Acanthosaura liui

Description of the holotype. Adult male. SVL 85.1 mm. TL 150.6 mm, tail complete. Head length 26.7 mm; head moderately long (HL / SVL 31 %), somewhat narrow (HW / SVL 22 %), not tall (HD / HL 57 %), triangular in dorsal and lateral profile. Snout short (SL / HL 40 %), a Y-shaped arrangement of enlarged scales on the snout; interorbital and frontal regions and rostrum wide. Canthus rostralis prominent, forming a large projecting shelf extending above eye, composed of 12 / 13 enlarged scales; shelf terminates with a notch anterior to the postorbital spine. Nasal concave, nostrils surrounded by a circular scale. Eye relatively large (EYE / HL 22 %), orbit very large (ORBIT / HL 31 %). Prefrontal and frontal scales slightly keeled and larger than scales between supralabials; scales on occiput weakly keeled. Moderately elongate epidermal spine above posterior margin of eye, straight, surrounded by 5 / 5 enlarged scales. A notch present between the supraciliary edge and postorbital spine. Moderately elongate epidermal spine on occipital region, straight, surrounded by a rosette of 5 / 5 short spiny scales. A row of enlarged conical scales present between orbit and occipital spine; a few elongate conical scales present on the posterior of lower jaw. Tympanum exposed, oblong, surrounded by small scales. Supralabials 10 / 11, rectangular, scales in center of series largest; infralabials 10 / 11, rectangular, scales in center of series largest; rostral oblong, eight scales contacting the rostral; mental squarish above, becoming triangular below, larger than first pair of infralabials, six scales contacting the mental; gulars sharply keeled and spinose. Dewlap extensible, gular pouch relatively developed. Nuchal crest composed of five elongate, lanceolate, laterally compressed scales bordered on each side by one row of enlarged, spinose scales; nuchal crest gradually developed posteriorly, the first nuchal crest spine shortest and the last nuchal crest spine longest; nuchal crest followed by a diastema at base of nape. Dorsal body crest underdeveloped, extending from posterior margin of diastema onto base of tail; vertebral crest composed of enlarged, epidermal, laterally compressed, spinose scales; vertebral crest tapers slightly to base of tail, then fades progressively. Body slightly short, triangular in cross-section. Dorsal scales small, mixed with large scales indistinctly arranged in diagonal rows, keels projecting posterior wards; scales of pectoral region and abdomen larger than dorsal scales, keeled, more or less arranged in transverse rows; keeled scales anterior to vent not enlarged. Limbs relatively long (FOREL / SVL 42 %, HINDL / SVL 60 %); dorsal and ventral scales of forelimbs keeled, spinose, approximately the same size. Five digits on manus; subdigital scales keeled, subdigital lamellae under fourth finger 17 / 17. Scales of hind limbs keeled and spinose; postfemoral scales small, interspersed with larger spinose scales. Five digits on pes; subdigital scales keeled, subdigital lamellae under fourth toe 25 / 25. Tail length 1.77 times SVL, tail covered with keeled spinose scales, keels on subcaudals directed posteriorly; subcaudals much longer than supracaudals; base of tail 12.3 mm wide.

Diagnosis. Body size medium (SVL 85.1 - 95.9 mm), postorbital and occipital spines present; relatively developed gular pouch; scales on flanks randomly intermixed with medium and large scales; nuchal crest gradually developed posteriorly, first nuchal crest spine shortest and last nuchal crest spine longest; diastema between nuchal and dorsal crests present; dorsal crest underdeveloped, composed of enlarged, pointed scales beginning at shoulder region and decreasing regularly in size; tail 1.47 - 1.77 x SVL; number of subdigital lamellae on the fourth finger 16 - 18 and the fourth toe 22 - 25; black nuchal collar present; black eye patch extending from nostril through orbit posteriorly and downwards through tympanum and then posteriorly and upwards meeting diamond-shaped black nuchal collar on nape; black oblique folds anterior to forelimb insertions present and not meeting black nuchal collar; anterior nuchal crest spines and dorsal sides of postorbital and occipital spines light colored, posterior nuchal crest spines and ventral sides of postorbital and occipital spines black; gular pouch light blue; tongue and inside of mouth yellow.

Distribution. After our extensive field investigation, Acanthosaura liui sp. nov. is only recorded in Jianshui County, Gejiu City, and Shiping County, Honghe Autonomous Prefecture, Yunnan, China.

Etymology. The specific epithet is dedicated to the renowned herpetologist Prof. Chengzhao Liu (30.9.1900 - 9.4.1976), in recognition of his great contributions to herpetological research in China.