Biology, morphology and molecular study of Sassanidotus gracilis (Birula, 1900) (Arachnida: Scorpiones)

Abstract Sassanidotus (Scorpiones: Buthidae) is a small genus of scorpions described by Farzanpay (1987). The size of adult members is about 50 mm and overall color of the body is yellow. This genus has two species. Sassanidotus gracilis (Birula, 1900) has been described morphologically from Zabol, southeast of Iran. Sassanidotus zarudnyi (Birula, 1900) was described based on a holotype from Teheran, North of Iran. Limitations in morphology-based identification systems indicate the need for molecular study to taxon identification. To confirm the validity and redescription of Sassanidotus gracilis, twenty specimens collected from Sistan & Baluchistan province were studied morphologically and molecularly. Sassanidotus gracilis were redescribed. Maximum likelihood and Bayesian inference phylogenetic trees show that members of Sassanidotus were placed at the top of trees as the sister group of the Mesobuthus. Both genera are very similar morphologically. The genetic difference between different genera confirms Sassanidotus validity. Five pairs of living specimens were studied to investigate the biology of the species. Litter size for S. gracilis was 15–19.