Gerrhosaurus intermedius Lönnberg, 1907

Pietersen, Darren W., Pietersen, Errol W. & Conradie, Werner, 2017, Preliminary herpetological survey of Ngonye Falls and surrounding regions in south-western Zambia, Amphibian & Reptile Conservation (e 148) 11 (1), pp. 24-43 : 32

Gerrhosaurus intermedius Lönnberg, 1907

Eastern Black-lined Plated Lizard

Photograph: VMUS 158887

A number of individuals suspected to be referable to G. intermedius were seen, however only a single individual was photographed and the scalation details later determined from this photograph ( Fig. 2f ). A narrow, pale dorsolateral line is present, bordered on each side by a dark line. A pale vertebral stripe, flanked on either side by a dark stripe, originates on the nape and extends to the base of the tail as discrete, evenly-spaced dashes. The frontonasal is divided into a large, heart-shaped anterior portion and a smaller posterior “inter-frontonasal,” which is in contact with the frontal thus separating the prefrontals. The dorsal scales are arranged in 22 longitudinal and approximately 56 transverse rows. The flank scales are keeled and weakly mucronate and the head length is contained in the body length approximately 4.14 times.

Despite the prefrontals being separated, this individual is distinguished from G. flavigularis by the presence of four supraciliaries, the keeled and weakly mucronate lateral scales, head length into snout-vent length ratio and coloration ( Bates et al. 2013; Branch 1998; FitzSimons 1943). It is distinguished from G. auritus by the number of longitudinal and transverse scale rows and the keeled and weakly mucronate lateral scales. We refer this individual to G. intermedius rather than G. nigrolineatus sensu stricto based predominantly on coloration. In G. nigrolineatus the dark stripes bordering the pale dorsolateral stripes are often ragged, while the pale vertebral stripe (and flanking dark stripes) may be continuous or absent, but are usually better-developed than in G. intermedius ( Bates et al. 2013) . When present, the dark markings surrounding the discontinuous vertebral stripe appear to be more extensive ( Bates et al. 2013; Hallowell 1857). This record is about 110 km NNW of the nearest previous reported locality at Sesheke ( Broadley 1971a).

Figures

Fig. 2. Selection of amphibians and reptiles photographed in the vicinity of Ngonye Falls, south-western Zambia. (A) View of Ngonye Falls from the eastern side of the Zambezi River. (B) Mapacha Grass Frog (Ptychadena cf. mapacha, VMUS 5990), Sioma Ngwezi National Park Headquarters. (C) Long-tailed Worm Lizard (Dalophia longicauda), Sioma Ngwezi National Park Headquarters.(D) Zambezi Rough-scaled Lizard (Ichnotropis grandiceps, TM 86237), Sioma Ngwezi National Park Headquarters. (E) Barotse Blind Legless Skink (Acontias jappi, TM 86232), Sioma Ngwezi National Park Headquarters. (F) Eastern Black-lined Plated Lizard (Gerrhosaurus intermedius), Sioma Ngwezi National Park Headquarters.