granular, grading posteriorly into slightly larger, flatter, smooth, imbricate, pectoral and ventral scales.

Body relatively short (AG/SVL 0.46) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with larger, conical, semi-regularly arranged, weakly keeled tubercles; tubercles extend from occipital region onto base of tail and slightly beyond as paravertebral rows; smaller tubercles extend anteriorly onto nape and occiput, diminishing in size anteriorly; approximately 17 longitudinal rows of tubercles at midbody; approximately 33 paravertebral tubercles; small tubercles on flanks; 36 longitudinal rows of flat, imbricate, ventral scales much larger than dorsal scales; 159 transverse rows of ventral scales; 16 total large femoral scales; 12 total femoral pores; 14 enlarged pore-bearing precloacals; no deep precloacal groove or depression; and two rows of post-precloacal scales on midline.

Forelimbs moderate in stature, relatively short (ForL/SVL 0.14); granular scales of forearm slightly larger than those on body, interspersed with large tubercles; palmar scales rounded, slightly raised; digits well-developed, relatively short, inflected at basal interphalangeal joints; digits narrower distal to inflections; subdigital lamellae wide, transversely expanded proximal to joint inflections, narrower transverse lamellae distal to joint inflections; claws well-developed, claw base sheathed by a dorsal and ventral scale; 7R/7L expanded and 11R/11L unexpanded lamellae beneath the fourth finger; hind limbs larger and thicker than forelimbs, moderate in length (TibL/SVL 0.14), covered dorsally by granular scales interspersed with moderately sized, conical tubercles dorsally and posteriorly and anteriorly by flat, slightly larger, subimbricate scales; ventral scales of thigh flat, subimbricate, larger than dorsals; subtibial scales flat, imbricate; one row of 6R/6L of enlarged pore-bearing femoral scales not continuous with enlarged pore bearing precloacal scales, terminating distally at knee; 8R/8L enlarged femoral scales; proximal femoral scales smaller than distal femorals, the former forming an abrupt union with much smaller, rounded, ventral scales of posteroventral margin of thigh; plantar scales flat; digits relatively long, well-developed, inflected at basal interphalangeal joints; 8R/(broken)L wide, transversely expanded subdigital lamellae on fourth toe proximal to joint inflection that extend onto sole, 12R/(broken)L unexpanded lamellae beneath first toe; and claws well-developed, sheathed by a dorsal and ventral scale at base.

Tail original, long 76.7 mm (TL/SVL 1.32), 4.1 mm in width at base, tapering to a point; sub-circular or nearly round in cross-section; dorsal scales flat, square bearing tubercles forming paravertebral rows and large tubercles forming a dorsolateral longitudinal row; slightly larger, posteriorly directed, semi-spinose tubercles forming small but distinct ventrolateral caudal fringe; larger scales of ventrolateral fringe occur at regular intervals; slightly enlarged medial subcaudals intermittent, medially furrowed, posteriorly; single enlarged medial subcaudals absent; subcaudal scales, larger than dorsal caudal scales; base of tail bearing hemipenial swellings; 3R/3L conical postcloacal tubercles at base of hemipenial swellings; and postcloacal scales flat, imbricate.

(Fig. 12). Ground color of the head, body, limbs, and tail pale-brown; dark, diffuse mottling on interorbital region and snout; dark blotch on top of head; wide, pale-colored postorbital stripe irregularly edged in dark brown extends from posterior margin of one eye across nape to posterior margin of other eye; ventral portion of lores, suborbital region, and supralabials darkly mottled; wide, dark brown nuchal band, bearing two posterior projections; six irregularly shaped darkly edged body bands extending between forelimb and hind limb insertions followed by one dark sacral band; paired dark brown paravertebral blotches on nape; band interspaces bearing irregularly shaped, dark-colored markings; dark-colored speckling on limbs and digits; digits bearing pale-colored bands; seven wide dark-colored caudal bands separated by six pale-colored bands; caudal bands encircle tail resulting in heavily mottled subcaudal region; all other ventral surfaces beige, generally immaculate; and iris gold in color.

Cyrtodactylusuthaiensis sp. nov. is currently known from the type locality at Thung Na Ngam Subdistrict, Lan Sak District, Uthai Thani Province, Thailand.

The specific epithet uthaiensis refers to the type locality, Uthai Thani Province, Thailand.

Cyrtodactylusuthaiensis sp. nov. is the sister species to a clade comprised the sister species C.interdigitalis and C. sp.11 (Fig. 2). Together, these taxa form the sister lineage to C.cf.ngati1, C.cf.ngati2, and all other C.ngati. Cyrtodactylusuthaiensis sp. nov. differs from those lineages by an uncorrected pairwise sequence divergence of 5.81–8.13% (Table 2). We are aware that any comparison based on morphometric and meristic characters are preliminary being that there is only one sample of Cyrtodactylusuthaiensis sp. nov. and that additional sampling may preclude some characters and being diagnostic just as it may reveal that other characters are diagnostic (see Table 5). Therefore, at this point we rely on the invariable categorical characters to separate Cyrtodactylusuthaiensis sp. nov. from other species in the brevipalmatus group. Cyrtodactylusuthaiensis sp. nov. differs from C.brevipalmatus, Cyrtodactylusfluvicavus sp. nov., C.interdigitalis, C.ngati, C.ngati3, C.cf.ngati1, C.cf.ngati2, C.rukhadeva, C.cf.rukhadeva and C. sp.13 by having large dorsolateral caudal tubercles (DCT) forming a wide ventrolateral caudal fringe (VLF1). Cyrtodactylusuthaiensis sp. nov. is further differentiated from C.ngati3, C.cf.ngati1, C.cf.ngati2, C.interdigitalis, C.rukhadeva, C.cf.rukhadeva, and sp.13 by having a ventrolateral fringe not homogenous (VLF2). It differs from Cyrtodactyluskochangensis sp. nov., Cyrtodactylusrivularis sp. nov., C.rukhadeva, C.cf.rukhadeva, and C. sp.11 by having tail that is more circular in cross-section than square (TLcross). From Cyrtodactylusrivularis sp. nov., C.rukhadeva and C.cf.rukhadeva, it differs by having enlarged, unmodified, medial subcaudal scales (SC1). From Cyrtodactylusrivularis sp. nov., C.rukhadeva and C.cf.rukhadeva, it differs by lacking single, enlarged, medial subcaudal scales (SC2). From all species in the brevipalmatus group except C.interdigitalis it differs by having posteriorly emarginated, medial subcaudals bearing a median furrow (SC3).

Cyrtodactylusuthaiensis sp. nov. is the only species of the brevipalmatus group that occurs in an isolated hilly area within the Chao Phraya River Basin (Fig. 1). The holotype (ZMKU R 00949) was collected at night (2055 h) on a bamboo twig approximately 170 cm above ground level at 106 m elevation. The habitat was isolated karst formations within a mixed deciduous forest. This area was surrounded by agricultural fields (plantations and rice fields) and human residential areas (Fig. 13). The new species was found to co-occur with a gekkonid lizard, Dixoniussiamensis (Boulenger, 1899).