Whilst visiting Abqaiq to try to find the wetland areas that were present in this region in the 1980's I cam across a very bright yellow Arabian Spiny-tailed Lizard on the side of the road. After just avoiding running t over I turned the car around and the Lizard was running across the hot balck tarmac as the temperature was close to 50 degrees Celsius as it was almost midday. It stopped briefly in the middle of the raod and then ran off into the desert, but allowed me time to take one photograph of it.. I have seen many Arabian Spiny-tailed Lizards but have never seen one this bright yellow. They change colour as they warm up going from a dull ble grey to a bright yellow, like this one. The Arabian Spiny-tailed Lizard occurs in deserts and semi-deserts of Arabia and their spiked tail is muscular and heavy, and when threatened can be swung at an attacker with great velocity, usually accompanied by inflation of its body and hissing loudly, caused by expelling air, and an open-mouthed display of (small) teeth. It is one of the largest members of the genus, with maximum total lengths of greater than 700 mm for males and a weight of approximately 1.6 kilograms. It has a predilection for open habitats with hard substrates into which it can dig, such as gravelly plains and firm sandy areas containing coarse sand, gravel and sparse vegetation. Mountainous areas and habitat with thick layers of stones and rocks are not suitable. In Saudi Arabia the distribution extends horizontally in the middle of the Kingdom from the Red Sea coastal desert in the west to the Arabian Gulf in the east. It is fairly common in the eastern scrub desert of Saudi Arabia, especially in its northern reaches, up to and including the Dibdibah alluvial plains near Hafr al-Batin. Population density in central Saudi Arabia is between 0.1 and 4 specimens per hectare (Kordges 1998).