Horsfield's Spiny Lizard (Salea horsfieldii) is a species of agama

Agamidae

Agamids, lizards of the family Agamidae, include more than 300 species in Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Phylogenetically they may be sister to the Iguanidae, and have a similar appearance. Agamids usually have...

found in southern India in the Nilgiri and Palni Hills.

Description

From C. A. L. Gunther (1864) The Reptiles of British India.

A series of scales between orbit and tympanum rather larger than the others on the side of the neck. The hind leg extends to, or nearly to, the angle of the mouth, if laid forwards. The middle of the trunk is surrounded by about thirty-eight series of scales. Dorsal crest high in the adult male, composed of long, closely set, lanceolate spines, a nuchal portion being separated from the dorsal portion by a very short interspace; it extends on to the tail; it is much less developed in immature males in its altitudinal and longitudinal extent, and remains rudimentary in the female sex. An irregular black band, edged below with white, is most distinct between the orbit and the tympanum; it is interrupted behind the ear and reappears before the shoulder-joint. The back is ornamented with irregular white and black cross bands—many white scales having a dark margin, and the black ones a red longitudinal streak. The isolated large scales arc white. Head with red and white dots above; spines of the dorsal crest partly black and partly red; legs with bands similar to those of the back; tail with broad brown rings. The females have less bright colours; and the young ones broad brown bands across the back, between a pair of indistinct light longitudinal bands running along the sides of the back.
This description of the colours is taken from drawings of living specimens in the possession of Walter Elliott, Esq. The coloration, however, appears to be very variable: Jerdon describes it as a bright grass-green marbled with brown, with some red marks on the head and nape and with a few white scales on the sides. The colours become darker at a low temperature, as is the case with many tropical lizards.

This is the only species known, the S. gularis of Blyth evidently belonging to a different genus. It is found in the Nilgherries and at Newera Ellia in Ceylon, where it frequents bushes and hedges. The statement of its occurrence in Afghanistan depends on a label found with the typical specimens in the former collection of the East India Company. It attains to a length of 15 inches, the tail measuring 11 inches.

Snout not more than once and a half as long as diameter of orbit, which equals about twice that of tympanum; upper head-scales large, rugose, with a more or lees marked curved series of regular ones bordering the supra-orbital region internally; a row of 3 or 4 enlarged scales from the eye to above the tympanum. Gular scales lanceolate, keeled, ending in a spine, as large as or a little larger than the ventrals. No fold in front of the shoulder. Nuchal crest in the male composed of a few lanceolate spines directed backwards, the longest measuring nearly the length of the snout, with smaller spines at the base; in the female this crest is reduced to a double row of alternate oblique short spines; dorsal crest not continuous with nuchal, composed of similar slightly shorter lanceolate spines in the male, absent in the female. Dorsal scales large, rhomboidal, strongly keeled, pointing straight backwards ; they are nearly always of unequal size, larger ones being scattered on the sides; ventral scales very strongly imbricate, strongly keeled and ending in a spine, nearly as large as the dorsals. Limbs moderately elongate, the adpressed hind limb reaching between the shoulder and the tympanum. Tail compressed and with a small upper crest in the male, scarcely compressed and without a crest m the female; caudal scales sub-equal, strongly keeled. Pale olive above, with irregular dark-brown cross bands, which may be broken up by a band of the light-brown colour running along each side of the back; the enlarged scales on the sides frequently white; a blackish band, edged below with white, extends from the eye to the fore limb, passing through the tympanum; tail usually with regular dark-brown annuli. From snout to vent 3.75 inches, tail 9.75.