External anatomy and muscle morphology of the walking legs of the scorpion Hadrurus arizonensis

Abstract

1. 1. The relationships between total leg length, leg segment length and body size for different sized scorpions ( Hadrurus arizonensis) are described. Ipsilateral walking legs are differentially oriented (Fig. 1). Leg length increases in progressively more posterior legs (Fig. 2). 2. 2. Unlike the situation in insects and crustaceans, in the scorpion the joint between the body and the coxa is relatively immobile. The coxa-trochanter (C-T) joint is monocondylic, permitting relatively complex movements, while the remaining leg joints are dicondylic, planar joints (Fig. 5). 3. 3. The C-T joint musculature is relatively complicated reflecting the complexity of joint movement (Fig. 3). The more distal joints are controlled by simpler antagonistic muscle arrangements (Fig. 4).