Journal of Comparative Physiology A

, Volume 180, Issue 2, pp 161–169

Coordination between the legs and tail during digging and swimming in sand crabs

  • Z. Faulkes
  • D. H. Paul

DOI: 10.1007/s003590050037

Cite this article as:
Faulkes, Z. & Paul, D. J Comp Physiol A (1997) 180: 161. doi:10.1007/s003590050037


Rhythmic leg movements and tailflipping are mutually exclusive behaviours in most decapod crustaceans, but sand crabs (Anomura: Hippoidea) combine leg movements with simultaneous tailflipping or uropod beating for both digging and swimming. We examined the coordination between the legs and tail (abdomen and tailfan) of Blepharipoda occidentalis, Lepidopa californica (Albuneidae), and Emerita analoga (Hippidae). When either albuneid swims, the tail cycles at a higher frequency than the legs, and the two rhythms are not coupled. When albuneids begin digging, the tail's frequency drops to that of the legs, and its rhythm becomes phase coupled to the legs. In E. analoga the legs seldom move during swimming by uropod beating. During digging the frequency of the uropods and fourth legs starts at about double that of the second and third legs, but drops to that of the second and third legs as digging progresses. The fourth legs in E. analoga are coupled with the uropods; their outward movement (= power stroke) is concurrent with the uropod return stroke. The familial differences in leg coordination and in the coordination of the legs and tail account for the smooth descent of E. analoga beneath sand compared to the stepwise descent of the albuneids.

Key words Tailflipping    Uropod beating Intersegmental coordination    Homology    Walking

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Z. Faulkes
    • 1
  • D. H. Paul
    • 1
  1. 1.Department of Biology, University of Victoria, PO Box 3020, Victoria, BC, Canada,␣V8W 3N5, Tel.: 1-250/721-8856, Fax: 1-250/721-7120, e-mail: dhp@uvvm.uvic.caCA