QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 2, 2008
Journal of Experimental Biology 211, 1612-1622 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.013029

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Google Scholar Articles by Horner, A. M. Articles by Jayne, B. C. PubMed PubMed Citation Articles by Horner, A. M. Articles by Jayne, B. C.

The effects of viscosity on the axial motor pattern and kinematics of the African lungfish (Protopterus annectens) during lateral undulatory swimming

Angela M. Horner^* and Bruce C. Jayne

Department of Biological Sciences, University of Cincinnati, PO Box 210006, Cincinnati, OH 45221-0006, USA

^* Author for correspondence at present address: Department of Biological Sciences, Ohio University, Irvine Hall, Athens, OH 45701, USA (e-mail: ah312505{at}ohio.edu)

Accepted 7 March 2008

Separate studies of terrestrial and aquatic locomotion are abundant, but research addressing locomotion in transitional environments (e.g. mud) is scant. The African lungfish (Protopterus annectens) moves in a gradation of water to mud conditions during seasonal droughts, and breathes air. Thus, the lungfish was an ideal organism for our study to determine the effects of a wide range of viscosities on lateral undulatory swimming and to simulate some of the muddy conditions early tetrapods may have encountered. Regardless of viscosity, several aspects of lungfish swimming were similar to those of other swimming vertebrates including: posteriorly propagated muscle activity that was unilateral and alternated between the left and right sides at each longitudinal location, and posterior increases in the amount of bending, the amplitude of muscle activity and the timing differences between muscle activity and bending. With increased viscosity (1–1000 cSt), significant increases occurred in the amount of lateral bending of the vertebral column and the amplitude of muscle activity, particularly in the most anterior sites, but the distance the fish traveled per tail beat decreased. The magnitude of the phase shift between EMG onset relative to bending increased by as much as 13% of a cycle with increased viscosity, so that the muscles were increasingly active during lengthening rather than shortening. Therefore, with increased viscosity the relationship between axial muscle activity and bending in the lungfish became more dissimilar rather than converging on the motor pattern used by other ectothermic vertebrates when undulating in fully terrestrial environments.

Key words: locomotion, lungfish, EMG, kinematics, swimming, viscosity, tetrapod evolution

Related articles in JEB:

HOW AFRICAN LUNGFISH SWIM THROUGH MUD

Kathryn Phillips
JEB 2008 211: 0. [Full Text]  

This article has been cited by other articles:

				K. Phillips HOW AFRICAN LUNGFISH SWIM THROUGH MUD J. Exp. Biol., May 15, 2008; 211(10): i - ii. [Full Text] [PDF]