†This paper is based on embryos and larvae of Neoceralodus raised from eggs collected in the field by the late Dr H. P. Whiting during two visits to Australia in 1976 and 1978/9. Dr Whiting fixed a range of stages and, in collaboration with Dr Barwick, made kinematographic records at the Australian National University of the responses to mechanical stimuli at different stages of development. He analysed these records (wherever possible we have re-drawn response sequences from his original drawings), but he was unable to make other than a preliminary examination of the histology of the nervous system in the specimens he had fixed. Dr Whiting did not leave a draft outline of his intended paper, but he discussed it with QB and LHB, and this account combines his observations with our own later histological work on his specimens.
Early locomotor behaviour and the structure of the nervous system in embryos and larvae of the Australian lungfish, Neoceratodusforsteri‡
Article first published online: 23 MAR 2009
Journal of Zoology
Volume 226, Issue 2, pages 175–198, February 1992
How to Cite
Whiting, T. L. H. P., Bannister, L. H., Barwick, R. E. and Bone, Q. (1992), Early locomotor behaviour and the structure of the nervous system in embryos and larvae of the Australian lungfish, Neoceratodusforsteri‡. Journal of Zoology, 226: 175–198. doi: 10.1111/j.1469-7998.1992.tb03833.x
- Issue published online: 23 MAR 2009
- Article first published online: 23 MAR 2009
- Accepted 4 December 1990
This paper describes the development of early locomotor responses to mechanical stimulation in the Australian lungfish Neoceralodus and compares them with structural changes in the spinal cord. Initial movements occur spontaneously prior to innervation of myotomal muscles, and are therefore myogenic. After muscle innervation, embryos only move when stimulated; the first type of response to sharp touch is a unilateral flexion away from the stimulus, then at a later stage the contralateral response is followed by a homolateral flexure which, later still, passes into bursts of swimming. The initial contralateral response occurs when decussating interneurons are detectable but before spinal sensory innervation of the trunk; however, the trigeminal sensory pathway has been established by this time and probably mediates the first mechanoreceptive signals from trunk epidermis. Later, Rohon-Beard cells innervate the trunk skin, and then dorsal root neurons take over the major sensory role. The secondary homolateral response and bursts of swimming are paralleled by the development of several types of spinal interneurons and the ingrowth of Mauthner cell axons.