: Review of the taxonomy of the spiny-tailed lizards of Arabia (Reptilia: Agamidae: Leiolepidinae: Uromastyx)مراجعة تصنيفية للسحالي شوكية الذليل في شبه الجزيرة العربية (الزواحف: العظائيات:Leiolepidinae: Uromastyx)

Review of the taxonomy of the

spiny-tailed lizards of Arabia

(Reptilia: Agamidae: Leiolepidinae: Uromastyx)

Thomas M. Wilms and Wolfgang Böhme

Authors’ addresses:

Thomas M. Wilms, Reptilium – Terrarien- und WüstenZoo, Werner-Heisenberg-Str. 1, 76829 Landau, Germany; e‑mail: thomasmwilms@yahoo.de

Wolfgang Böhme, Zoologisches Forschungsmuseum A. Koenig, Adenauerallee 160, 53113 Bonn, Germany; e‑mail: W.Boehme.ZFMK@uni-bonn.de

Abstract: Currently six species of the genus Uromastyx (Reptilia: Agamidae: Leiolepidinae), representing three phylogenetic lineages, are known to occur in Arabia: Uromastyx aegyptia, U. benti, U. leptieni, U. ornata, U. thomasi and U. yemenensis. The present paper gives an overview of the taxonomy of these lizards and presents new data on the morphology and ecology of Uromastyx leptieni.

مراجعة تصنيفية للسحالي شوكية الذليل في شبه الجزيرة العربية

(الزواحف: العظائيات:Leiolepidinae: Uromastyx)

ثوماس ويلمز وولفا جانج بومه

INTRODUCTION

Spiny-tailed agamas are small to medium-sized, ground- or rock-dwelling lizards. Most species reach a maximum length of 25.50 cm, and only species of the Uromastyx aegyptia group can reach a total length of up to 70 cm or more. The animals have a bulky, depressed body and strong, short limbs. The tail is covered by spiny scales, arranged in distinct whorls. The tympanum is visible. None of the species has a nuchal or dorsal crest or a gular pouch or fan. Only a transverse fold at the throat is present (gular fold). Body scales are small and mostly homogenous, but some species have enlarged tubercular scales on the body and/or limbs.

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. This transformation of the premaxillary bone to a tooth-like structure is an autapomorphy of the genus Uromastyx, convergent in Sphenodon, which has also a convergently acrodont dentition. Owing to morphological, ethological and genetic synapomorphies, butterfly agamas of the genus Leiolepis are considered to be the closest living relatives of spiny-tailed lizards and both genera are therefore placed in the subfamily Leiolepidinae (synonym: Uromastycinae) (Peters 1971, Moody 1980, Böhme 1988, Schmitz et al. 2001, Amer & Kumazawa 2005).

Lizards of the genus Uromastyx occur in the desert belt of the Old World between 5°N and 35°N. Their range covers an enormous land mass, including northern Africa, the Middle East, Arabia, Iran, Iraq, Afghanistan, Pakistan and north-western India (Fig. 1). Today, 17 species are recognised, of which six species (with three additional subspecies) are native to Arabia (Kingdom of Saudi Arabia, Yemen, Sultanate of Oman, United Arab Emirates, Qatar and Kuwait (Wilms 2001, 2005; Wilms & Schmitz 2007).

The species of spiny-tailed lizards currently known to occur in Arabia are: Uromastyx aegyptia (Forskål, 1775), U. leptieni Wilms & Böhme, 2000, U. benti (Anderson, 1894), U. ornata von Heyden, 1827, U. yemenensis Wilms & Schmitz, 2007 and U. thomasi Parker, 1930. They represent three different phylogenetic groups, with species compositions listed below (Wilms 2001, Wilms & Schmitz 2007).

Uromastyx habitats are generally characterised by high temperatures, low precipitation, sparse vegetation and marked seasonal changes (Plates 1‑2). However, in the coastal regions of south and south-western Arabia (Asir and Hejaz Mountains, Hadramaut and Dhofar), Uromastyx habitats are more mesic because of the influence of the summer monsoon, resulting in high air moisture and elevated precipitation. These habitats are often well vegetated. Uromastyx species are mostly found on firm soil or on rock surfaces that provide shelter in the form of cracks and crevices. They also need, at least for part of the year, a sufficient amount of vegetation as a food source. Uromastyx live mainly in rocky desert and semi-desert habitats that are covered with rocks, scattered stones or gravel. Large continuous dune areas (erg) with drifting sand do not offer suitable habitats and represent range barriers. However, this does not prevent Uromastyx from travelling a few kilometres across sand from one gravel plain to another. Most species are digging, ground-dwelling animals, while some species live in rocky or mountainous areas and retreat into cracks and crevices. Some species have even been observed climbing acacia trees (U. aegyptia, U. dispar, U. ocellata and U. ornata). Uromastyx are opportunistic herbivores, which means, that they feed mainly on plants and to a lesser extent on animals. By far the largest part of the diet is leaves, flowers, sprouts and seeds of various plant species. Spiny-tailed agamas are strictly diurnal.