Morphological characteristics of worm lizard, Diplometopon zarudnyi (Squamata: Trogonophidae), in the central region of Saudi Arabia

Abstract

We report morphometric data for 133 specimens of Diplometopon zarudnyi (Squamata: Trogonophidae) collected across its range within Riyadh province of Saudi Arabia. One-way analyses of variance revealed that differences exist in most characters. Snout-vent length and vent-tail length showed slight and inconsistent differences among samples. D. zarudnyi is characterized by 164–175 body annuli; 165–178 dorsal annuli; 13–17 caudal annuli with absence of caudal autotomy. In addition, 2–4 lateral annuli; 45–54 mid-body segments; 39–50 posterior segments; 4–5 head’s plates and 4–6 pre-cloacal pores were recorded in both males and females without gender difference. The present study revealed the widespread distribution of this species in the studied region, since land topography in this area is characterized by the absence of any natural barriers which could restrict the spread of this amphisbaenian lizard D. zarudnyi.

Intraspecific variation in the cranial osteology of Diplometopon zarudnyi (Squamata: Amphisbaenia: Trogonophidae)

“…The specimens of Diplometopon zarudnyi ranged from 153 to 198 mm for snout‐vent length and 168 to 215 mm for total length, which is consistent with the adult length measurements by Rudayni et al ( 2017 ) despite the desiccated state of the specimens in our sample. To control for the potential effect of desiccation on snout‐vent length and total length, maximum skull length and width were also measured and ranged from 7.27 to 8.76 mm and 4.33 to 5.46 mm, respectively.…”

“…However, the unreliability of inferring ontogeny from size at such low sample numbers hinders this finding. Additionally, the specimens in our study appear to be adults as indicated by their snout‐vent length and total length measurements matching the adult measurements reported by Rudayni et al ( 2017 ), so our sample is likely missing the earlier ontogenetic stages needed to confirm that interdigitation processes shorten with age.…”

“…Size can be used to infer ontogeny, although this method is unreliable with low sample numbers and produces results that are preliminary at best (Griffin et al, 2020 ). Additionally, without a way to infer ontogenetic stage, other factors such as sexual dimorphism could also be related to size (i.e., Rudayni et al, 2017 ). Nevertheless, a linear regression was performed using Minitab (version 19.2020.1, Minitab, LLC) for selected areas of variation versus snout‐vent length and maximum skull length to test for allometry, and thus a possible ontogenetic influence on variation.…”

“…It can be found in open areas with loose soil or sand, even those that are disturbed by human activity (Behbehani et al, 2012). One population of adults was found to vary from 135 to 221 mm in snout-vent length and 148 to 236 mm in total length (Rudayni et al, 2017) and were dietary specialists on Dermestes larvae (Al-Sadoon et al, 2016). Diplometopon zarudnyi and other members of Trogonophidae exhibit acrodont dentition, while all other extant amphisbaenians exhibit pleurodont dentition (Kearney, 2003).…”

Annotated Checklist of Reptilian Fauna of Basrah, South of Iraq

“…Niazi (1979) described Diplometopon shueaibi a new species from Karbala . Rudayni et al (2017) discoursed the variation within the Saudi Arabian Trogonophidae and they did not refer it to D. shueaibi Niazi, we believe that D. shueaibi is a valid name for central Arabia and west Karbala of Iraq.…”