part of pretarsus claw lever SPD:0000464 spider_anatomy The sclerotized median piece on the pretarsus, where the two tendons controlling the movement of the claws are connected (pretarsus levator and pretarsus depressor). It articulates with the tarsus by two basal lateral condyles (struts). The superior claws articulate with the claw lever by a movable joint. When present, the inferior claw arises from the pretarsus.