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Title: Studies on intertidal lepadomorpha and balanomorpha
Author: Hui, E.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1983
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Field and laboratory observations and experiments on lepadomorph and balunomorph barnacles have provided information on the ecology and phylogeny of intertidal thoracican Cirripodia. The lopadomorphs Capitulum mitella in Hong Kong, and Follicipos pollicipos in France were ecologically similar, but differences in morphology and vertical distribution between species seemed attributable to adaptation to local predation pressures. Experiments on Chthamalus montagui, Elminius modestus and Semibalanus balanoides in South Wales vindicated a recently questioned study, confirming that S. balanoides cyprids avoid contact settlement with adult conspecifics. Such behaviour was not found in the other two species. Further experiments independently suggested that specific avoidance is adaptive in reducing spat mortality, rather than in direct interspecific competition. Studies on competition between these three balanomorphs suggested that the mid-littoral abundance of E. modestus despite heavy crowding mortality from S. balanoides seemed attributable to the short generation time, fast growth and prolonged settlement of E. modestus; allowing this immigrant to utilize available rock surface to the exclusion of S. balanoides which has a short settlement season. Early maturation also allows E. modestus to utilize short-lived substrata such as the parietes of established barnacles, a previously unfilled local niche. The Balanomorpha are accepted to be descended from the Lepadomorpha. Observations made during this study suggested an examination of the primitive balanomorph Chionelasmus darwini. This clarified the relationship between the two suborders, showing that Chionelasmus could not be descended from Catomerus, and that neither evolved from the lepadomorph Scillaelepas. The Bathylasma-like complemental male of Chionelasmus was discovered and described, supporting its recent classification in the Fachylasmidae. These results indicated that the Balanomorpha evolved polyphyletically in shallow sea or intertidal environments via both Chionelasmus and Catomerus from Capitulum-like and Pollicipes s.s.-like lepadomorph ancestors respectively.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available