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The neotenous origin of the pollen organ of the gymnosperm Cycadeoidea and implications for the origin of higher taxa

Published online by Cambridge University Press:  20 May 2016

Benton M. Stidd
Benton M. Stidd*
Affiliation:
Department of Biological Sciences, Western Illinois University, Macomb, IL 61455
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Abstract

Previous descriptions and interpretations of the Cycadeoidea pollen organ are followed by a new interpretation based upon its presumed neotenous condition. The sexually mature pollen organ represents a juvenile morphological condition that persisted into the adult stage of the organism and was inherited ultimately from a seed fern ancestor. The neotenous organ is considered to have come into existence abruptly and the altered morphology to have been achieved without an intervening series of intermediates. Abrupt establishment of higher taxa by heterochrony constitutes a mechanism capable of decoupling microevolutionary processes from macrevolutionary differences and poses a distinct challenge to current evolutionary theory.

Type
Articles
Information
Paleobiology , Volume 6 , Issue 2 , Spring 1980 , pp. 161 - 167
Copyright
Copyright © The Paleontological Society 

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