Abstract

This study investigates the coxosternal or ventral sternal region, in scorpions and spiders. We collected 10 specimens of Scorpions from provinces Baghdad in region Abo Kreab and Salahuddin provinces in Tikrit then 7 specimens of Spiders were collected from variant regions in provinces Baghdad and various genera and families were collected and processed for examination. The aim was to compare the morphology of the coxosternal between these two arachnid groups and analyze the underlying functional and evolutionary implications of any structural variations. So the result of this study on coxosternal region of scorpions in the Family: Buthidae like Androctonus crassicauda, is not wide the majority of members of this family have a triangular cut and the female genital cover is divided, coxosternal region in Orthochirus scrobiculosus do not extend forward and do not form lobes, edges of the scales grainy and it is finely grained the majority of individuals have a triangular cut, Mesobuthus eupeus the ventral side is shiny and wide with strong hairs and the sternum is triangular, coxosternal region in Family: Scorpionidae like Scorpio Maurus in the ventral side do not have lobes extending forward, the sternum is pentagonal. But in Family: Salticidae of spiders the coxosternal region in Hasarius adansoni, are oval shape sternum or variable in Thyene imperialis, and Evarcha seyun, are circle shape sternum or variable, coxosternal region in Neoscona subfusca, family Araniedae are heart-shaped or triangular. The expected results include identifying distinct coxosternal shapes in scorpions compared to spiders. These variations might be linked to specific Roles like locomotion and internal organ protection. The determined geomorphology gets to render Understandings into the evolutionary relationships betwixt scorpions and spiders. This comparative analysis is expected to Add to a better understanding of how the coxosternal plays a role in the biology of scorpions and spiders. The known variations get bid important information along the development and practical adjustations inside these arachnids