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Zoology in the Middle East Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tzme20 Notes on a sympatric population of two of spiny-tailed in : dispar Heyden, 1827, and U. ocellata Lichtenstein, 1823 (Sauria: ) Elagba H. A. Mohammed a & Dawi M. Hammad b a Natural History Museum, Faculty of Science, University of Khartoum, P. O. Box 321, Khartoum, Sudan b Zoology Department, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum, Sudan Version of record first published: 28 Feb 2013.

To cite this article: Elagba H. A. Mohammed & Dawi M. Hammad (2008): Notes on a sympatric population of two species of spiny-tailed lizards in Sudan: Heyden, 1827, and U. ocellata Lichtenstein, 1823 (Sauria: Agamidae), Zoology in the Middle East, 44:1, 51-56 To link to this article: http://dx.doi.org/10.1080/09397140.2008.10638288

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by Elagba H. A. Mohammed and Dawi M. Hammad

Abstract: A series of 27 Uromastyx was collected at Abu Hammad, Nile State, northern Sudan, consisting of two distinct, sympatric species: three U. dispar Heyden, 1827 and 24 U. ocellata Lichtenstein, 1823. The morphological analysis of these specimens reveals some data exceeding the previously known range of variability in these two species, including the maximum length.

Key words. Uromastyx dispar, , morphology, cluster analysis, Sudan.

Introduction Two species of Uromastyx are known from Sudan: Uromastyx dispar Heyden, 1827, and U. ocellata Lichtenstein, 1823. In the most recent revision of the (WILMS 1998, WILMS & BÖHME 2000, 2001), the latter species is treated as monotypic, because these authors con- sider both U. ornata Heyden, 1827 and U. macfadyeni Parker, 1932, known from southeast- ern , Sudan, Eritrea, Djibouti and northwesternmost , to represent distinct species. In contrast, U. dispar, originally described as U. acanthinurus dispar, is considered to represent a polytypic species occurring in the southern Saharan range, with three subspe- cies: U. d. dispar from Sudan and Tchad, U. dispar maliensis from southern and , and U. dispar flavifasciata from the , westernmost Algeria, and Mauri- tania. The nomenclatural histories of both species, reflecting earlier, differing taxonomic concepts, can be found in the synonymy/chresonymy lists given in WILMS & BÖHME (2001). Whereas U. ocellata is widespread and regionally abundant, and is well represented in interna- tional natural history museums including samples from Sudan, the nominotypic form of U. dispar Downloaded by [197.208.167.192] at 13:42 10 March 2013 is much rarer in collections. Most specimens originate from Tchad; from Sudan, only three specimens, including the lectotype, were previously known, originating from Wadi Halfa, south- east of El Debba and Ambukol respectively (see WILMS & BÖHME 2001). The three specimens from Abu Hammad described in this paper double the number of Sudanese voucher specimens of this taxon.

Material and methods Twenty-seven specimens of Uromastyx were taken from the living collection of the Sudan Natu- ral History Museum. All specimens were previously obtained from Abu Hammad in the Nile State in the north of the Sudan. Eighteen characters were measured for each specimen: total length (TL), standard length (SL), head length (HL), snout length (SNL), snout-vent length (SNVL), tail length (TaL), eye-ear length (EEL), head width (HW), mouth width (MW),

Zoology in the Middle East 44, 2008: 51–56. ISSN 0939-7140 © Kasparek Verlag, Heidelberg 52 Zoology in the Middle East 44, 2008

Table 1. Descriptive statistics of nineteen morphological characters for 3 specimens of Uromastyx dispar and 24 specimens of U. ocellata from northern Sudan.

Character N Mean Maximum Minimum 3 380.7 399.0 362.3 Total length (TL) 24 244.7 321.9 202.5 3 224.3 244.4 204.2 Standard length (SL) 24 133.3 152.4 114.2 3 44.7 50.8 38.6 Head length (HL) 24 27.4 31.3 23.4 3 12.7 19.0 6. 4 Snout length (SNL) 24 10.5 14.6 6.3 3 241.3 250 233 Snout-vent length (SNVL) 24 146 176 104 3 183 185 180 Tail length (TaL) 24 156.3 180 144 3 19.7 22.9 16.5 Eye-to-ear length (EEL) 24 12.8 15.2 9.8 3 45 47 43 Head width (HW) 24 28.5 33.4 21.0 3 36 40 29 Mouth width (MW) 24 21.9 26.3 17.6 3 8.7 10.2 7.2 Eye diameter (ED) 24 6.1 8.0 4.2 3 24.3 25.9 22.8 Inter-orbital distance (IOD) 24 16.3 19.5 13 3 9 10 8 Inter-nasal distance (IND) 24 6.6 8.0 5.3 3 40.3 44.8 35.8 Inter-audial distance (IAD) 24 23.8 27.7 19.9 3 89.7 94.2 85.2 Body depth (BD) 24 49.8 63.1 36.5 3 27.7 30.9 24.5 Peduncle width (PW) 24 18.5 23.1 13.9 3 35.3 37.9 32.8 Tail width (TaiW) 24 22 26.8 15.0 3 25 30 20 Pores number (PNO) 24 28 40 25 3 20 23 18 Downloaded by [197.208.167.192] at 13:42 10 March 2013 Whorls numbers (WNO) 24 24 29 17 3 396.9 450.0 346.6 Body weight (BW) 24 145.6 235.0 185.5

eye diameter (ED), inter-orbital distance (IOD), inter-nasal distance (IND), inter-audial distance (IAD), body depth (BD), peduncle width (PW), and tail width (TaW). The number of pre-anal and femoral pores (PNO) and the number of whorls on the tail (WNO) were also recorded. Sex was determined after dissection. Total and standard length were measured by a ruler-board. A fine dial caliper was used to measure the other parameters. All measurements were taken to the nearest millimetre. Cluster analysis was used to investigate the homogeneity of the examined specimens and to see whether they belong to one single species, subspecies or races of a single species, according to

Reptilia 53

Fig. 1. Dendrogram based on morphological differences using average linkage (within and between groups) method, for 27 specimens of Uromastyx.

CLIFFORD & STEPHENSON (1975). Cluster based on matrix of distances for 19 morphological Downloaded by [197.208.167.192] at 13:42 10 March 2013 characters (including body weight) and complete linkage within and between groups was used to produce hierarchical clusters of the specimens in a distance dendrogram. The statistical package (SPSS/ PC 2000, version 10) was used for the evaluation of the data.

Results and discussion Cluster analysis separated the specimens studied into two separate groups (Fig. 1): one group comprised three specimens, and the other 24 specimens. The latter was further divided into two sub-clusters: one included four, that separated further into one and three specimens; the other sub-cluster divided further into two divisions, one including (1 + 6) and the other (3 + 9) specimens. The three specimens in the first dichotomy have a light beige skin without dots or stripes on the back, compared to the individuals of the other dichotomy. 54 Zoology in the Middle East 44, 2008

Fig. 2. Uromastyx dispar dispar.

The test for equality of means for the 19 characters (Table 1) of the two major groups (3 + 24) showed a significant difference (p<0.05) in 16 characters. The sub-clusters (19 + 5) differed in 14 characters, and the specimens in the subdivision (12 + 7) differed in nine char- acters. The specimens in the subdivision (9 + 3) differed in 9 out of the 19 characters. The colour pattern plus the small light dots throughout the back of the lizards separates two distinct taxa, probably species, of the genus Uromastyx. The presence of two rows of scales between every two whorls on the lower side of the tail of the three specimens in the first group is another diagnostic feature (Fig. 3). The analysis of 19 morphological characters has revealed a pattern of shape variation be- tween the examined specimens. Cluster analysis suggested the presence of two distinct spe-

Downloaded by [197.208.167.192] at 13:42 10 March 2013 cies that share some characters. The high diversity observed within the study population suggests the possibility of subspecies. But since all specimens were collected from the same area, it could be that some interaction took place between the genotype of the specimens with their local environment to produce different morphs of the . According to VERNET et al. (1988), morphological characters are environmentally more labile and thus change rapidly. However, the present data do not indicate the possibility of subspecies. Further taxonomic study on a biochemical and molecular basis could clarify the status of Uromastyx and support the present work. A good correspondence between biochemical- and morpho- logical-based taxonomic classifications is expected (GRISMER 1988). The presence of two species of Uromastyx is suggested from the present work and a descriptive diagnostic guide for their identification is provided below. This study shows that two species of Uromastyx inhabit the northern region of the Sudan: U. dispar dispar and U. ocellata. Other species are expected to be found in other parts of the country. Reptilia 55

Downloaded by [197.208.167.192] at 13:42 10 March 2013 Fig. 3a, b. Tail of U. dispar dispar showing that each whorl on the upper surface (a) corresponds with two rows of scales on the lower surface (b) of the tail.

Uromastyx dispar dispar Heyden, 1827 (Fig. 2) Identification. One of the largest and most impressive lizards, with a relatively long tail usually 77% of SVL (length 5-6 times width), tapering towards its tip, flattened with 20 (18- 23) large strongly-keeled whorls and enlarged scales on the flanks and very small or minute dorsal scales. One whorl on the upper side of the tail corresponds with two rows of scales on its lower surface (Fig. 3a, b). The additional scales may be arranged in symmetrical or asym- metrical rows; pre-anal and femoral pores present. Measurements. Mean and range of: Total length 380.7 (362.3–399.0) mm; tail length 183 (180–185) mm; SVL 241.3 (233–250) mm; body weight 396.9 (346.6–450.0) g. 56 Zoology in the Middle East 44, 2008

Colour. Light beige to orange, slightly dotted or reticulated. Remarks. The spinous scales on the flanks of U. dispar dispar have been used to distinguish this species, which is known from the Arabian Peninsula, Syria, Iraq and Sudan. The pres- ence of one whorl on the upper side of the tail that corresponds with two rows of scales on its lower surface is another potential diagnostic character.

Uromastyx ocellata Lichtenstein, 1823 Identification. A relatively short and narrow tail, usually 90% of SVL (length 4-4.5 times width) regularly tapering from base, with 24 (17-29) whorls and spines on both sides at the same level on the convex upper surface. Whorls on the upper side of the tail equal in number to transverse rows of scales on its lower surface. Pre-anal and femoral pores present. Measurements. Mean and range of: Total length 244.7 (202.5–321.9) mm; tail length 156.3 (144.3–180.0) mm; SVL 176 (146–210) mm; body weight 145.6 (185.5–235.0) g. Colour. Ground colour greyish or yellowish-brown, orange, brick-red or yellow with dots, small bars, pseudo-ocelli or several types in combination, with very variable dorsal patterns. Grey when leaving their burrows in the morning, and become coloured quickly, with the visible pigmentation increasing rapidly in the presence of bright light and heat. This is most noticeable when the is warming up during basking.

Acknowledgement. Our thanks and gratitude go to Professor Dr W. BÖHME for revising the manuscript.

References CLIFFORD, H. & T. STEPHENSON (1975): An introduction to numerical classification. – New York, San Francisco, London. GRISMER, L. L (1988): Phylogenetic Relationships of the Spiny Lizards Families. In: R. ESTES & G. PREGILL (Eds.), Stanford University Press p. 369- 469, Stanford (California). VERNET, R., M. LEMIRE, C. J. GRENOT & J. FRANCAZ (1988): Ecophysical comparisons between two large Saharan lizards, (Agamidae) and Varanus griseus (Varanidae). – Jour- nal of Arid Environments 14: 187–200. Downloaded by [197.208.167.192] at 13:42 10 March 2013 WILMS, T. (1998): Zur Taxonomie, Zoogeographie und Phylogenie der Gattung Uromastyx (Sauria: Agamidae sensu lato) mit Beschreibung zweier neuer Arten aus dem südöstlichen Arabien und aus der Zentralsahara. – MSc thesis, University of Kaiserslautern, 144 pp. WILMS, T. & W. BÖHME (2000): Zur Taxonomie und Verbreitung der Arten der Uromastyx ocellata- Gruppe (Sauria. Agamidae). – Zoology in the Middle East 21: 55–76. WILMS, T. & W. BÖHME (2001): Revision der Uromastyx acanthinura-Artengruppe, mit Beschreibung einer neuen Art aus der Zentralsahara. – Faunistische Abhandlungen aus dem Museum für Tierkun- de Dresden 51: 73–104.

Authors’ addresses: Mrs Elagba Haj Ali Mohammed, Natural History Museum, Faculty of Science, University of Khartoum, P. O. Box 321, Khartoum, Sudan. – Dawi Musa Hammad, Zoology Depart- ment, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum, Sudan. – Email contact: [email protected].