Herpetology Notes, volume 11: 239-242 (2018) (published online on 11 April 2018)

Notes on the Natural History of Trachydactylus spatalurus (Anderson, 1901) in southwestern Oman

Frank Colacicco1,*, Michael-Bernd Zwanzig2, Wolfgang Grossmann3 and Thomas Kowalski4

Trachydactylus spatalurus (Anderson, 1901) is were conducted between ca. 2000–0100 h in habitat regarded as an enigmatic and rare species in Arabian considered suitable based on geographic location herpetology (Gardner, 2013; Fig. 1). Recent taxonomic (S. Carranza, pers. comm.), available microhabitat, changes within the genus Bunopus Blanford, 1874 and accessibility in a vehicle. Our search techniques resulted in the resurrection of Trachydactylus (de Pous et involved searching for geckos after dark with handheld al., 2015), but only very little is known about the natural flashlights, often walking distances up to 1 km history, conservation status, phylogenetic relationships, (measured using road markers) from the vehicle during and preferred habitats of these interesting geckos. This a survey. All discovered specimens were measured, lack of information is primarily due to research teams visually sexed, photographed, and released. having found so few individuals in confirmed localities Locality 1.—The first locality sampled was near that are widely scattered, from southwestern Oman to Thumriat, in the Dhofar Region. In the evening, we central Yemen. Fewer than five specimens have been drove roughly 25 km south from Thumriat on Highway collected and catalogued (S. Carranza, pers. comm.) 31 and headed into the desert by driving up a dry wadi. since the species was first discovered in Yemen during About 10 km into the wadi (ca. 17.4204°N, 54.0556°E) an expedition by A. Blayney Percival in 1900. In we began to search for geckos, at ca. 2200 h. The habitat contrast, the sister species T. hajarensis (Arnold, 1980) was a heavy gravel wash with sloped sides and some is quite common throughout its range and easily found small trees spread throughout (Fig. 3A). There were (pers. obs.). With coastal areas of southern Oman now intermittent patches of sand, and some small cave like becoming more and more developed, it is important structures along the slopes. The air temperature was to compile a more comprehensive data set of the warm (28.3°C) and the relative humidity was ≤ 50%. distribution and true relative abundance of these geckos. We immediately began to find Stenodactylus In this paper we explore the hypothesis that T. spatalurus is restricted to, but locally abundant in, small pockets of suitable habitat within an overall larger range. During fieldwork on five separate occasions (11–13 August 2014, 11–20 May 2015, 19–22 October 2015, 16–24 February 2016, 20–30 March 2017), we travelled to three locations in southern Oman (Fig. 2) in hopes of locating individuals of T. spatalurus. Surveys

1 13273 Fiji Way, Suite 318, Los Angeles, California 90292, USA 2 Kurze Straße 5, 15859 Storkow, Germany 3 Wulfila-Ufer 33, 12105 Berlin, Germany Figure 1. Gravid adult female Trachydactylus spatalurus 4 Holzweg 63, 25337 Elmshorn, Germany (SVL ca. 50 mm) from a wadi near Thumriat, Oman. Photo * Corresponding Author E-mail: [email protected] by����������������� Frank Colacicco. 240 Frank Colacicco et al.

February 2016 and located two males and one female T. spatalurus. Locality 2.—Traveling southwest of Salalah, we surveyed the area of Mughsail. At ca. 16.8895°N, 53.7797°E is a large wadi that includes a marsh with a year-round water supply that supports a great diversity of wildlife. The wadi is roughly 100 m wide with a steep cliff on one side and a gentle but boulder-strewn slope on the other (Fig. 3B). The wadi floor is soil near the marsh, and soil/gravel towards the sloping side. The ground is loosely covered in rocks ranging in size from 3–60 cm in diameter. This wadi supports no Stenodactylus and very few P. carteri (pers. obs.). Other geckos found in

Figure 2. Map of the southeastern Arabian Peninsula and surrounding areas. The inset shows localities in southwestern Oman where individuals of Trachydactylus spatalurus were found. Numbered circles in the inset represent the three locations sampled during our studies, identified as 1 = ca. 17.4204°N, 54.0556°E; 2 = ca. 16.8895°N, 53.7797°E; and 3 = ca. 17.0382°N, 54.2770°E.

leptocosymbotes Leviton and Anderson, 1976 and Pristurus carteri (Gray, 1863). These geckos were very common on the desert floor but were absent from the sloping sides. As we moved out of the wider part of the wadi and into a narrower section, S. leptocosymbotes and P. carteri were replaced in the habitat by smaller geckos of the species Tropiocolotes scortecci Cherchi and Spano, 1963 and Hemidactylus minutus Vasconcelos and Carranza, 2014 on the slopes of the wadi walls. At approximately 2330 h we found a single female Trachydactylus spatalurus (Fig. 1) 10 m up the gentle sloping side of a small hill in the wadi. Within 2 m of the female we located a male. Both individuals were well above the wadi floor where the numerous S. leptocosymbotes and P. carteri dwell. The female had a snout–vent length (SVL) of 50 mm and the male had an SVL of 44 mm. Both animals appeared to be in good health with original tails. The female was gravid and two large eggs were visible through the ventral skin. Both animals were Figure 3. Habitats of Trachydactylus spatalurus in southwestern measured, photographed, and released. The microhabitat Oman. (A) South of Thumriat (Locality 1).������������������ Geckos were found was a slightly sloping hillside covered in coarse gravel on the low slopes of the hillsides. (B)�������������������������� Mughsail (Locality 2). and larger rocks. No vegetation was present on the The microhabitat where geckos were located is the scattered hillsides, but small bushes could be found in the bottom stones in the foreground of the photograph. (C) Salalah plain of the wadi. The only other geckos immediately present (Locality 3). During the height of the monsoon season in July, in this microhabitat were T. scortecci and H. minutus. these plains can become green with grass. Photos by Wolfgang We returned to the same wadi on a subsequent trip in Grossmann (A, C) and Frank Colacicco (B). Notes on the Natural History of Trachydactylus spatalurus in Oman 241 this wadi are Ptyodactylus dhofarensis Nazarov et al., the site, eight individuals (five males, three females) 2013, Hemidactylus minutus Vasconcelos and Carranza, was the minimum number located in just over 45 min, 2014, Hemidactylus festivus Carranza and Arnold, 2012, and as many as 16 individuals (ten males, six females) and Pristurus sp. 1 (a population formerly reported as P. were seen in a 90-min survey. 80% of the animals found rupestris and labelled as a new species by Badiane et al., were adults. At this site, T. spatalurus can be considered 2014). Diurnal lizards included Trachylepis brevicollis common, and it is the second most frequently seen (Wiegmann, 1837) and Pseudotrapelus cf. sinaita species (Fig. 4) by our team (second to Pristurus carteri). (Heyden, 1827). The snake fauna included Telescopus d. We observed large colonies of subterranean termites dhara Gasperetti, 1988, Psammophis schokari (Forskal, active after dark throughout the search site, and also 1775), and the Burrowing Asp, Atractaspis andersonii witnessed T. spatalurus actively hunting them. Pristurus Boulenger, 1905. The vipers Echis khosatzkii Cherlin, carteri, Pristurus sp. 1, Hemidactylus robustus Heyden, 1990 and Bitis arietans (Merrem, 1820) are occasionally 1827, and H. paucituberculatus Carranza and Arnold, seen here, and the toad Duttaphrynus dhufarensis 2012 are the other geckos found in this area. Echis (Parker, 1931) is common. khosatzkii, Telescopus d. dhara, Atractaspis andersonii, We searched this wadi at night, from just after dark (ca. and Spalerosophis diadema cliffordii (Schlegel, 1837) 2100 h) until 0100 h on 11 May 2015 and 16 February can also be found here. 2016. On the first date we found one male, three females, and one juvenile T. spatalurus on the floor of the wadi. The month of May appears to be part of the breeding season for T. spatalurus, as two of the three females were gravid. Temperatures ranged from 25–32ºC and the humidity averaged 80%. On 16 February 2016 we returned to the same site and used the same active search techniques. Three male and four female T. spatalurus were located this time, in the same environmental situations as stated earlier. However, this time no females appeared to be gravid. The geckos were always found directly on the ground, never perched on a rock or clinging to vertical surfaces. It was difficult to spot these animals due to the closeness of the rocks to each other. The geckos appear to be able to run undetected through these “corridors.” When approached, some individuals would cease all movement and crouch to the ground. Others would stand very high on straight legs and lunge with mouth open. These geckos, when frightened, are able to produce a high-pitched one syllable “scream” as Figure 4. Four Trachydactylus ����������spatalurus from the Salalah well (pers. obs.). plain (Locality 3), including two males (top two geckos), one female, and one juvenile (bottom). Photo by Frank Colacicco. Locality 3.—East of Salalah, along Highway 49 (ca. 17.0382°N, 54.2770°E), is a barren plain that appears almost entirely void of life. The terrain is nearly flat with scattered small (<10 cm in diameter) stones on a Discussion sandy soil (Fig. 3C). Plant life is minimal, with very few small shrubs and grasses being the only vegetation Trachydactylus spatalurus was found to be relatively present. This area was surveyed in the spring (20–22 common once the correct microhabitat was located. March 2017, 11–14 May 2015), summer (11–13 August Questions as to what exactly is the preferred microhabitat 2014), and fall (19–22 October 2015). Temperatures still remain, due to the differences found between Site averaged 27ºC with 80% humidity. Typically we began 1 and Sites 2 and 3. Humidity and elevation are quite searches at this location after darkness, and from the different at these sites, while their general terrain is vehicle parked on the road we would walk up to 0.5 km similar. This paper should be taken as a work in progress due north during the survey. During the three visits to as future studies will focus on locating animals in areas 242 Frank Colacicco et al. between these three sites, and also gaining a general understanding of what constitutes the preferred habitat for these interesting geckos.

Acknowledgments. We collectively thank Paul Woehl, David Mouton, and Hans-Jürgen Zilger for their help in the field, Salvador Carranza and Hinrich Kaiser for their editing help, general correspondence, and advice in writing this paper, and each of our spouses for their patience with our time-consuming interests.

References

Arnold, E.N. (1980): The scientific results of the Oman flora and fauna survey 1977 (Dhofar). The reptiles and amphibians of Dhofar, southern Arabia. Journal of Oman Studies Special Report (2): 273–332. Badiane, A., Garcia-Porta, J., et al. (2014): Phylogenetic relationships of Semaphore geckos (Squamata: Sphaerodactylidae: Pristurus) with an assessment of the taxonomy of Pristurus rupestris. Zootaxa 3835: 33–58 Carranza, S., Arnold, E.N. (2012): A review of the geckos of the genus Hemidactylus (Squamata: Gekkonidae) from Oman based on morphology, mitochondrial and nuclear data, with descriptions of eight new species. Zootaxa 3378: 1–95. de Pous, P., Machado, L., Metallinou, M., Červenka, J., Kratochvíl, L., Paschou, N., Mazuch, T., Šmíd, J., Simó-Riudalbas, M., Sanuy, D., Carranza, S. (2015): Taxonomy and biogeography of Bunopus spatalurus (Reptilia; Gekkonidae) from the Arabian Peninsula. Journal of Zoological Systematics and Evolutionary Research 54: 67–81. Gardner, A.S., (2013). The Amphibians and Reptiles of Oman and the U.A.E. Frankfurt am Main, Germany, Edition Chimaira. 480 pp.

Accepted by Hinrich Kaiser