This Arabian Spiny-tailed Lizard was found in Qaryat Al Ulya Pivot Field and had made its burrow in the soft ground where the plants were being planted. This is an unusual place to find them as they are normally associated with burrows in rough sandy gravel areas. The Lizard was a blue colour as it had not warmed up properly when they reach a bright yellow colour like the bottom photograph here taken in the summer of 2012 at Abqaiq on a tarmac road. Spiny-tailed Lizard (Uromastyx spp.) is a medium to large sized, heavily built lizard with a spiny club like tail, which has been likened to a small living dinosaur. They are ground dwelling and live in some of the most arid regions of the planet including northern Africa, the Middle East, Arabia, Iran, Iraq, Afghanistan, Pakistan and north-western India. The generic name (Uromastyx) is derived from the Ancient Greek words ourá (οὐρά) meaning "tail" and mastigo (Μαστίχα) meaning "whip" or "scourge", after the thick-spiked tail characteristic of the species. The Arabian Spiny-tailed Lizard (Uromastyx aegyptia microlepis) is most common in Saudi Arabia and is the one that occurs in the Eastern Province and is generally regarded as a subspecies of the Egyptian Spiny-tailed Lizard (Uromastyx aegyptia). It is locally known to the Arabs as 'Dhub' (Arabic:'ضب'). The main diagnostic character of the genus is the highly specialised tooth-like bony structure replacing the incisor teeth in the upper jaw in adults. The Arabian Spiny-tailed Lizard can be distinguished from Egyptian Spiny-tailed Lizard (Uromastyx aegyptia aegyptia) by lacking enlarged tubercular scales scattered over the scalation of the flanks, having 149‑193 (mean 171.8) ventral scales rather than 126 – 158 (mean 142). Other features include a smaller scale size and more colourful yellow or greenish colour when warmed-up in adult specimens of Arabian Spiny-tailed Lizard. It is distinguished from Uromastyx leptieni by a different juvenile colour pattern and a higher number of ventrals.
