Vidal-Gadea A G, Rinehart M D, Belanger J H
Biological Sciences, LSB 248, Louisiana State University, Baton Rouge, LA 70803, USA.
Arthropod Struct Dev. 2008 Mar;37(2):95-108. doi: 10.1016/j.asd.2007.06.002. Epub 2007 Jul 5.
Crustaceans have been successfully employed to study legged locomotion for decades. Most studies have focused on either forwards-walking macrurans, or sideways-walking brachyurans. Libinia emarginata is a Majoid crab (Brachyura) and as such belongs to the earliest group to have evolved the crab form from homoloid ancestors. Unlike most brachyurans, Libinia walks forwards 80% of the time. We employed standard anatomical techniques and motion analysis to compare the skeleton, stance, and the range of motion of the legs of Libinia to the sideways-walking green shore crab (Carcinus maenas), and to the forwards-walking crayfish (Procambarus clarkii). We found animals tended to have greater ranges of motion for joints articulating in the preferred direction of locomotion. Leg segments proximal to such joints were comparatively longer. Thorax elongation, leg length and placement at rest also reflected walking preference. Comparative studies of walking in Libinia and other brachyurans may shed light on the neuroethology of legged locomotion, and on the anatomical and physiological changes necessary for sideways-walking in crustaceans.
几十年来，甲壳类动物一直被成功用于研究有腿动物的运动。大多数研究集中在向前行走的长尾类动物，或者侧向行走的短尾类动物上。缺刻Libinia蟹是一种蜘蛛蟹（短尾类），因此属于最早从同形类祖先进化出蟹形的群体。与大多数短尾类动物不同，Libinia蟹80%的时间是向前行走的。我们采用标准解剖技术和运动分析，将Libinia蟹的骨骼、姿势和腿部运动范围与侧向行走的绿岸蟹（Carcinus maenas）以及向前行走的小龙虾（Procambarus clarkii）进行比较。我们发现，动物在其偏好的运动方向上关节的运动范围往往更大。此类关节近端的腿部节段相对较长。胸部伸长、腿长和静止时的位置也反映了行走偏好。对Libinia蟹和其他短尾类动物行走的比较研究，可能有助于揭示有腿动物运动的神经行为学，以及甲壳类动物侧向行走所需的解剖学和生理学变化。
