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Stereoscopic vision in one eye: paleophysiology of the schizochroal eye of trilobites

Published online by Cambridge University Press:  08 April 2016

William L. Stockton
Affiliation:
Department of Geology, and Graduate Group in Ecology, University of California; Davis, California 95616
Richard Cowen
Affiliation:
Department of Geology, University of California; Davis, California 95616

Abstract

The schizochroal eye of trilobites bears lenses of high optical quality. Cooperation between adjacent lenses, which must have had retinas rather than rhabdomeres, might have allowed the trilobite stereoscopic vision throughout its visual field. We propose a simple neurophysiological model for the schizochroal eye in which neural connections between lenses on vertical “visual strips” could have provided the integration necessary for stereoscopic vision. Simple neural signals could have coded information on the position, size, speed and nature of an object in the field of view. The model of stereoscopic vision is consistent with data on the shape of the eye, the arrangement of lenses on its surface, and with current views on the origin and early evolution of the schizochroal eye. It implies that the lens arrangement, neural network and shape of the eye surface were a coadapted morphological complex, and it is consistent with accepted ideas of the Phacopina as living in benthic habitats in the photic zone.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

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