This study documents the first confirmed record of the Buthid scorpion Leiurus nigellus from Jabal Arnan in the Ha’il region, located within the King Salman Bin Abdulaziz Royal Natural Reserve (KSRNR) in the northwestern Kingdom of Saudi Arabia (KSA). This species was originally described by Abu Afifeh, Aloufi & Al-Saraireh (2023). This locality extends the known distribution range of L. nigellus by over 200 km southeast of the type locality in Al-Ula, Al Madinah province. A total of six specimens of L. nigellus were collected during fieldwork conducted between June 2024 and April 2025, including two adult males, one adult female, and three juveniles. The objective of this study was to confirm the taxonomic identity of Leiurus nigellus from a newly discovered locality using morphological examination and mitochondrial DNA analysis and documentation of its known geographic distribution. Adult specimens (one male and one female) were examined using comparative morphometric analysis following standard scorpion taxonomic protocols, confirming diagnostic traits consistent with the original species description. Meanwhile, habitat assessments indicated adaptation to semi-arid rocky and gravel substrates. Molecular analysis was conducted on one adult male using targeted mitochondrial 16S rRNA gene sequencing (Sanger method). Phylogenetic relationships were inferred using neighbor-joining and maximum-parsimony analyses, placing L. nigellus within the Arabian Leiurus clade with bootstrap-supported affinity to Arabian congeners and limited intraspecific divergence. The generated 16S rRNA sequence represents the first molecular record for L. nigellus and has been deposited in GenBank. Sexual dimorphism was evident in morphometric traits, but these differences reflect normal biological variation rather than taxonomic differentiation. The discovery of L. nigellus in northern Saudi Arabia emphasizes the importance of continued faunistic and genetic surveys in underexplored regions, both to refine species distributions and to inform conservation management of specialized desert arachnofauna.
Al-Amri et al. (Sat,) studied this question.