Abstract
Millipedes are widely distributed in Saudi Arabia but they were not studied before. In Taif governorate, two species were found that are similar morphologically, which resulted in incorrect identification of these species. Therefore, this work aimed to combine morphological identification with genetic analysis. Specimens were separated morphologically into two species Archispirostreptus syriacus and A. tumuliporus. The first species was recorded in Arruddaf, Maysaan, Thaqif, Bani Saad and Maysaan, the second occurs in Alshafa and Maysaan. The phylogenetic tree inferred from cytochrome c oxidase I (COI) sequences separated samples that were identified as A. tumuliporus from those identified as A. syriacus. Also, a dendrogram based on ISSR-PCR showed these two species in separate clusters.